       1 /*
       2  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
       3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       4  *
       5  * This code is free software; you can redistribute it and/or modify it
       6  * under the terms of the GNU General Public License version 2 only, as
       7  * published by the Free Software Foundation.  Oracle designates this
       8  * particular file as subject to the "Classpath" exception as provided
       9  * by Oracle in the LICENSE file that accompanied this code.
      10  *
      11  * This code is distributed in the hope that it will be useful, but WITHOUT
      12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
      13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      14  * version 2 for more details (a copy is included in the LICENSE file that
      15  * accompanied this code).
      16  *
      17  * You should have received a copy of the GNU General Public License version
      18  * 2 along with this work; if not, write to the Free Software Foundation,
      19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
      20  *
      21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
      22  * or visit www.oracle.com if you need additional information or have any
      23  * questions.
      24  */
      25 package javax.swing;
      26
      27 import java.awt.*;
      28 import java.awt.event.*;
      29
      30 import java.util.Vector;
      31 import java.util.Locale;
      32 import java.util.ArrayList;
      33 import java.util.Collections;
      34 import java.util.List;
      35
      36 import java.beans.JavaBean;
      37 import java.beans.BeanProperty;
      38 import java.beans.PropertyChangeEvent;
      39 import java.beans.PropertyChangeListener;
      40 import java.beans.Transient;
      41
      42 import javax.swing.event.*;
      43 import javax.accessibility.*;
      44 import javax.swing.plaf.*;
      45 import javax.swing.text.Position;
      46
      47 import java.io.ObjectOutputStream;
      48 import java.io.IOException;
      49 import java.io.Serializable;
      50
      51 import sun.awt.AWTAccessor;
      52 import sun.awt.AWTAccessor.MouseEventAccessor;
      53 import sun.swing.SwingUtilities2;
      54 import sun.swing.SwingUtilities2.Section;
      55 import static sun.swing.SwingUtilities2.Section.*;
      56
      57 /**
      58  * A component that displays a list of objects and allows the user to select
      59  * one or more items. A separate model, {@code ListModel}, maintains the
      60  * contents of the list.
      61  * <p>
      62  * It's easy to display an array or Vector of objects, using the {@code JList}
      63  * constructor that automatically builds a read-only {@code ListModel} instance
      64  * for you:
      65  * <pre>
      66  * {@code
      67  * // Create a JList that displays strings from an array
      68  *
      69  * String[] data = {"one", "two", "three", "four"};
      70  * JList<String> myList = new JList<String>(data);
      71  *
      72  * // Create a JList that displays the superclasses of JList.class, by
      73  * // creating it with a Vector populated with this data
      74  *
      75  * Vector<Class<?>> superClasses = new Vector<Class<?>>();
      76  * Class<JList> rootClass = javax.swing.JList.class;
      77  * for(Class<?> cls = rootClass; cls != null; cls = cls.getSuperclass()) {
      78  *     superClasses.addElement(cls);
      79  * }
      80  * JList<Class<?>> myList = new JList<Class<?>>(superClasses);
      81  *
      82  * // The automatically created model is stored in JList's "model"
      83  * // property, which you can retrieve
      84  *
      85  * ListModel<Class<?>> model = myList.getModel();
      86  * for(int i = 0; i < model.getSize(); i++) {
      87  *     System.out.println(model.getElementAt(i));
      88  * }
      89  * }
      90  * </pre>
      91  * <p>
      92  * A {@code ListModel} can be supplied directly to a {@code JList} by way of a
      93  * constructor or the {@code setModel} method. The contents need not be static -
      94  * the number of items, and the values of items can change over time. A correct
      95  * {@code ListModel} implementation notifies the set of
      96  * {@code javax.swing.event.ListDataListener}s that have been added to it, each
      97  * time a change occurs. These changes are characterized by a
      98  * {@code javax.swing.event.ListDataEvent}, which identifies the range of list
      99  * indices that have been modified, added, or removed. {@code JList}'s
     100  * {@code ListUI} is responsible for keeping the visual representation up to
     101  * date with changes, by listening to the model.
     102  * <p>
     103  * Simple, dynamic-content, {@code JList} applications can use the
     104  * {@code DefaultListModel} class to maintain list elements. This class
     105  * implements the {@code ListModel} interface and also provides a
     106  * <code>java.util.Vector</code>-like API. Applications that need a more
     107  * custom <code>ListModel</code> implementation may instead wish to subclass
     108  * {@code AbstractListModel}, which provides basic support for managing and
     109  * notifying listeners. For example, a read-only implementation of
     110  * {@code AbstractListModel}:
     111  * <pre>
     112  * {@code
     113  * // This list model has about 2^16 elements.  Enjoy scrolling.
     114  *
     115  * ListModel<String> bigData = new AbstractListModel<String>() {
     116  *     public int getSize() { return Short.MAX_VALUE; }
     117  *     public String getElementAt(int index) { return "Index " + index; }
     118  * };
     119  * }
     120  * </pre>
     121  * <p>
     122  * The selection state of a {@code JList} is managed by another separate
     123  * model, an instance of {@code ListSelectionModel}. {@code JList} is
     124  * initialized with a selection model on construction, and also contains
     125  * methods to query or set this selection model. Additionally, {@code JList}
     126  * provides convenient methods for easily managing the selection. These methods,
     127  * such as {@code setSelectedIndex} and {@code getSelectedValue}, are cover
     128  * methods that take care of the details of interacting with the selection
     129  * model. By default, {@code JList}'s selection model is configured to allow any
     130  * combination of items to be selected at a time; selection mode
     131  * {@code MULTIPLE_INTERVAL_SELECTION}. The selection mode can be changed
     132  * on the selection model directly, or via {@code JList}'s cover method.
     133  * Responsibility for updating the selection model in response to user gestures
     134  * lies with the list's {@code ListUI}.
     135  * <p>
     136  * A correct {@code ListSelectionModel} implementation notifies the set of
     137  * {@code javax.swing.event.ListSelectionListener}s that have been added to it
     138  * each time a change to the selection occurs. These changes are characterized
     139  * by a {@code javax.swing.event.ListSelectionEvent}, which identifies the range
     140  * of the selection change.
     141  * <p>
     142  * The preferred way to listen for changes in list selection is to add
     143  * {@code ListSelectionListener}s directly to the {@code JList}. {@code JList}
     144  * then takes care of listening to the selection model and notifying your
     145  * listeners of change.
     146  * <p>
     147  * Responsibility for listening to selection changes in order to keep the list's
     148  * visual representation up to date lies with the list's {@code ListUI}.
     149  * <p>
     150  * <a id="renderer"></a>
     151  * Painting of cells in a {@code JList} is handled by a delegate called a
     152  * cell renderer, installed on the list as the {@code cellRenderer} property.
     153  * The renderer provides a {@code java.awt.Component} that is used
     154  * like a "rubber stamp" to paint the cells. Each time a cell needs to be
     155  * painted, the list's {@code ListUI} asks the cell renderer for the component,
     156  * moves it into place, and has it paint the contents of the cell by way of its
     157  * {@code paint} method. A default cell renderer, which uses a {@code JLabel}
     158  * component to render, is installed by the lists's {@code ListUI}. You can
     159  * substitute your own renderer using code like this:
     160  * <pre>
     161  * {@code
     162  *  // Display an icon and a string for each object in the list.
     163  *
     164  * class MyCellRenderer extends JLabel implements ListCellRenderer<Object> {
     165  *     static final ImageIcon longIcon = new ImageIcon("long.gif");
     166  *     static final ImageIcon shortIcon = new ImageIcon("short.gif");
     167  *
     168  *     // This is the only method defined by ListCellRenderer.
     169  *     // We just reconfigure the JLabel each time we're called.
     170  *
     171  *     public Component getListCellRendererComponent(
     172  *       JList<?> list,           // the list
     173  *       Object value,            // value to display
     174  *       int index,               // cell index
     175  *       boolean isSelected,      // is the cell selected
     176  *       boolean cellHasFocus)    // does the cell have focus
     177  *     {
     178  *         String s = value.toString();
     179  *         setText(s);
     180  *         setIcon((s.length() > 10) ? longIcon : shortIcon);
     181  *         if (isSelected) {
     182  *             setBackground(list.getSelectionBackground());
     183  *             setForeground(list.getSelectionForeground());
     184  *         } else {
     185  *             setBackground(list.getBackground());
     186  *             setForeground(list.getForeground());
     187  *         }
     188  *         setEnabled(list.isEnabled());
     189  *         setFont(list.getFont());
     190  *         setOpaque(true);
     191  *         return this;
     192  *     }
     193  * }
     194  *
     195  * myList.setCellRenderer(new MyCellRenderer());
     196  * }
     197  * </pre>
     198  * <p>
     199  * Another job for the cell renderer is in helping to determine sizing
     200  * information for the list. By default, the list's {@code ListUI} determines
     201  * the size of cells by asking the cell renderer for its preferred
     202  * size for each list item. This can be expensive for large lists of items.
     203  * To avoid these calculations, you can set a {@code fixedCellWidth} and
     204  * {@code fixedCellHeight} on the list, or have these values calculated
     205  * automatically based on a single prototype value:
     206  * <a id="prototype_example"></a>
     207  * <pre>
     208  * {@code
     209  * JList<String> bigDataList = new JList<String>(bigData);
     210  *
     211  * // We don't want the JList implementation to compute the width
     212  * // or height of all of the list cells, so we give it a string
     213  * // that's as big as we'll need for any cell.  It uses this to
     214  * // compute values for the fixedCellWidth and fixedCellHeight
     215  * // properties.
     216  *
     217  * bigDataList.setPrototypeCellValue("Index 1234567890");
     218  * }
     219  * </pre>
     220  * <p>
     221  * {@code JList} doesn't implement scrolling directly. To create a list that
     222  * scrolls, make it the viewport view of a {@code JScrollPane}. For example:
     223  * <pre>
     224  * JScrollPane scrollPane = new JScrollPane(myList);
     225  *
     226  * // Or in two steps:
     227  * JScrollPane scrollPane = new JScrollPane();
     228  * scrollPane.getViewport().setView(myList);
     229  * </pre>
     230  * <p>
     231  * {@code JList} doesn't provide any special handling of double or triple
     232  * (or N) mouse clicks, but it's easy to add a {@code MouseListener} if you
     233  * wish to take action on these events. Use the {@code locationToIndex}
     234  * method to determine what cell was clicked. For example:
     235  * <pre>
     236  * MouseListener mouseListener = new MouseAdapter() {
     237  *     public void mouseClicked(MouseEvent e) {
     238  *         if (e.getClickCount() == 2) {
     239  *             int index = list.locationToIndex(e.getPoint());
     240  *             System.out.println("Double clicked on Item " + index);
     241  *          }
     242  *     }
     243  * };
     244  * list.addMouseListener(mouseListener);
     245  * </pre>
     246  * <p>
     247  * <strong>Warning:</strong> Swing is not thread safe. For more
     248  * information see <a
     249  * href="package-summary.html#threading">Swing's Threading
     250  * Policy</a>.
     251  * <p>
     252  * <strong>Warning:</strong>
     253  * Serialized objects of this class will not be compatible with
     254  * future Swing releases. The current serialization support is
     255  * appropriate for short term storage or RMI between applications running
     256  * the same version of Swing.  As of 1.4, support for long term storage
     257  * of all JavaBeans&trade;
     258  * has been added to the <code>java.beans</code> package.
     259  * Please see {@link java.beans.XMLEncoder}.
     260  * <p>
     261  * See <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/list.html">How to Use Lists</a>
     262  * in <a href="http://docs.oracle.com/javase/tutorial/"><em>The Java Tutorial</em></a>
     263  * for further documentation.
     264  *
     265  * @see ListModel
     266  * @see AbstractListModel
     267  * @see DefaultListModel
     268  * @see ListSelectionModel
     269  * @see DefaultListSelectionModel
     270  * @see ListCellRenderer
     271  * @see DefaultListCellRenderer
     272  *
     273  * @param <E> the type of the elements of this list
     274  *
     275  * @author Hans Muller
     276  * @since 1.2
     277  */
     278 @JavaBean(defaultProperty = "UI", description = "A component which allows for the selection of one or more objects from a list.")
     279 @SwingContainer(false)
     280 @SuppressWarnings("serial") // Same-version serialization only
     281 public class JList<E> extends JComponent implements Scrollable, Accessible
     282 {
     283     /**
     284      * @see #getUIClassID
     285      * @see #readObject
     286      */
     287     private static final String uiClassID = "ListUI";
     288
     289     /**
     290      * Indicates a vertical layout of cells, in a single column;
     291      * the default layout.
     292      * @see #setLayoutOrientation
     293      * @since 1.4
     294      */
     295     public static final int VERTICAL = 0;
     296
     297     /**
     298      * Indicates a "newspaper style" layout with cells flowing vertically
     299      * then horizontally.
     300      * @see #setLayoutOrientation
     301      * @since 1.4
     302      */
     303     public static final int VERTICAL_WRAP = 1;
     304
     305     /**
     306      * Indicates a "newspaper style" layout with cells flowing horizontally
     307      * then vertically.
     308      * @see #setLayoutOrientation
     309      * @since 1.4
     310      */
     311     public static final int HORIZONTAL_WRAP = 2;
     312
     313     private int fixedCellWidth = -1;
     314     private int fixedCellHeight = -1;
     315     private int horizontalScrollIncrement = -1;
     316     private E prototypeCellValue;
     317     private int visibleRowCount = 8;
     318     private Color selectionForeground;
     319     private Color selectionBackground;
     320     private boolean dragEnabled;
     321
     322     private ListSelectionModel selectionModel;
     323     private ListModel<E> dataModel;
     324     private ListCellRenderer<? super E> cellRenderer;
     325     private ListSelectionListener selectionListener;
     326
     327     /**
     328      * How to lay out the cells; defaults to <code>VERTICAL</code>.
     329      */
     330     private int layoutOrientation;
     331
     332     /**
     333      * The drop mode for this component.
     334      */
     335     private DropMode dropMode = DropMode.USE_SELECTION;
     336
     337     /**
     338      * The drop location.
     339      */
     340     private transient DropLocation dropLocation;
     341
     342     /**
     343      * Flag to indicate UI update is in progress
     344      */
     345     private transient boolean updateInProgress;
     346
     347     /**
     348      * A subclass of <code>TransferHandler.DropLocation</code> representing
     349      * a drop location for a <code>JList</code>.
     350      *
     351      * @see #getDropLocation
     352      * @since 1.6
     353      */
     354     public static final class DropLocation extends TransferHandler.DropLocation {
     355         private final int index;
     356         private final boolean isInsert;
     357
     358         private DropLocation(Point p, int index, boolean isInsert) {
     359             super(p);
     360             this.index = index;
     361             this.isInsert = isInsert;
     362         }
     363
     364         /**
     365          * Returns the index where dropped data should be placed in the
     366          * list. Interpretation of the value depends on the drop mode set on
     367          * the associated component. If the drop mode is either
     368          * <code>DropMode.USE_SELECTION</code> or <code>DropMode.ON</code>,
     369          * the return value is an index of a row in the list. If the drop mode is
     370          * <code>DropMode.INSERT</code>, the return value refers to the index
     371          * where the data should be inserted. If the drop mode is
     372          * <code>DropMode.ON_OR_INSERT</code>, the value of
     373          * <code>isInsert()</code> indicates whether the index is an index
     374          * of a row, or an insert index.
     375          * <p>
     376          * <code>-1</code> indicates that the drop occurred over empty space,
     377          * and no index could be calculated.
     378          *
     379          * @return the drop index
     380          */
     381         public int getIndex() {
     382             return index;
     383         }
     384
     385         /**
     386          * Returns whether or not this location represents an insert
     387          * location.
     388          *
     389          * @return whether or not this is an insert location
     390          */
     391         public boolean isInsert() {
     392             return isInsert;
     393         }
     394
     395         /**
     396          * Returns a string representation of this drop location.
     397          * This method is intended to be used for debugging purposes,
     398          * and the content and format of the returned string may vary
     399          * between implementations.
     400          *
     401          * @return a string representation of this drop location
     402          */
     403         public String toString() {
     404             return getClass().getName()
     405                    + "[dropPoint=" + getDropPoint() + ","
     406                    + "index=" + index + ","
     407                    + "insert=" + isInsert + "]";
     408         }
     409     }
     410
     411     /**
     412      * Constructs a {@code JList} that displays elements from the specified,
     413      * {@code non-null}, model. All {@code JList} constructors delegate to
     414      * this one.
     415      * <p>
     416      * This constructor registers the list with the {@code ToolTipManager},
     417      * allowing for tooltips to be provided by the cell renderers.
     418      *
     419      * @param dataModel the model for the list
     420      * @exception IllegalArgumentException if the model is {@code null}
     421      */
     422     public JList(ListModel<E> dataModel)
     423     {
     424         if (dataModel == null) {
     425             throw new IllegalArgumentException("dataModel must be non null");
     426         }
     427
     428         // Register with the ToolTipManager so that tooltips from the
     429         // renderer show through.
     430         ToolTipManager toolTipManager = ToolTipManager.sharedInstance();
     431         toolTipManager.registerComponent(this);
     432
     433         layoutOrientation = VERTICAL;
     434
     435         this.dataModel = dataModel;
     436         selectionModel = createSelectionModel();
     437         setAutoscrolls(true);
     438         setOpaque(true);
     439         updateUI();
     440     }
     441
     442
     443     /**
     444      * Constructs a <code>JList</code> that displays the elements in
     445      * the specified array. This constructor creates a read-only model
     446      * for the given array, and then delegates to the constructor that
     447      * takes a {@code ListModel}.
     448      * <p>
     449      * Attempts to pass a {@code null} value to this method results in
     450      * undefined behavior and, most likely, exceptions. The created model
     451      * references the given array directly. Attempts to modify the array
     452      * after constructing the list results in undefined behavior.
     453      *
     454      * @param  listData  the array of Objects to be loaded into the data model,
     455      *                   {@code non-null}
     456      */
     457     public JList(final E[] listData)
     458     {
     459         this (
     460             new AbstractListModel<E>() {
     461                 public int getSize() { return listData.length; }
     462                 public E getElementAt(int i) { return listData[i]; }
     463             }
     464         );
     465     }
     466
     467
     468     /**
     469      * Constructs a <code>JList</code> that displays the elements in
     470      * the specified <code>Vector</code>. This constructor creates a read-only
     471      * model for the given {@code Vector}, and then delegates to the constructor
     472      * that takes a {@code ListModel}.
     473      * <p>
     474      * Attempts to pass a {@code null} value to this method results in
     475      * undefined behavior and, most likely, exceptions. The created model
     476      * references the given {@code Vector} directly. Attempts to modify the
     477      * {@code Vector} after constructing the list results in undefined behavior.
     478      *
     479      * @param  listData  the <code>Vector</code> to be loaded into the
     480      *                   data model, {@code non-null}
     481      */
     482     public JList(final Vector<? extends E> listData) {
     483         this (
     484             new AbstractListModel<E>() {
     485                 public int getSize() { return listData.size(); }
     486                 public E getElementAt(int i) { return listData.elementAt(i); }
     487             }
     488         );
     489     }
     490
     491
     492     /**
     493      * Constructs a <code>JList</code> with an empty, read-only, model.
     494      */
     495     public JList() {
     496         this (
     497             new AbstractListModel<E>() {
     498               public int getSize() { return 0; }
     499               public E getElementAt(int i) { throw new IndexOutOfBoundsException("No Data Model"); }
     500             }
     501         );
     502     }
     503
     504
     505     /**
     506      * Returns the {@code ListUI}, the look and feel object that
     507      * renders this component.
     508      *
     509      * @return the <code>ListUI</code> object that renders this component
     510      */
     511     public ListUI getUI() {
     512         return (ListUI)ui;
     513     }
     514
     515
     516     /**
     517      * Sets the {@code ListUI}, the look and feel object that
     518      * renders this component.
     519      *
     520      * @param ui  the <code>ListUI</code> object
     521      * @see UIDefaults#getUI
     522      */
     523     @BeanProperty(hidden = true, visualUpdate = true, description
     524             = "The UI object that implements the Component's LookAndFeel.")
     525     public void setUI(ListUI ui) {
     526         super.setUI(ui);
     527     }
     528
     529
     530     /**
     531      * Resets the {@code ListUI} property by setting it to the value provided
     532      * by the current look and feel. If the current cell renderer was installed
     533      * by the developer (rather than the look and feel itself), this also causes
     534      * the cell renderer and its children to be updated, by calling
     535      * {@code SwingUtilities.updateComponentTreeUI} on it.
     536      *
     537      * @see UIManager#getUI
     538      * @see SwingUtilities#updateComponentTreeUI
     539      */
     540     public void updateUI() {
     541         if (!updateInProgress) {
     542             updateInProgress = true;
     543             try {
     544                 setUI((ListUI)UIManager.getUI(this));
     545
     546                 ListCellRenderer<? super E> renderer = getCellRenderer();
     547                 if (renderer instanceof Component) {
     548                     SwingUtilities.updateComponentTreeUI((Component)renderer);
     549                 }
     550             } finally {
     551                 updateInProgress = false;
     552             }
     553         }
     554     }
     555
     556
     557     /**
     558      * Returns {@code "ListUI"}, the <code>UIDefaults</code> key used to look
     559      * up the name of the {@code javax.swing.plaf.ListUI} class that defines
     560      * the look and feel for this component.
     561      *
     562      * @return the string "ListUI"
     563      * @see JComponent#getUIClassID
     564      * @see UIDefaults#getUI
     565      */
     566     @BeanProperty(bound = false)
     567     public String getUIClassID() {
     568         return uiClassID;
     569     }
     570
     571
     572     /* -----private-----
     573      * This method is called by setPrototypeCellValue and setCellRenderer
     574      * to update the fixedCellWidth and fixedCellHeight properties from the
     575      * current value of prototypeCellValue (if it's non null).
     576      * <p>
     577      * This method sets fixedCellWidth and fixedCellHeight but does <b>not</b>
     578      * generate PropertyChangeEvents for them.
     579      *
     580      * @see #setPrototypeCellValue
     581      * @see #setCellRenderer
     582      */
     583     private void updateFixedCellSize()
     584     {
     585         ListCellRenderer<? super E> cr = getCellRenderer();
     586         E value = getPrototypeCellValue();
     587
     588         if ((cr != null) && (value != null)) {
     589             Component c = cr.getListCellRendererComponent(this, value, 0, false, false);
     590
     591             /* The ListUI implementation will add Component c to its private
     592              * CellRendererPane however we can't assume that's already
     593              * been done here.  So we temporarily set the one "inherited"
     594              * property that may affect the renderer components preferred size:
     595              * its font.
     596              */
     597             Font f = c.getFont();
     598             c.setFont(getFont());
     599
     600             Dimension d = c.getPreferredSize();
     601             fixedCellWidth = d.width;
     602             fixedCellHeight = d.height;
     603
     604             c.setFont(f);
     605         }
     606     }
     607
     608
     609     /**
     610      * Returns the "prototypical" cell value -- a value used to calculate a
     611      * fixed width and height for cells. This can be {@code null} if there
     612      * is no such value.
     613      *
     614      * @return the value of the {@code prototypeCellValue} property
     615      * @see #setPrototypeCellValue
     616      */
     617     public E getPrototypeCellValue() {
     618         return prototypeCellValue;
     619     }
     620
     621     /**
     622      * Sets the {@code prototypeCellValue} property, and then (if the new value
     623      * is {@code non-null}), computes the {@code fixedCellWidth} and
     624      * {@code fixedCellHeight} properties by requesting the cell renderer
     625      * component for the given value (and index 0) from the cell renderer, and
     626      * using that component's preferred size.
     627      * <p>
     628      * This method is useful when the list is too long to allow the
     629      * {@code ListUI} to compute the width/height of each cell, and there is a
     630      * single cell value that is known to occupy as much space as any of the
     631      * others, a so-called prototype.
     632      * <p>
     633      * While all three of the {@code prototypeCellValue},
     634      * {@code fixedCellHeight}, and {@code fixedCellWidth} properties may be
     635      * modified by this method, {@code PropertyChangeEvent} notifications are
     636      * only sent when the {@code prototypeCellValue} property changes.
     637      * <p>
     638      * To see an example which sets this property, see the
     639      * <a href="#prototype_example">class description</a> above.
     640      * <p>
     641      * The default value of this property is <code>null</code>.
     642      * <p>
     643      * This is a JavaBeans bound property.
     644      *
     645      * @param prototypeCellValue  the value on which to base
     646      *                          <code>fixedCellWidth</code> and
     647      *                          <code>fixedCellHeight</code>
     648      * @see #getPrototypeCellValue
     649      * @see #setFixedCellWidth
     650      * @see #setFixedCellHeight
     651      * @see JComponent#addPropertyChangeListener
     652      */
     653     @BeanProperty(visualUpdate = true, description
     654             = "The cell prototype value, used to compute cell width and height.")
     655     public void setPrototypeCellValue(E prototypeCellValue) {
     656         E oldValue = this.prototypeCellValue;
     657         this.prototypeCellValue = prototypeCellValue;
     658
     659         /* If the prototypeCellValue has changed and is non-null,
     660          * then recompute fixedCellWidth and fixedCellHeight.
     661          */
     662
     663         if ((prototypeCellValue != null) && !prototypeCellValue.equals(oldValue)) {
     664             updateFixedCellSize();
     665         }
     666
     667         firePropertyChange("prototypeCellValue", oldValue, prototypeCellValue);
     668     }
     669
     670
     671     /**
     672      * Returns the value of the {@code fixedCellWidth} property.
     673      *
     674      * @return the fixed cell width
     675      * @see #setFixedCellWidth
     676      */
     677     public int getFixedCellWidth() {
     678         return fixedCellWidth;
     679     }
     680
     681     /**
     682      * Sets a fixed value to be used for the width of every cell in the list.
     683      * If {@code width} is -1, cell widths are computed in the {@code ListUI}
     684      * by applying <code>getPreferredSize</code> to the cell renderer component
     685      * for each list element.
     686      * <p>
     687      * The default value of this property is {@code -1}.
     688      * <p>
     689      * This is a JavaBeans bound property.
     690      *
     691      * @param width the width to be used for all cells in the list
     692      * @see #setPrototypeCellValue
     693      * @see #setFixedCellWidth
     694      * @see JComponent#addPropertyChangeListener
     695      */
     696     @BeanProperty(visualUpdate = true, description
     697             = "Defines a fixed cell width when greater than zero.")
     698     public void setFixedCellWidth(int width) {
     699         int oldValue = fixedCellWidth;
     700         fixedCellWidth = width;
     701         firePropertyChange("fixedCellWidth", oldValue, fixedCellWidth);
     702     }
     703
     704
     705     /**
     706      * Returns the value of the {@code fixedCellHeight} property.
     707      *
     708      * @return the fixed cell height
     709      * @see #setFixedCellHeight
     710      */
     711     public int getFixedCellHeight() {
     712         return fixedCellHeight;
     713     }
     714
     715     /**
     716      * Sets a fixed value to be used for the height of every cell in the list.
     717      * If {@code height} is -1, cell heights are computed in the {@code ListUI}
     718      * by applying <code>getPreferredSize</code> to the cell renderer component
     719      * for each list element.
     720      * <p>
     721      * The default value of this property is {@code -1}.
     722      * <p>
     723      * This is a JavaBeans bound property.
     724      *
     725      * @param height the height to be used for all cells in the list
     726      * @see #setPrototypeCellValue
     727      * @see #setFixedCellWidth
     728      * @see JComponent#addPropertyChangeListener
     729      */
     730     @BeanProperty(visualUpdate = true, description
     731             = "Defines a fixed cell height when greater than zero.")
     732     public void setFixedCellHeight(int height) {
     733         int oldValue = fixedCellHeight;
     734         fixedCellHeight = height;
     735         firePropertyChange("fixedCellHeight", oldValue, fixedCellHeight);
     736     }
     737
     738
     739     /**
     740      * Returns the object responsible for painting list items.
     741      *
     742      * @return the value of the {@code cellRenderer} property
     743      * @see #setCellRenderer
     744      */
     745     @Transient
     746     public ListCellRenderer<? super E> getCellRenderer() {
     747         return cellRenderer;
     748     }
     749
     750     /**
     751      * Sets the delegate that is used to paint each cell in the list.
     752      * The job of a cell renderer is discussed in detail in the
     753      * <a href="#renderer">class level documentation</a>.
     754      * <p>
     755      * If the {@code prototypeCellValue} property is {@code non-null},
     756      * setting the cell renderer also causes the {@code fixedCellWidth} and
     757      * {@code fixedCellHeight} properties to be re-calculated. Only one
     758      * <code>PropertyChangeEvent</code> is generated however -
     759      * for the <code>cellRenderer</code> property.
     760      * <p>
     761      * The default value of this property is provided by the {@code ListUI}
     762      * delegate, i.e. by the look and feel implementation.
     763      * <p>
     764      * This is a JavaBeans bound property.
     765      *
     766      * @param cellRenderer the <code>ListCellRenderer</code>
     767      *                          that paints list cells
     768      * @see #getCellRenderer
     769      */
     770     @BeanProperty(visualUpdate = true, description
     771             = "The component used to draw the cells.")
     772     public void setCellRenderer(ListCellRenderer<? super E> cellRenderer) {
     773         ListCellRenderer<? super E> oldValue = this.cellRenderer;
     774         this.cellRenderer = cellRenderer;
     775
     776         /* If the cellRenderer has changed and prototypeCellValue
     777          * was set, then recompute fixedCellWidth and fixedCellHeight.
     778          */
     779         if ((cellRenderer != null) && !cellRenderer.equals(oldValue)) {
     780             updateFixedCellSize();
     781         }
     782
     783         firePropertyChange("cellRenderer", oldValue, cellRenderer);
     784     }
     785
     786
     787     /**
     788      * Returns the color used to draw the foreground of selected items.
     789      * {@code DefaultListCellRenderer} uses this color to draw the foreground
     790      * of items in the selected state, as do the renderers installed by most
     791      * {@code ListUI} implementations.
     792      *
     793      * @return the color to draw the foreground of selected items
     794      * @see #setSelectionForeground
     795      * @see DefaultListCellRenderer
     796      */
     797     public Color getSelectionForeground() {
     798         return selectionForeground;
     799     }
     800
     801
     802     /**
     803      * Sets the color used to draw the foreground of selected items, which
     804      * cell renderers can use to render text and graphics.
     805      * {@code DefaultListCellRenderer} uses this color to draw the foreground
     806      * of items in the selected state, as do the renderers installed by most
     807      * {@code ListUI} implementations.
     808      * <p>
     809      * The default value of this property is defined by the look and feel
     810      * implementation.
     811      * <p>
     812      * This is a JavaBeans bound property.
     813      *
     814      * @param selectionForeground  the {@code Color} to use in the foreground
     815      *                             for selected list items
     816      * @see #getSelectionForeground
     817      * @see #setSelectionBackground
     818      * @see #setForeground
     819      * @see #setBackground
     820      * @see #setFont
     821      * @see DefaultListCellRenderer
     822      */
     823     @BeanProperty(visualUpdate = true, description
     824             = "The foreground color of selected cells.")
     825     public void setSelectionForeground(Color selectionForeground) {
     826         Color oldValue = this.selectionForeground;
     827         this.selectionForeground = selectionForeground;
     828         firePropertyChange("selectionForeground", oldValue, selectionForeground);
     829     }
     830
     831
     832     /**
     833      * Returns the color used to draw the background of selected items.
     834      * {@code DefaultListCellRenderer} uses this color to draw the background
     835      * of items in the selected state, as do the renderers installed by most
     836      * {@code ListUI} implementations.
     837      *
     838      * @return the color to draw the background of selected items
     839      * @see #setSelectionBackground
     840      * @see DefaultListCellRenderer
     841      */
     842     public Color getSelectionBackground() {
     843         return selectionBackground;
     844     }
     845
     846
     847     /**
     848      * Sets the color used to draw the background of selected items, which
     849      * cell renderers can use fill selected cells.
     850      * {@code DefaultListCellRenderer} uses this color to fill the background
     851      * of items in the selected state, as do the renderers installed by most
     852      * {@code ListUI} implementations.
     853      * <p>
     854      * The default value of this property is defined by the look
     855      * and feel implementation.
     856      * <p>
     857      * This is a JavaBeans bound property.
     858      *
     859      * @param selectionBackground  the {@code Color} to use for the
     860      *                             background of selected cells
     861      * @see #getSelectionBackground
     862      * @see #setSelectionForeground
     863      * @see #setForeground
     864      * @see #setBackground
     865      * @see #setFont
     866      * @see DefaultListCellRenderer
     867      */
     868     @BeanProperty(visualUpdate = true, description
     869             = "The background color of selected cells.")
     870     public void setSelectionBackground(Color selectionBackground) {
     871         Color oldValue = this.selectionBackground;
     872         this.selectionBackground = selectionBackground;
     873         firePropertyChange("selectionBackground", oldValue, selectionBackground);
     874     }
     875
     876
     877     /**
     878      * Returns the value of the {@code visibleRowCount} property. See the
     879      * documentation for {@link #setVisibleRowCount} for details on how to
     880      * interpret this value.
     881      *
     882      * @return the value of the {@code visibleRowCount} property.
     883      * @see #setVisibleRowCount
     884      */
     885     public int getVisibleRowCount() {
     886         return visibleRowCount;
     887     }
     888
     889     /**
     890      * Sets the {@code visibleRowCount} property, which has different meanings
     891      * depending on the layout orientation: For a {@code VERTICAL} layout
     892      * orientation, this sets the preferred number of rows to display without
     893      * requiring scrolling; for other orientations, it affects the wrapping of
     894      * cells.
     895      * <p>
     896      * In {@code VERTICAL} orientation:<br>
     897      * Setting this property affects the return value of the
     898      * {@link #getPreferredScrollableViewportSize} method, which is used to
     899      * calculate the preferred size of an enclosing viewport. See that method's
     900      * documentation for more details.
     901      * <p>
     902      * In {@code HORIZONTAL_WRAP} and {@code VERTICAL_WRAP} orientations:<br>
     903      * This affects how cells are wrapped. See the documentation of
     904      * {@link #setLayoutOrientation} for more details.
     905      * <p>
     906      * The default value of this property is {@code 8}.
     907      * <p>
     908      * Calling this method with a negative value results in the property
     909      * being set to {@code 0}.
     910      * <p>
     911      * This is a JavaBeans bound property.
     912      *
     913      * @param visibleRowCount  an integer specifying the preferred number of
     914      *                         rows to display without requiring scrolling
     915      * @see #getVisibleRowCount
     916      * @see #getPreferredScrollableViewportSize
     917      * @see #setLayoutOrientation
     918      * @see JComponent#getVisibleRect
     919      * @see JViewport
     920      */
     921     @BeanProperty(visualUpdate = true, description
     922             = "The preferred number of rows to display without requiring scrolling")
     923     public void setVisibleRowCount(int visibleRowCount) {
     924         int oldValue = this.visibleRowCount;
     925         this.visibleRowCount = Math.max(0, visibleRowCount);
     926         firePropertyChange("visibleRowCount", oldValue, visibleRowCount);
     927     }
     928
     929
     930     /**
     931      * Returns the layout orientation property for the list: {@code VERTICAL}
     932      * if the layout is a single column of cells, {@code VERTICAL_WRAP} if the
     933      * layout is "newspaper style" with the content flowing vertically then
     934      * horizontally, or {@code HORIZONTAL_WRAP} if the layout is "newspaper
     935      * style" with the content flowing horizontally then vertically.
     936      *
     937      * @return the value of the {@code layoutOrientation} property
     938      * @see #setLayoutOrientation
     939      * @since 1.4
     940      */
     941     public int getLayoutOrientation() {
     942         return layoutOrientation;
     943     }
     944
     945
     946     /**
     947      * Defines the way list cells are layed out. Consider a {@code JList}
     948      * with five cells. Cells can be layed out in one of the following ways:
     949      *
     950      * <pre>
     951      * VERTICAL:          0
     952      *                    1
     953      *                    2
     954      *                    3
     955      *                    4
     956      *
     957      * HORIZONTAL_WRAP:   0  1  2
     958      *                    3  4
     959      *
     960      * VERTICAL_WRAP:     0  3
     961      *                    1  4
     962      *                    2
     963      * </pre>
     964      * <p>
     965      * A description of these layouts follows:
     966      *
     967      * <table class="striped">
     968      * <caption>Describes layouts VERTICAL,HORIZONTAL_WRAP, and VERTICAL_WRAP
     969      * </caption>
     970      * <thead>
     971      *   <tr>
     972      *     <th scope="col">Value
     973      *     <th scope="col">Description
     974      * </thead>
     975      * <tbody>
     976      *   <tr>
     977      *     <th scope="row">{@code VERTICAL}
     978      *     <td>Cells are layed out vertically in a single column.
     979      *   <tr>
     980      *     <th scope="row">{@code HORIZONTAL_WRAP}
     981      *     <td>Cells are layed out horizontally, wrapping to a new row as
     982      *     necessary. If the {@code visibleRowCount} property is less than or
     983      *     equal to zero, wrapping is determined by the width of the list;
     984      *     otherwise wrapping is done in such a way as to ensure
     985      *     {@code visibleRowCount} rows in the list.
     986      *   <tr>
     987      *     <th scope="row">{@code VERTICAL_WRAP}
     988      *     <td>Cells are layed out vertically, wrapping to a new column as
     989      *     necessary. If the {@code visibleRowCount} property is less than or
     990      *     equal to zero, wrapping is determined by the height of the list;
     991      *     otherwise wrapping is done at {@code visibleRowCount} rows.
     992      * </tbody>
     993      * </table>
     994      *
     995      * The default value of this property is <code>VERTICAL</code>.
     996      *
     997      * @param layoutOrientation the new layout orientation, one of:
     998      *        {@code VERTICAL}, {@code HORIZONTAL_WRAP} or {@code VERTICAL_WRAP}
     999      * @see #getLayoutOrientation
    1000      * @see #setVisibleRowCount
    1001      * @see #getScrollableTracksViewportHeight
    1002      * @see #getScrollableTracksViewportWidth
    1003      * @throws IllegalArgumentException if {@code layoutOrientation} isn't one of the
    1004      *         allowable values
    1005      * @since 1.4
    1006      */
    1007     @BeanProperty(visualUpdate = true, enumerationValues = {
    1008             "JList.VERTICAL",
    1009             "JList.HORIZONTAL_WRAP",
    1010             "JList.VERTICAL_WRAP"}, description
    1011             = "Defines the way list cells are layed out.")
    1012     public void setLayoutOrientation(int layoutOrientation) {
    1013         int oldValue = this.layoutOrientation;
    1014         switch (layoutOrientation) {
    1015         case VERTICAL:
    1016         case VERTICAL_WRAP:
    1017         case HORIZONTAL_WRAP:
    1018             this.layoutOrientation = layoutOrientation;
    1019             firePropertyChange("layoutOrientation", oldValue, layoutOrientation);
    1020             break;
    1021         default:
    1022             throw new IllegalArgumentException("layoutOrientation must be one of: VERTICAL, HORIZONTAL_WRAP or VERTICAL_WRAP");
    1023         }
    1024     }
    1025
    1026
    1027     /**
    1028      * Returns the smallest list index that is currently visible.
    1029      * In a left-to-right {@code componentOrientation}, the first visible
    1030      * cell is found closest to the list's upper-left corner. In right-to-left
    1031      * orientation, it is found closest to the upper-right corner.
    1032      * If nothing is visible or the list is empty, {@code -1} is returned.
    1033      * Note that the returned cell may only be partially visible.
    1034      *
    1035      * @return the index of the first visible cell
    1036      * @see #getLastVisibleIndex
    1037      * @see JComponent#getVisibleRect
    1038      */
    1039     @BeanProperty(bound = false)
    1040     public int getFirstVisibleIndex() {
    1041         Rectangle r = getVisibleRect();
    1042         int first;
    1043         if (this.getComponentOrientation().isLeftToRight()) {
    1044             first = locationToIndex(r.getLocation());
    1045         } else {
    1046             first = locationToIndex(new Point((r.x + r.width) - 1, r.y));
    1047         }
    1048         if (first != -1) {
    1049             Rectangle bounds = getCellBounds(first, first);
    1050             if (bounds != null) {
    1051                 SwingUtilities.computeIntersection(r.x, r.y, r.width, r.height, bounds);
    1052                 if (bounds.width == 0 || bounds.height == 0) {
    1053                     first = -1;
    1054                 }
    1055             }
    1056         }
    1057         return first;
    1058     }
    1059
    1060
    1061     /**
    1062      * Returns the largest list index that is currently visible.
    1063      * If nothing is visible or the list is empty, {@code -1} is returned.
    1064      * Note that the returned cell may only be partially visible.
    1065      *
    1066      * @return the index of the last visible cell
    1067      * @see #getFirstVisibleIndex
    1068      * @see JComponent#getVisibleRect
    1069      */
    1070     @BeanProperty(bound = false)
    1071     public int getLastVisibleIndex() {
    1072         boolean leftToRight = this.getComponentOrientation().isLeftToRight();
    1073         Rectangle r = getVisibleRect();
    1074         Point lastPoint;
    1075         if (leftToRight) {
    1076             lastPoint = new Point((r.x + r.width) - 1, (r.y + r.height) - 1);
    1077         } else {
    1078             lastPoint = new Point(r.x, (r.y + r.height) - 1);
    1079         }
    1080         int location = locationToIndex(lastPoint);
    1081
    1082         if (location != -1) {
    1083             Rectangle bounds = getCellBounds(location, location);
    1084
    1085             if (bounds != null) {
    1086                 SwingUtilities.computeIntersection(r.x, r.y, r.width, r.height, bounds);
    1087                 if (bounds.width == 0 || bounds.height == 0) {
    1088                     // Try the top left(LTR) or top right(RTL) corner, and
    1089                     // then go across checking each cell for HORIZONTAL_WRAP.
    1090                     // Try the lower left corner, and then go across checking
    1091                     // each cell for other list layout orientation.
    1092                     boolean isHorizontalWrap =
    1093                         (getLayoutOrientation() == HORIZONTAL_WRAP);
    1094                     Point visibleLocation = isHorizontalWrap ?
    1095                         new Point(lastPoint.x, r.y) :
    1096                         new Point(r.x, lastPoint.y);
    1097                     int last;
    1098                     int visIndex = -1;
    1099                     int lIndex = location;
    1100                     location = -1;
    1101
    1102                     do {
    1103                         last = visIndex;
    1104                         visIndex = locationToIndex(visibleLocation);
    1105
    1106                         if (visIndex != -1) {
    1107                             bounds = getCellBounds(visIndex, visIndex);
    1108                             if (visIndex != lIndex && bounds != null &&
    1109                                 bounds.contains(visibleLocation)) {
    1110                                 location = visIndex;
    1111                                 if (isHorizontalWrap) {
    1112                                     visibleLocation.y = bounds.y + bounds.height;
    1113                                     if (visibleLocation.y >= lastPoint.y) {
    1114                                         // Past visible region, bail.
    1115                                         last = visIndex;
    1116                                     }
    1117                                 }
    1118                                 else {
    1119                                     visibleLocation.x = bounds.x + bounds.width;
    1120                                     if (visibleLocation.x >= lastPoint.x) {
    1121                                         // Past visible region, bail.
    1122                                         last = visIndex;
    1123                                     }
    1124                                 }
    1125
    1126                             }
    1127                             else {
    1128                                 last = visIndex;
    1129                             }
    1130                         }
    1131                     } while (visIndex != -1 && last != visIndex);
    1132                 }
    1133             }
    1134         }
    1135         return location;
    1136     }
    1137
    1138
    1139     /**
    1140      * Scrolls the list within an enclosing viewport to make the specified
    1141      * cell completely visible. This calls {@code scrollRectToVisible} with
    1142      * the bounds of the specified cell. For this method to work, the
    1143      * {@code JList} must be within a <code>JViewport</code>.
    1144      * <p>
    1145      * If the given index is outside the list's range of cells, this method
    1146      * results in nothing.
    1147      *
    1148      * @param index  the index of the cell to make visible
    1149      * @see JComponent#scrollRectToVisible
    1150      * @see #getVisibleRect
    1151      */
    1152     public void ensureIndexIsVisible(int index) {
    1153         Rectangle cellBounds = getCellBounds(index, index);
    1154         if (cellBounds != null) {
    1155             scrollRectToVisible(cellBounds);
    1156         }
    1157     }
    1158
    1159     /**
    1160      * Turns on or off automatic drag handling. In order to enable automatic
    1161      * drag handling, this property should be set to {@code true}, and the
    1162      * list's {@code TransferHandler} needs to be {@code non-null}.
    1163      * The default value of the {@code dragEnabled} property is {@code false}.
    1164      * <p>
    1165      * The job of honoring this property, and recognizing a user drag gesture,
    1166      * lies with the look and feel implementation, and in particular, the list's
    1167      * {@code ListUI}. When automatic drag handling is enabled, most look and
    1168      * feels (including those that subclass {@code BasicLookAndFeel}) begin a
    1169      * drag and drop operation whenever the user presses the mouse button over
    1170      * an item and then moves the mouse a few pixels. Setting this property to
    1171      * {@code true} can therefore have a subtle effect on how selections behave.
    1172      * <p>
    1173      * If a look and feel is used that ignores this property, you can still
    1174      * begin a drag and drop operation by calling {@code exportAsDrag} on the
    1175      * list's {@code TransferHandler}.
    1176      *
    1177      * @param b whether or not to enable automatic drag handling
    1178      * @exception HeadlessException if
    1179      *            <code>b</code> is <code>true</code> and
    1180      *            <code>GraphicsEnvironment.isHeadless()</code>
    1181      *            returns <code>true</code>
    1182      * @see java.awt.GraphicsEnvironment#isHeadless
    1183      * @see #getDragEnabled
    1184      * @see #setTransferHandler
    1185      * @see TransferHandler
    1186      * @since 1.4
    1187      */
    1188     @BeanProperty(bound = false, description
    1189             = "determines whether automatic drag handling is enabled")
    1190     public void setDragEnabled(boolean b) {
    1191         if (b && GraphicsEnvironment.isHeadless()) {
    1192             throw new HeadlessException();
    1193         }
    1194         dragEnabled = b;
    1195     }
    1196
    1197     /**
    1198      * Returns whether or not automatic drag handling is enabled.
    1199      *
    1200      * @return the value of the {@code dragEnabled} property
    1201      * @see #setDragEnabled
    1202      * @since 1.4
    1203      */
    1204     public boolean getDragEnabled() {
    1205         return dragEnabled;
    1206     }
    1207
    1208     /**
    1209      * Sets the drop mode for this component. For backward compatibility,
    1210      * the default for this property is <code>DropMode.USE_SELECTION</code>.
    1211      * Usage of one of the other modes is recommended, however, for an
    1212      * improved user experience. <code>DropMode.ON</code>, for instance,
    1213      * offers similar behavior of showing items as selected, but does so without
    1214      * affecting the actual selection in the list.
    1215      * <p>
    1216      * <code>JList</code> supports the following drop modes:
    1217      * <ul>
    1218      *    <li><code>DropMode.USE_SELECTION</code></li>
    1219      *    <li><code>DropMode.ON</code></li>
    1220      *    <li><code>DropMode.INSERT</code></li>
    1221      *    <li><code>DropMode.ON_OR_INSERT</code></li>
    1222      * </ul>
    1223      * The drop mode is only meaningful if this component has a
    1224      * <code>TransferHandler</code> that accepts drops.
    1225      *
    1226      * @param dropMode the drop mode to use
    1227      * @throws IllegalArgumentException if the drop mode is unsupported
    1228      *         or <code>null</code>
    1229      * @see #getDropMode
    1230      * @see #getDropLocation
    1231      * @see #setTransferHandler
    1232      * @see TransferHandler
    1233      * @since 1.6
    1234      */
    1235     public final void setDropMode(DropMode dropMode) {
    1236         if (dropMode != null) {
    1237             switch (dropMode) {
    1238                 case USE_SELECTION:
    1239                 case ON:
    1240                 case INSERT:
    1241                 case ON_OR_INSERT:
    1242                     this.dropMode = dropMode;
    1243                     return;
    1244             }
    1245         }
    1246
    1247         throw new IllegalArgumentException(dropMode + ": Unsupported drop mode for list");
    1248     }
    1249
    1250     /**
    1251      * Returns the drop mode for this component.
    1252      *
    1253      * @return the drop mode for this component
    1254      * @see #setDropMode
    1255      * @since 1.6
    1256      */
    1257     public final DropMode getDropMode() {
    1258         return dropMode;
    1259     }
    1260
    1261     /**
    1262      * Calculates a drop location in this component, representing where a
    1263      * drop at the given point should insert data.
    1264      *
    1265      * @param p the point to calculate a drop location for
    1266      * @return the drop location, or <code>null</code>
    1267      */
    1268     DropLocation dropLocationForPoint(Point p) {
    1269         DropLocation location = null;
    1270         Rectangle rect = null;
    1271
    1272         int index = locationToIndex(p);
    1273         if (index != -1) {
    1274             rect = getCellBounds(index, index);
    1275         }
    1276
    1277         switch(dropMode) {
    1278             case USE_SELECTION:
    1279             case ON:
    1280                 location = new DropLocation(p,
    1281                     (rect != null && rect.contains(p)) ? index : -1,
    1282                     false);
    1283
    1284                 break;
    1285             case INSERT:
    1286                 if (index == -1) {
    1287                     location = new DropLocation(p, getModel().getSize(), true);
    1288                     break;
    1289                 }
    1290
    1291                 if (layoutOrientation == HORIZONTAL_WRAP) {
    1292                     boolean ltr = getComponentOrientation().isLeftToRight();
    1293
    1294                     if (SwingUtilities2.liesInHorizontal(rect, p, ltr, false) == TRAILING) {
    1295                         index++;
    1296                     // special case for below all cells
    1297                     } else if (index == getModel().getSize() - 1 && p.y >= rect.y + rect.height) {
    1298                         index++;
    1299                     }
    1300                 } else {
    1301                     if (SwingUtilities2.liesInVertical(rect, p, false) == TRAILING) {
    1302                         index++;
    1303                     }
    1304                 }
    1305
    1306                 location = new DropLocation(p, index, true);
    1307
    1308                 break;
    1309             case ON_OR_INSERT:
    1310                 if (index == -1) {
    1311                     location = new DropLocation(p, getModel().getSize(), true);
    1312                     break;
    1313                 }
    1314
    1315                 boolean between = false;
    1316
    1317                 if (layoutOrientation == HORIZONTAL_WRAP) {
    1318                     boolean ltr = getComponentOrientation().isLeftToRight();
    1319
    1320                     Section section = SwingUtilities2.liesInHorizontal(rect, p, ltr, true);
    1321                     if (section == TRAILING) {
    1322                         index++;
    1323                         between = true;
    1324                     // special case for below all cells
    1325                     } else if (index == getModel().getSize() - 1 && p.y >= rect.y + rect.height) {
    1326                         index++;
    1327                         between = true;
    1328                     } else if (section == LEADING) {
    1329                         between = true;
    1330                     }
    1331                 } else {
    1332                     Section section = SwingUtilities2.liesInVertical(rect, p, true);
    1333                     if (section == LEADING) {
    1334                         between = true;
    1335                     } else if (section == TRAILING) {
    1336                         index++;
    1337                         between = true;
    1338                     }
    1339                 }
    1340
    1341                 location = new DropLocation(p, index, between);
    1342
    1343                 break;
    1344             default:
    1345                 assert false : "Unexpected drop mode";
    1346         }
    1347
    1348         return location;
    1349     }
    1350
    1351     /**
    1352      * Called to set or clear the drop location during a DnD operation.
    1353      * In some cases, the component may need to use it's internal selection
    1354      * temporarily to indicate the drop location. To help facilitate this,
    1355      * this method returns and accepts as a parameter a state object.
    1356      * This state object can be used to store, and later restore, the selection
    1357      * state. Whatever this method returns will be passed back to it in
    1358      * future calls, as the state parameter. If it wants the DnD system to
    1359      * continue storing the same state, it must pass it back every time.
    1360      * Here's how this is used:
    1361      * <p>
    1362      * Let's say that on the first call to this method the component decides
    1363      * to save some state (because it is about to use the selection to show
    1364      * a drop index). It can return a state object to the caller encapsulating
    1365      * any saved selection state. On a second call, let's say the drop location
    1366      * is being changed to something else. The component doesn't need to
    1367      * restore anything yet, so it simply passes back the same state object
    1368      * to have the DnD system continue storing it. Finally, let's say this
    1369      * method is messaged with <code>null</code>. This means DnD
    1370      * is finished with this component for now, meaning it should restore
    1371      * state. At this point, it can use the state parameter to restore
    1372      * said state, and of course return <code>null</code> since there's
    1373      * no longer anything to store.
    1374      *
    1375      * @param location the drop location (as calculated by
    1376      *        <code>dropLocationForPoint</code>) or <code>null</code>
    1377      *        if there's no longer a valid drop location
    1378      * @param state the state object saved earlier for this component,
    1379      *        or <code>null</code>
    1380      * @param forDrop whether or not the method is being called because an
    1381      *        actual drop occurred
    1382      * @return any saved state for this component, or <code>null</code> if none
    1383      */
    1384     Object setDropLocation(TransferHandler.DropLocation location,
    1385                            Object state,
    1386                            boolean forDrop) {
    1387
    1388         Object retVal = null;
    1389         DropLocation listLocation = (DropLocation)location;
    1390
    1391         if (dropMode == DropMode.USE_SELECTION) {
    1392             if (listLocation == null) {
    1393                 if (!forDrop && state != null) {
    1394                     setSelectedIndices(((int[][])state)[0]);
    1395
    1396                     int anchor = ((int[][])state)[1][0];
    1397                     int lead = ((int[][])state)[1][1];
    1398
    1399                     SwingUtilities2.setLeadAnchorWithoutSelection(
    1400                             getSelectionModel(), lead, anchor);
    1401                 }
    1402             } else {
    1403                 if (dropLocation == null) {
    1404                     int[] inds = getSelectedIndices();
    1405                     retVal = new int[][] {inds, {getAnchorSelectionIndex(),
    1406                                                  getLeadSelectionIndex()}};
    1407                 } else {
    1408                     retVal = state;
    1409                 }
    1410
    1411                 int index = listLocation.getIndex();
    1412                 if (index == -1) {
    1413                     clearSelection();
    1414                     getSelectionModel().setAnchorSelectionIndex(-1);
    1415                     getSelectionModel().setLeadSelectionIndex(-1);
    1416                 } else {
    1417                     setSelectionInterval(index, index);
    1418                 }
    1419             }
    1420         }
    1421
    1422         DropLocation old = dropLocation;
    1423         dropLocation = listLocation;
    1424         firePropertyChange("dropLocation", old, dropLocation);
    1425
    1426         return retVal;
    1427     }
    1428
    1429     /**
    1430      * Returns the location that this component should visually indicate
    1431      * as the drop location during a DnD operation over the component,
    1432      * or {@code null} if no location is to currently be shown.
    1433      * <p>
    1434      * This method is not meant for querying the drop location
    1435      * from a {@code TransferHandler}, as the drop location is only
    1436      * set after the {@code TransferHandler}'s <code>canImport</code>
    1437      * has returned and has allowed for the location to be shown.
    1438      * <p>
    1439      * When this property changes, a property change event with
    1440      * name "dropLocation" is fired by the component.
    1441      * <p>
    1442      * By default, responsibility for listening for changes to this property
    1443      * and indicating the drop location visually lies with the list's
    1444      * {@code ListUI}, which may paint it directly and/or install a cell
    1445      * renderer to do so. Developers wishing to implement custom drop location
    1446      * painting and/or replace the default cell renderer, may need to honor
    1447      * this property.
    1448      *
    1449      * @return the drop location
    1450      * @see #setDropMode
    1451      * @see TransferHandler#canImport(TransferHandler.TransferSupport)
    1452      * @since 1.6
    1453      */
    1454     @BeanProperty(bound = false)
    1455     public final DropLocation getDropLocation() {
    1456         return dropLocation;
    1457     }
    1458
    1459     /**
    1460      * Returns the next list element whose {@code toString} value
    1461      * starts with the given prefix.
    1462      *
    1463      * @param prefix the string to test for a match
    1464      * @param startIndex the index for starting the search
    1465      * @param bias the search direction, either
    1466      * Position.Bias.Forward or Position.Bias.Backward.
    1467      * @return the index of the next list element that
    1468      * starts with the prefix; otherwise {@code -1}
    1469      * @exception IllegalArgumentException if prefix is {@code null}
    1470      * or startIndex is out of bounds
    1471      * @since 1.4
    1472      */
    1473     public int getNextMatch(String prefix, int startIndex, Position.Bias bias) {
    1474         ListModel<E> model = getModel();
    1475         int max = model.getSize();
    1476         if (prefix == null) {
    1477             throw new IllegalArgumentException();
    1478         }
    1479         if (startIndex < 0 || startIndex >= max) {
    1480             throw new IllegalArgumentException();
    1481         }
    1482         prefix = prefix.toUpperCase();
    1483
    1484         // start search from the next element after the selected element
    1485         int increment = (bias == Position.Bias.Forward) ? 1 : -1;
    1486         int index = startIndex;
    1487         do {
    1488             E element = model.getElementAt(index);
    1489
    1490             if (element != null) {
    1491                 String string;
    1492
    1493                 if (element instanceof String) {
    1494                     string = ((String)element).toUpperCase();
    1495                 }
    1496                 else {
    1497                     string = element.toString();
    1498                     if (string != null) {
    1499                         string = string.toUpperCase();
    1500                     }
    1501                 }
    1502
    1503                 if (string != null && string.startsWith(prefix)) {
    1504                     return index;
    1505                 }
    1506             }
    1507             index = (index + increment + max) % max;
    1508         } while (index != startIndex);
    1509         return -1;
    1510     }
    1511
    1512     /**
    1513      * Returns the tooltip text to be used for the given event. This overrides
    1514      * {@code JComponent}'s {@code getToolTipText} to first check the cell
    1515      * renderer component for the cell over which the event occurred, returning
    1516      * its tooltip text, if any. This implementation allows you to specify
    1517      * tooltip text on the cell level, by using {@code setToolTipText} on your
    1518      * cell renderer component.
    1519      * <p>
    1520      * <strong>Note:</strong> For <code>JList</code> to properly display the
    1521      * tooltips of its renderers in this manner, <code>JList</code> must be a
    1522      * registered component with the <code>ToolTipManager</code>. This registration
    1523      * is done automatically in the constructor. However, if at a later point
    1524      * <code>JList</code> is unregistered, by way of a call to
    1525      * {@code setToolTipText(null)}, tips from the renderers will no longer display.
    1526      *
    1527      * @param event the {@code MouseEvent} to fetch the tooltip text for
    1528      * @see JComponent#setToolTipText
    1529      * @see JComponent#getToolTipText
    1530      */
    1531     @SuppressWarnings("deprecation")
    1532     public String getToolTipText(MouseEvent event) {
    1533         if(event != null) {
    1534             Point p = event.getPoint();
    1535             int index = locationToIndex(p);
    1536             ListCellRenderer<? super E> r = getCellRenderer();
    1537             Rectangle cellBounds;
    1538
    1539             if (index != -1 && r != null && (cellBounds =
    1540                                getCellBounds(index, index)) != null &&
    1541                                cellBounds.contains(p.x, p.y)) {
    1542                 ListSelectionModel lsm = getSelectionModel();
    1543                 Component rComponent = r.getListCellRendererComponent(
    1544                            this, getModel().getElementAt(index), index,
    1545                            lsm.isSelectedIndex(index),
    1546                            (hasFocus() && (lsm.getLeadSelectionIndex() ==
    1547                                            index)));
    1548
    1549                 if(rComponent instanceof JComponent) {
    1550                     MouseEvent      newEvent;
    1551
    1552                     p.translate(-cellBounds.x, -cellBounds.y);
    1553                     newEvent = new MouseEvent(rComponent, event.getID(),
    1554                                               event.getWhen(),
    1555                                               event.getModifiers(),
    1556                                               p.x, p.y,
    1557                                               event.getXOnScreen(),
    1558                                               event.getYOnScreen(),
    1559                                               event.getClickCount(),
    1560                                               event.isPopupTrigger(),
    1561                                               MouseEvent.NOBUTTON);
    1562                     MouseEventAccessor meAccessor =
    1563                         AWTAccessor.getMouseEventAccessor();
    1564                     meAccessor.setCausedByTouchEvent(newEvent,
    1565                         meAccessor.isCausedByTouchEvent(event));
    1566
    1567                     String tip = ((JComponent)rComponent).getToolTipText(
    1568                                               newEvent);
    1569
    1570                     if (tip != null) {
    1571                         return tip;
    1572                     }
    1573                 }
    1574             }
    1575         }
    1576         return super.getToolTipText();
    1577     }
    1578
    1579     /**
    1580      * --- ListUI Delegations ---
    1581      */
    1582
    1583
    1584     /**
    1585      * Returns the cell index closest to the given location in the list's
    1586      * coordinate system. To determine if the cell actually contains the
    1587      * specified location, compare the point against the cell's bounds,
    1588      * as provided by {@code getCellBounds}. This method returns {@code -1}
    1589      * if the model is empty
    1590      * <p>
    1591      * This is a cover method that delegates to the method of the same name
    1592      * in the list's {@code ListUI}. It returns {@code -1} if the list has
    1593      * no {@code ListUI}.
    1594      *
    1595      * @param location the coordinates of the point
    1596      * @return the cell index closest to the given location, or {@code -1}
    1597      */
    1598     public int locationToIndex(Point location) {
    1599         ListUI ui = getUI();
    1600         return (ui != null) ? ui.locationToIndex(this, location) : -1;
    1601     }
    1602
    1603
    1604     /**
    1605      * Returns the origin of the specified item in the list's coordinate
    1606      * system. This method returns {@code null} if the index isn't valid.
    1607      * <p>
    1608      * This is a cover method that delegates to the method of the same name
    1609      * in the list's {@code ListUI}. It returns {@code null} if the list has
    1610      * no {@code ListUI}.
    1611      *
    1612      * @param index the cell index
    1613      * @return the origin of the cell, or {@code null}
    1614      */
    1615     public Point indexToLocation(int index) {
    1616         ListUI ui = getUI();
    1617         return (ui != null) ? ui.indexToLocation(this, index) : null;
    1618     }
    1619
    1620
    1621     /**
    1622      * Returns the bounding rectangle, in the list's coordinate system,
    1623      * for the range of cells specified by the two indices.
    1624      * These indices can be supplied in any order.
    1625      * <p>
    1626      * If the smaller index is outside the list's range of cells, this method
    1627      * returns {@code null}. If the smaller index is valid, but the larger
    1628      * index is outside the list's range, the bounds of just the first index
    1629      * is returned. Otherwise, the bounds of the valid range is returned.
    1630      * <p>
    1631      * This is a cover method that delegates to the method of the same name
    1632      * in the list's {@code ListUI}. It returns {@code null} if the list has
    1633      * no {@code ListUI}.
    1634      *
    1635      * @param index0 the first index in the range
    1636      * @param index1 the second index in the range
    1637      * @return the bounding rectangle for the range of cells, or {@code null}
    1638      */
    1639     public Rectangle getCellBounds(int index0, int index1) {
    1640         ListUI ui = getUI();
    1641         return (ui != null) ? ui.getCellBounds(this, index0, index1) : null;
    1642     }
    1643
    1644
    1645     /**
    1646      * --- ListModel Support ---
    1647      */
    1648
    1649
    1650     /**
    1651      * Returns the data model that holds the list of items displayed
    1652      * by the <code>JList</code> component.
    1653      *
    1654      * @return the <code>ListModel</code> that provides the displayed
    1655      *                          list of items
    1656      * @see #setModel
    1657      */
    1658     public ListModel<E> getModel() {
    1659         return dataModel;
    1660     }
    1661
    1662     /**
    1663      * Sets the model that represents the contents or "value" of the
    1664      * list, notifies property change listeners, and then clears the
    1665      * list's selection.
    1666      * <p>
    1667      * This is a JavaBeans bound property.
    1668      *
    1669      * @param model  the <code>ListModel</code> that provides the
    1670      *                                          list of items for display
    1671      * @exception IllegalArgumentException  if <code>model</code> is
    1672      *                                          <code>null</code>
    1673      * @see #getModel
    1674      * @see #clearSelection
    1675      */
    1676     @BeanProperty(visualUpdate = true, description
    1677             = "The object that contains the data to be drawn by this JList.")
    1678     public void setModel(ListModel<E> model) {
    1679         if (model == null) {
    1680             throw new IllegalArgumentException("model must be non null");
    1681         }
    1682         ListModel<E> oldValue = dataModel;
    1683         dataModel = model;
    1684         firePropertyChange("model", oldValue, dataModel);
    1685         clearSelection();
    1686     }
    1687
    1688
    1689     /**
    1690      * Constructs a read-only <code>ListModel</code> from an array of items,
    1691      * and calls {@code setModel} with this model.
    1692      * <p>
    1693      * Attempts to pass a {@code null} value to this method results in
    1694      * undefined behavior and, most likely, exceptions. The created model
    1695      * references the given array directly. Attempts to modify the array
    1696      * after invoking this method results in undefined behavior.
    1697      *
    1698      * @param listData an array of {@code E} containing the items to
    1699      *        display in the list
    1700      * @see #setModel
    1701      */
    1702     public void setListData(final E[] listData) {
    1703         setModel (
    1704             new AbstractListModel<E>() {
    1705                 public int getSize() { return listData.length; }
    1706                 public E getElementAt(int i) { return listData[i]; }
    1707             }
    1708         );
    1709     }
    1710
    1711
    1712     /**
    1713      * Constructs a read-only <code>ListModel</code> from a <code>Vector</code>
    1714      * and calls {@code setModel} with this model.
    1715      * <p>
    1716      * Attempts to pass a {@code null} value to this method results in
    1717      * undefined behavior and, most likely, exceptions. The created model
    1718      * references the given {@code Vector} directly. Attempts to modify the
    1719      * {@code Vector} after invoking this method results in undefined behavior.
    1720      *
    1721      * @param listData a <code>Vector</code> containing the items to
    1722      *                                          display in the list
    1723      * @see #setModel
    1724      */
    1725     public void setListData(final Vector<? extends E> listData) {
    1726         setModel (
    1727             new AbstractListModel<E>() {
    1728                 public int getSize() { return listData.size(); }
    1729                 public E getElementAt(int i) { return listData.elementAt(i); }
    1730             }
    1731         );
    1732     }
    1733
    1734
    1735     /**
    1736      * --- ListSelectionModel delegations and extensions ---
    1737      */
    1738
    1739
    1740     /**
    1741      * Returns an instance of {@code DefaultListSelectionModel}; called
    1742      * during construction to initialize the list's selection model
    1743      * property.
    1744      *
    1745      * @return a {@code DefaultListSelecitonModel}, used to initialize
    1746      *         the list's selection model property during construction
    1747      * @see #setSelectionModel
    1748      * @see DefaultListSelectionModel
    1749      */
    1750     protected ListSelectionModel createSelectionModel() {
    1751         return new DefaultListSelectionModel();
    1752     }
    1753
    1754
    1755     /**
    1756      * Returns the current selection model. The selection model maintains the
    1757      * selection state of the list. See the class level documentation for more
    1758      * details.
    1759      *
    1760      * @return the <code>ListSelectionModel</code> that maintains the
    1761      *         list's selections
    1762      *
    1763      * @see #setSelectionModel
    1764      * @see ListSelectionModel
    1765      */
    1766     public ListSelectionModel getSelectionModel() {
    1767         return selectionModel;
    1768     }
    1769
    1770
    1771     /**
    1772      * Notifies {@code ListSelectionListener}s added directly to the list
    1773      * of selection changes made to the selection model. {@code JList}
    1774      * listens for changes made to the selection in the selection model,
    1775      * and forwards notification to listeners added to the list directly,
    1776      * by calling this method.
    1777      * <p>
    1778      * This method constructs a {@code ListSelectionEvent} with this list
    1779      * as the source, and the specified arguments, and sends it to the
    1780      * registered {@code ListSelectionListeners}.
    1781      *
    1782      * @param firstIndex the first index in the range, {@code <= lastIndex}
    1783      * @param lastIndex the last index in the range, {@code >= firstIndex}
    1784      * @param isAdjusting whether or not this is one in a series of
    1785      *        multiple events, where changes are still being made
    1786      *
    1787      * @see #addListSelectionListener
    1788      * @see #removeListSelectionListener
    1789      * @see javax.swing.event.ListSelectionEvent
    1790      * @see EventListenerList
    1791      */
    1792     protected void fireSelectionValueChanged(int firstIndex, int lastIndex,
    1793                                              boolean isAdjusting)
    1794     {
    1795         Object[] listeners = listenerList.getListenerList();
    1796         ListSelectionEvent e = null;
    1797
    1798         for (int i = listeners.length - 2; i >= 0; i -= 2) {
    1799             if (listeners[i] == ListSelectionListener.class) {
    1800                 if (e == null) {
    1801                     e = new ListSelectionEvent(this, firstIndex, lastIndex,
    1802                                                isAdjusting);
    1803                 }
    1804                 ((ListSelectionListener)listeners[i+1]).valueChanged(e);
    1805             }
    1806         }
    1807     }
    1808
    1809
    1810     /* A ListSelectionListener that forwards ListSelectionEvents from
    1811      * the selectionModel to the JList ListSelectionListeners.  The
    1812      * forwarded events only differ from the originals in that their
    1813      * source is the JList instead of the selectionModel itself.
    1814      */
    1815     private class ListSelectionHandler implements ListSelectionListener, Serializable
    1816     {
    1817         public void valueChanged(ListSelectionEvent e) {
    1818             fireSelectionValueChanged(e.getFirstIndex(),
    1819                                       e.getLastIndex(),
    1820                                       e.getValueIsAdjusting());
    1821         }
    1822     }
    1823
    1824
    1825     /**
    1826      * Adds a listener to the list, to be notified each time a change to the
    1827      * selection occurs; the preferred way of listening for selection state
    1828      * changes. {@code JList} takes care of listening for selection state
    1829      * changes in the selection model, and notifies the given listener of
    1830      * each change. {@code ListSelectionEvent}s sent to the listener have a
    1831      * {@code source} property set to this list.
    1832      *
    1833      * @param listener the {@code ListSelectionListener} to add
    1834      * @see #getSelectionModel
    1835      * @see #getListSelectionListeners
    1836      */
    1837     public void addListSelectionListener(ListSelectionListener listener)
    1838     {
    1839         if (selectionListener == null) {
    1840             selectionListener = new ListSelectionHandler();
    1841             getSelectionModel().addListSelectionListener(selectionListener);
    1842         }
    1843
    1844         listenerList.add(ListSelectionListener.class, listener);
    1845     }
    1846
    1847
    1848     /**
    1849      * Removes a selection listener from the list.
    1850      *
    1851      * @param listener the {@code ListSelectionListener} to remove
    1852      * @see #addListSelectionListener
    1853      * @see #getSelectionModel
    1854      */
    1855     public void removeListSelectionListener(ListSelectionListener listener) {
    1856         listenerList.remove(ListSelectionListener.class, listener);
    1857     }
    1858
    1859
    1860     /**
    1861      * Returns an array of all the {@code ListSelectionListener}s added
    1862      * to this {@code JList} by way of {@code addListSelectionListener}.
    1863      *
    1864      * @return all of the {@code ListSelectionListener}s on this list, or
    1865      *         an empty array if no listeners have been added
    1866      * @see #addListSelectionListener
    1867      * @since 1.4
    1868      */
    1869     @BeanProperty(bound = false)
    1870     public ListSelectionListener[] getListSelectionListeners() {
    1871         return listenerList.getListeners(ListSelectionListener.class);
    1872     }
    1873
    1874
    1875     /**
    1876      * Sets the <code>selectionModel</code> for the list to a
    1877      * non-<code>null</code> <code>ListSelectionModel</code>
    1878      * implementation. The selection model handles the task of making single
    1879      * selections, selections of contiguous ranges, and non-contiguous
    1880      * selections.
    1881      * <p>
    1882      * This is a JavaBeans bound property.
    1883      *
    1884      * @param selectionModel  the <code>ListSelectionModel</code> that
    1885      *                          implements the selections
    1886      * @exception IllegalArgumentException   if <code>selectionModel</code>
    1887      *                                          is <code>null</code>
    1888      * @see #getSelectionModel
    1889      */
    1890     @BeanProperty(description
    1891             = "The selection model, recording which cells are selected.")
    1892     public void setSelectionModel(ListSelectionModel selectionModel) {
    1893         if (selectionModel == null) {
    1894             throw new IllegalArgumentException("selectionModel must be non null");
    1895         }
    1896
    1897         /* Remove the forwarding ListSelectionListener from the old
    1898          * selectionModel, and add it to the new one, if necessary.
    1899          */
    1900         if (selectionListener != null) {
    1901             this.selectionModel.removeListSelectionListener(selectionListener);
    1902             selectionModel.addListSelectionListener(selectionListener);
    1903         }
    1904
    1905         ListSelectionModel oldValue = this.selectionModel;
    1906         this.selectionModel = selectionModel;
    1907         firePropertyChange("selectionModel", oldValue, selectionModel);
    1908     }
    1909
    1910
    1911     /**
    1912      * Sets the selection mode for the list. This is a cover method that sets
    1913      * the selection mode directly on the selection model.
    1914      * <p>
    1915      * The following list describes the accepted selection modes:
    1916      * <ul>
    1917      * <li>{@code ListSelectionModel.SINGLE_SELECTION} -
    1918      *   Only one list index can be selected at a time. In this mode,
    1919      *   {@code setSelectionInterval} and {@code addSelectionInterval} are
    1920      *   equivalent, both replacing the current selection with the index
    1921      *   represented by the second argument (the "lead").
    1922      * <li>{@code ListSelectionModel.SINGLE_INTERVAL_SELECTION} -
    1923      *   Only one contiguous interval can be selected at a time.
    1924      *   In this mode, {@code addSelectionInterval} behaves like
    1925      *   {@code setSelectionInterval} (replacing the current selection},
    1926      *   unless the given interval is immediately adjacent to or overlaps
    1927      *   the existing selection, and can be used to grow the selection.
    1928      * <li>{@code ListSelectionModel.MULTIPLE_INTERVAL_SELECTION} -
    1929      *   In this mode, there's no restriction on what can be selected.
    1930      *   This mode is the default.
    1931      * </ul>
    1932      *
    1933      * @param selectionMode the selection mode
    1934      * @see #getSelectionMode
    1935      * @throws IllegalArgumentException if the selection mode isn't
    1936      *         one of those allowed
    1937      */
    1938     @BeanProperty(bound = false, enumerationValues = {
    1939             "ListSelectionModel.SINGLE_SELECTION",
    1940             "ListSelectionModel.SINGLE_INTERVAL_SELECTION",
    1941             "ListSelectionModel.MULTIPLE_INTERVAL_SELECTION"}, description
    1942             = "The selection mode.")
    1943     public void setSelectionMode(int selectionMode) {
    1944         getSelectionModel().setSelectionMode(selectionMode);
    1945     }
    1946
    1947     /**
    1948      * Returns the current selection mode for the list. This is a cover
    1949      * method that delegates to the method of the same name on the
    1950      * list's selection model.
    1951      *
    1952      * @return the current selection mode
    1953      * @see #setSelectionMode
    1954      */
    1955     public int getSelectionMode() {
    1956         return getSelectionModel().getSelectionMode();
    1957     }
    1958
    1959
    1960     /**
    1961      * Returns the anchor selection index. This is a cover method that
    1962      * delegates to the method of the same name on the list's selection model.
    1963      *
    1964      * @return the anchor selection index
    1965      * @see ListSelectionModel#getAnchorSelectionIndex
    1966      */
    1967     @BeanProperty(bound = false)
    1968     public int getAnchorSelectionIndex() {
    1969         return getSelectionModel().getAnchorSelectionIndex();
    1970     }
    1971
    1972
    1973     /**
    1974      * Returns the lead selection index. This is a cover method that
    1975      * delegates to the method of the same name on the list's selection model.
    1976      *
    1977      * @return the lead selection index
    1978      * @see ListSelectionModel#getLeadSelectionIndex
    1979      */
    1980     @BeanProperty(bound = false, description
    1981             = "The lead selection index.")
    1982     public int getLeadSelectionIndex() {
    1983         return getSelectionModel().getLeadSelectionIndex();
    1984     }
    1985
    1986
    1987     /**
    1988      * Returns the smallest selected cell index, or {@code -1} if the selection
    1989      * is empty. This is a cover method that delegates to the method of the same
    1990      * name on the list's selection model.
    1991      *
    1992      * @return the smallest selected cell index, or {@code -1}
    1993      * @see ListSelectionModel#getMinSelectionIndex
    1994      */
    1995     @BeanProperty(bound = false)
    1996     public int getMinSelectionIndex() {
    1997         return getSelectionModel().getMinSelectionIndex();
    1998     }
    1999
    2000
    2001     /**
    2002      * Returns the largest selected cell index, or {@code -1} if the selection
    2003      * is empty. This is a cover method that delegates to the method of the same
    2004      * name on the list's selection model.
    2005      *
    2006      * @return the largest selected cell index
    2007      * @see ListSelectionModel#getMaxSelectionIndex
    2008      */
    2009     @BeanProperty(bound = false)
    2010     public int getMaxSelectionIndex() {
    2011         return getSelectionModel().getMaxSelectionIndex();
    2012     }
    2013
    2014
    2015     /**
    2016      * Returns {@code true} if the specified index is selected,
    2017      * else {@code false}. This is a cover method that delegates to the method
    2018      * of the same name on the list's selection model.
    2019      *
    2020      * @param index index to be queried for selection state
    2021      * @return {@code true} if the specified index is selected,
    2022      *         else {@code false}
    2023      * @see ListSelectionModel#isSelectedIndex
    2024      * @see #setSelectedIndex
    2025      */
    2026     public boolean isSelectedIndex(int index) {
    2027         return getSelectionModel().isSelectedIndex(index);
    2028     }
    2029
    2030
    2031     /**
    2032      * Returns {@code true} if nothing is selected, else {@code false}.
    2033      * This is a cover method that delegates to the method of the same
    2034      * name on the list's selection model.
    2035      *
    2036      * @return {@code true} if nothing is selected, else {@code false}
    2037      * @see ListSelectionModel#isSelectionEmpty
    2038      * @see #clearSelection
    2039      */
    2040     @BeanProperty(bound = false)
    2041     public boolean isSelectionEmpty() {
    2042         return getSelectionModel().isSelectionEmpty();
    2043     }
    2044
    2045
    2046     /**
    2047      * Clears the selection; after calling this method, {@code isSelectionEmpty}
    2048      * will return {@code true}. This is a cover method that delegates to the
    2049      * method of the same name on the list's selection model.
    2050      *
    2051      * @see ListSelectionModel#clearSelection
    2052      * @see #isSelectionEmpty
    2053      */
    2054     public void clearSelection() {
    2055         getSelectionModel().clearSelection();
    2056     }
    2057
    2058
    2059     /**
    2060      * Selects the specified interval. Both {@code anchor} and {@code lead}
    2061      * indices are included. {@code anchor} doesn't have to be less than or
    2062      * equal to {@code lead}. This is a cover method that delegates to the
    2063      * method of the same name on the list's selection model.
    2064      * <p>
    2065      * Refer to the documentation of the selection model class being used
    2066      * for details on how values less than {@code 0} are handled.
    2067      *
    2068      * @param anchor the first index to select
    2069      * @param lead the last index to select
    2070      * @see ListSelectionModel#setSelectionInterval
    2071      * @see DefaultListSelectionModel#setSelectionInterval
    2072      * @see #createSelectionModel
    2073      * @see #addSelectionInterval
    2074      * @see #removeSelectionInterval
    2075      */
    2076     public void setSelectionInterval(int anchor, int lead) {
    2077         getSelectionModel().setSelectionInterval(anchor, lead);
    2078     }
    2079
    2080
    2081     /**
    2082      * Sets the selection to be the union of the specified interval with current
    2083      * selection. Both the {@code anchor} and {@code lead} indices are
    2084      * included. {@code anchor} doesn't have to be less than or
    2085      * equal to {@code lead}. This is a cover method that delegates to the
    2086      * method of the same name on the list's selection model.
    2087      * <p>
    2088      * Refer to the documentation of the selection model class being used
    2089      * for details on how values less than {@code 0} are handled.
    2090      *
    2091      * @param anchor the first index to add to the selection
    2092      * @param lead the last index to add to the selection
    2093      * @see ListSelectionModel#addSelectionInterval
    2094      * @see DefaultListSelectionModel#addSelectionInterval
    2095      * @see #createSelectionModel
    2096      * @see #setSelectionInterval
    2097      * @see #removeSelectionInterval
    2098      */
    2099     public void addSelectionInterval(int anchor, int lead) {
    2100         getSelectionModel().addSelectionInterval(anchor, lead);
    2101     }
    2102
    2103
    2104     /**
    2105      * Sets the selection to be the set difference of the specified interval
    2106      * and the current selection. Both the {@code index0} and {@code index1}
    2107      * indices are removed. {@code index0} doesn't have to be less than or
    2108      * equal to {@code index1}. This is a cover method that delegates to the
    2109      * method of the same name on the list's selection model.
    2110      * <p>
    2111      * Refer to the documentation of the selection model class being used
    2112      * for details on how values less than {@code 0} are handled.
    2113      *
    2114      * @param index0 the first index to remove from the selection
    2115      * @param index1 the last index to remove from the selection
    2116      * @see ListSelectionModel#removeSelectionInterval
    2117      * @see DefaultListSelectionModel#removeSelectionInterval
    2118      * @see #createSelectionModel
    2119      * @see #setSelectionInterval
    2120      * @see #addSelectionInterval
    2121      */
    2122     public void removeSelectionInterval(int index0, int index1) {
    2123         getSelectionModel().removeSelectionInterval(index0, index1);
    2124     }
    2125
    2126
    2127     /**
    2128      * Sets the selection model's {@code valueIsAdjusting} property. When
    2129      * {@code true}, upcoming changes to selection should be considered part
    2130      * of a single change. This property is used internally and developers
    2131      * typically need not call this method. For example, when the model is being
    2132      * updated in response to a user drag, the value of the property is set
    2133      * to {@code true} when the drag is initiated and set to {@code false}
    2134      * when the drag is finished. This allows listeners to update only
    2135      * when a change has been finalized, rather than handling all of the
    2136      * intermediate values.
    2137      * <p>
    2138      * You may want to use this directly if making a series of changes
    2139      * that should be considered part of a single change.
    2140      * <p>
    2141      * This is a cover method that delegates to the method of the same name on
    2142      * the list's selection model. See the documentation for
    2143      * {@link javax.swing.ListSelectionModel#setValueIsAdjusting} for
    2144      * more details.
    2145      *
    2146      * @param b the new value for the property
    2147      * @see ListSelectionModel#setValueIsAdjusting
    2148      * @see javax.swing.event.ListSelectionEvent#getValueIsAdjusting
    2149      * @see #getValueIsAdjusting
    2150      */
    2151     public void setValueIsAdjusting(boolean b) {
    2152         getSelectionModel().setValueIsAdjusting(b);
    2153     }
    2154
    2155
    2156     /**
    2157      * Returns the value of the selection model's {@code isAdjusting} property.
    2158      * <p>
    2159      * This is a cover method that delegates to the method of the same name on
    2160      * the list's selection model.
    2161      *
    2162      * @return the value of the selection model's {@code isAdjusting} property.
    2163      *
    2164      * @see #setValueIsAdjusting
    2165      * @see ListSelectionModel#getValueIsAdjusting
    2166      */
    2167     public boolean getValueIsAdjusting() {
    2168         return getSelectionModel().getValueIsAdjusting();
    2169     }
    2170
    2171
    2172     /**
    2173      * Returns an array of all of the selected indices, in increasing
    2174      * order.
    2175      *
    2176      * @return all of the selected indices, in increasing order,
    2177      *         or an empty array if nothing is selected
    2178      * @see #removeSelectionInterval
    2179      * @see #addListSelectionListener
    2180      */
    2181     @Transient
    2182     public int[] getSelectedIndices() {
    2183         return getSelectionModel().getSelectedIndices();

    2184     }
    2185
    2186
    2187     /**
    2188      * Selects a single cell. Does nothing if the given index is greater
    2189      * than or equal to the model size. This is a convenience method that uses
    2190      * {@code setSelectionInterval} on the selection model. Refer to the
    2191      * documentation for the selection model class being used for details on
    2192      * how values less than {@code 0} are handled.
    2193      *
    2194      * @param index the index of the cell to select
    2195      * @see ListSelectionModel#setSelectionInterval
    2196      * @see #isSelectedIndex
    2197      * @see #addListSelectionListener
    2198      */
    2199     @BeanProperty(bound = false, description
    2200             = "The index of the selected cell.")
    2201     public void setSelectedIndex(int index) {
    2202         if (index >= getModel().getSize()) {
    2203             return;
    2204         }
    2205         getSelectionModel().setSelectionInterval(index, index);
    2206     }
    2207
    2208
    2209     /**
    2210      * Changes the selection to be the set of indices specified by the given
    2211      * array. Indices greater than or equal to the model size are ignored.
    2212      * This is a convenience method that clears the selection and then uses
    2213      * {@code addSelectionInterval} on the selection model to add the indices.
    2214      * Refer to the documentation of the selection model class being used for
    2215      * details on how values less than {@code 0} are handled.
    2216      *
    2217      * @param indices an array of the indices of the cells to select,
    2218      *                {@code non-null}
    2219      * @see ListSelectionModel#addSelectionInterval
    2220      * @see #isSelectedIndex
    2221      * @see #addListSelectionListener
    2222      * @throws NullPointerException if the given array is {@code null}
    2223      */
    2224     public void setSelectedIndices(int[] indices) {
    2225         ListSelectionModel sm = getSelectionModel();
    2226         sm.clearSelection();
    2227         int size = getModel().getSize();
    2228         for (int i : indices) {
    2229             if (i < size) {
    2230                 sm.addSelectionInterval(i, i);
    2231             }
    2232         }
    2233     }
    2234
    2235
    2236     /**
    2237      * Returns an array of all the selected values, in increasing order based
    2238      * on their indices in the list.
    2239      *
    2240      * @return the selected values, or an empty array if nothing is selected
    2241      * @see #isSelectedIndex
    2242      * @see #getModel
    2243      * @see #addListSelectionListener
    2244      *
    2245      * @deprecated As of JDK 1.7, replaced by {@link #getSelectedValuesList()}
    2246      */
    2247     @Deprecated
    2248     @BeanProperty(bound = false)
    2249     public Object[] getSelectedValues() {

    2250         ListModel<E> dm = getModel();
    2251         int[] selectedIndices = getSelectedIndices();
    2252         int length = selectedIndices.length;
    2253
    2254         if (length > 0) {
    2255             Object[] rv = new Object[length];
    2256             for (int i = 0; i < length; i++) {
    2257                     rv[i] = dm.getElementAt(selectedIndices[i]);

    2258             }

    2259             return rv;
    2260         }
    2261         return new Object[0];
    2262     }
    2263
    2264     /**
    2265      * Returns a list of all the selected items, in increasing order based
    2266      * on their indices in the list.
    2267      *
    2268      * @return the selected items, or an empty list if nothing is selected
    2269      * @see #isSelectedIndex
    2270      * @see #getModel
    2271      * @see #addListSelectionListener
    2272      *
    2273      * @since 1.7
    2274      */
    2275     @BeanProperty(bound = false)
    2276     public List<E> getSelectedValuesList() {

    2277         ListModel<E> dm = getModel();
    2278         int[] selectedIndices = getSelectedIndices();
    2279
    2280         if (selectedIndices.length > 0) {

    2281             List<E> selectedItems = new ArrayList<E>();
    2282             for (int i : selectedIndices) {

    2283                     selectedItems.add(dm.getElementAt(i));
    2284             }

    2285             return selectedItems;
    2286         }
    2287         return Collections.emptyList();
    2288     }
    2289
    2290
    2291     /**
    2292      * Returns the smallest selected cell index; <i>the selection</i> when only
    2293      * a single item is selected in the list. When multiple items are selected,
    2294      * it is simply the smallest selected index. Returns {@code -1} if there is
    2295      * no selection.
    2296      * <p>
    2297      * This method is a cover that delegates to {@code getMinSelectionIndex}.
    2298      *
    2299      * @return the smallest selected cell index
    2300      * @see #getMinSelectionIndex
    2301      * @see #addListSelectionListener
    2302      */
    2303     public int getSelectedIndex() {
    2304         return getMinSelectionIndex();
    2305     }
    2306
    2307
    2308     /**
    2309      * Returns the value for the smallest selected cell index;
    2310      * <i>the selected value</i> when only a single item is selected in the
    2311      * list. When multiple items are selected, it is simply the value for the
    2312      * smallest selected index. Returns {@code null} if there is no selection.
    2313      * <p>
    2314      * This is a convenience method that simply returns the model value for
    2315      * {@code getMinSelectionIndex}.
    2316      *
    2317      * @return the first selected value
    2318      * @see #getMinSelectionIndex
    2319      * @see #getModel
    2320      * @see #addListSelectionListener
    2321      */
    2322     @BeanProperty(bound = false)
    2323     public E getSelectedValue() {
    2324         int i = getMinSelectionIndex();
    2325         return (i == -1) ? null : getModel().getElementAt(i);
    2326     }
    2327
    2328
    2329     /**
    2330      * Selects the specified object from the list.
    2331      *
    2332      * @param anObject      the object to select
    2333      * @param shouldScroll  {@code true} if the list should scroll to display
    2334      *                      the selected object, if one exists; otherwise {@code false}
    2335      */
    2336     public void setSelectedValue(Object anObject,boolean shouldScroll) {
    2337         if(anObject == null)
    2338             setSelectedIndex(-1);
    2339         else if(!anObject.equals(getSelectedValue())) {
    2340             int i,c;
    2341             ListModel<E> dm = getModel();
    2342             for(i=0,c=dm.getSize();i<c;i++)
    2343                 if(anObject.equals(dm.getElementAt(i))){
    2344                     setSelectedIndex(i);
    2345                     if(shouldScroll)
    2346                         ensureIndexIsVisible(i);
    2347                     repaint();  /** FIX-ME setSelectedIndex does not redraw all the time with the basic l&f**/
    2348                     return;
    2349                 }
    2350             setSelectedIndex(-1);
    2351         }
    2352         repaint(); /** FIX-ME setSelectedIndex does not redraw all the time with the basic l&f**/
    2353     }
    2354
    2355
    2356
    2357     /**
    2358      * --- The Scrollable Implementation ---
    2359      */
    2360
    2361     private void checkScrollableParameters(Rectangle visibleRect, int orientation) {
    2362         if (visibleRect == null) {
    2363             throw new IllegalArgumentException("visibleRect must be non-null");
    2364         }
    2365         switch (orientation) {
    2366         case SwingConstants.VERTICAL:
    2367         case SwingConstants.HORIZONTAL:
    2368             break;
    2369         default:
    2370             throw new IllegalArgumentException("orientation must be one of: VERTICAL, HORIZONTAL");
    2371         }
    2372     }
    2373
    2374
    2375     /**
    2376      * Computes the size of viewport needed to display {@code visibleRowCount}
    2377      * rows. The value returned by this method depends on the layout
    2378      * orientation:
    2379      * <p>
    2380      * <b>{@code VERTICAL}:</b>
    2381      * <br>
    2382      * This is trivial if both {@code fixedCellWidth} and {@code fixedCellHeight}
    2383      * have been set (either explicitly or by specifying a prototype cell value).
    2384      * The width is simply the {@code fixedCellWidth} plus the list's horizontal
    2385      * insets. The height is the {@code fixedCellHeight} multiplied by the
    2386      * {@code visibleRowCount}, plus the list's vertical insets.
    2387      * <p>
    2388      * If either {@code fixedCellWidth} or {@code fixedCellHeight} haven't been
    2389      * specified, heuristics are used. If the model is empty, the width is
    2390      * the {@code fixedCellWidth}, if greater than {@code 0}, or a hard-coded
    2391      * value of {@code 256}. The height is the {@code fixedCellHeight} multiplied
    2392      * by {@code visibleRowCount}, if {@code fixedCellHeight} is greater than
    2393      * {@code 0}, otherwise it is a hard-coded value of {@code 16} multiplied by
    2394      * {@code visibleRowCount}.
    2395      * <p>
    2396      * If the model isn't empty, the width is the preferred size's width,
    2397      * typically the width of the widest list element. The height is the
    2398      * {@code fixedCellHeight} multiplied by the {@code visibleRowCount},
    2399      * plus the list's vertical insets.
    2400      * <p>
    2401      * <b>{@code VERTICAL_WRAP} or {@code HORIZONTAL_WRAP}:</b>
    2402      * <br>
    2403      * This method simply returns the value from {@code getPreferredSize}.
    2404      * The list's {@code ListUI} is expected to override {@code getPreferredSize}
    2405      * to return an appropriate value.
    2406      *
    2407      * @return a dimension containing the size of the viewport needed
    2408      *          to display {@code visibleRowCount} rows
    2409      * @see #getPreferredScrollableViewportSize
    2410      * @see #setPrototypeCellValue
    2411      */
    2412     @BeanProperty(bound = false)
    2413     public Dimension getPreferredScrollableViewportSize()
    2414     {
    2415         if (getLayoutOrientation() != VERTICAL) {
    2416             return getPreferredSize();
    2417         }
    2418         Insets insets = getInsets();
    2419         int dx = insets.left + insets.right;
    2420         int dy = insets.top + insets.bottom;
    2421
    2422         int visibleRowCount = getVisibleRowCount();
    2423         int fixedCellWidth = getFixedCellWidth();
    2424         int fixedCellHeight = getFixedCellHeight();
    2425
    2426         if ((fixedCellWidth > 0) && (fixedCellHeight > 0)) {
    2427             int width = fixedCellWidth + dx;
    2428             int height = (visibleRowCount * fixedCellHeight) + dy;
    2429             return new Dimension(width, height);
    2430         }
    2431         else if (getModel().getSize() > 0) {
    2432             int width = getPreferredSize().width;
    2433             int height;
    2434             Rectangle r = getCellBounds(0, 0);
    2435             if (r != null) {
    2436                 height = (visibleRowCount * r.height) + dy;
    2437             }
    2438             else {
    2439                 // Will only happen if UI null, shouldn't matter what we return
    2440                 height = 1;
    2441             }
    2442             return new Dimension(width, height);
    2443         }
    2444         else {
    2445             fixedCellWidth = (fixedCellWidth > 0) ? fixedCellWidth : 256;
    2446             fixedCellHeight = (fixedCellHeight > 0) ? fixedCellHeight : 16;
    2447             return new Dimension(fixedCellWidth, fixedCellHeight * visibleRowCount);
    2448         }
    2449     }
    2450
    2451
    2452     /**
    2453      * Returns the distance to scroll to expose the next or previous
    2454      * row (for vertical scrolling) or column (for horizontal scrolling).
    2455      * <p>
    2456      * For horizontal scrolling, if the layout orientation is {@code VERTICAL},
    2457      * then the list's font size is returned (or {@code 1} if the font is
    2458      * {@code null}).
    2459      *
    2460      * @param visibleRect the view area visible within the viewport
    2461      * @param orientation {@code SwingConstants.HORIZONTAL} or
    2462      *                    {@code SwingConstants.VERTICAL}
    2463      * @param direction less or equal to zero to scroll up/back,
    2464      *                  greater than zero for down/forward
    2465      * @return the "unit" increment for scrolling in the specified direction;
    2466      *         always positive
    2467      * @see #getScrollableBlockIncrement
    2468      * @see Scrollable#getScrollableUnitIncrement
    2469      * @throws IllegalArgumentException if {@code visibleRect} is {@code null}, or
    2470      *         {@code orientation} isn't one of {@code SwingConstants.VERTICAL} or
    2471      *         {@code SwingConstants.HORIZONTAL}
    2472      */
    2473     public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction)
    2474     {
    2475         checkScrollableParameters(visibleRect, orientation);
    2476
    2477         if (orientation == SwingConstants.VERTICAL) {
    2478             int row = locationToIndex(visibleRect.getLocation());
    2479
    2480             if (row == -1) {
    2481                 return 0;
    2482             }
    2483             else {
    2484                 /* Scroll Down */
    2485                 if (direction > 0) {
    2486                     Rectangle r = getCellBounds(row, row);
    2487                     return (r == null) ? 0 : r.height - (visibleRect.y - r.y);
    2488                 }
    2489                 /* Scroll Up */
    2490                 else {
    2491                     Rectangle r = getCellBounds(row, row);
    2492
    2493                     /* The first row is completely visible and it's row 0.
    2494                      * We're done.
    2495                      */
    2496                     if ((r.y == visibleRect.y) && (row == 0))  {
    2497                         return 0;
    2498                     }
    2499                     /* The first row is completely visible, return the
    2500                      * height of the previous row or 0 if the first row
    2501                      * is the top row of the list.
    2502                      */
    2503                     else if (r.y == visibleRect.y) {
    2504                         Point loc = r.getLocation();
    2505                         loc.y--;
    2506                         int prevIndex = locationToIndex(loc);
    2507                         Rectangle prevR = getCellBounds(prevIndex, prevIndex);
    2508
    2509                         if (prevR == null || prevR.y >= r.y) {
    2510                             return 0;
    2511                         }
    2512                         return prevR.height;
    2513                     }
    2514                     /* The first row is partially visible, return the
    2515                      * height of hidden part.
    2516                      */
    2517                     else {
    2518                         return visibleRect.y - r.y;
    2519                     }
    2520                 }
    2521             }
    2522         } else if (orientation == SwingConstants.HORIZONTAL &&
    2523                            getLayoutOrientation() != JList.VERTICAL) {
    2524             boolean leftToRight = getComponentOrientation().isLeftToRight();
    2525             int index;
    2526             Point leadingPoint;
    2527
    2528             if (leftToRight) {
    2529                 leadingPoint = visibleRect.getLocation();
    2530             }
    2531             else {
    2532                 leadingPoint = new Point(visibleRect.x + visibleRect.width -1,
    2533                                          visibleRect.y);
    2534             }
    2535             index = locationToIndex(leadingPoint);
    2536
    2537             if (index != -1) {
    2538                 Rectangle cellBounds = getCellBounds(index, index);
    2539                 if (cellBounds != null && cellBounds.contains(leadingPoint)) {
    2540                     int leadingVisibleEdge;
    2541                     int leadingCellEdge;
    2542
    2543                     if (leftToRight) {
    2544                         leadingVisibleEdge = visibleRect.x;
    2545                         leadingCellEdge = cellBounds.x;
    2546                     }
    2547                     else {
    2548                         leadingVisibleEdge = visibleRect.x + visibleRect.width;
    2549                         leadingCellEdge = cellBounds.x + cellBounds.width;
    2550                     }
    2551
    2552                     if (leadingCellEdge != leadingVisibleEdge) {
    2553                         if (direction < 0) {
    2554                             // Show remainder of leading cell
    2555                             return Math.abs(leadingVisibleEdge - leadingCellEdge);
    2556
    2557                         }
    2558                         else if (leftToRight) {
    2559                             // Hide rest of leading cell
    2560                             return leadingCellEdge + cellBounds.width - leadingVisibleEdge;
    2561                         }
    2562                         else {
    2563                             // Hide rest of leading cell
    2564                             return leadingVisibleEdge - cellBounds.x;
    2565                         }
    2566                     }
    2567                     // ASSUME: All cells are the same width
    2568                     return cellBounds.width;
    2569                 }
    2570             }
    2571         }
    2572         Font f = getFont();
    2573         return (f != null) ? f.getSize() : 1;
    2574     }
    2575
    2576
    2577     /**
    2578      * Returns the distance to scroll to expose the next or previous block.
    2579      * <p>
    2580      * For vertical scrolling, the following rules are used:
    2581      * <ul>
    2582      * <li>if scrolling down, returns the distance to scroll so that the last
    2583      * visible element becomes the first completely visible element
    2584      * <li>if scrolling up, returns the distance to scroll so that the first
    2585      * visible element becomes the last completely visible element
    2586      * <li>returns {@code visibleRect.height} if the list is empty
    2587      * </ul>
    2588      * <p>
    2589      * For horizontal scrolling, when the layout orientation is either
    2590      * {@code VERTICAL_WRAP} or {@code HORIZONTAL_WRAP}:
    2591      * <ul>
    2592      * <li>if scrolling right, returns the distance to scroll so that the
    2593      * last visible element becomes
    2594      * the first completely visible element
    2595      * <li>if scrolling left, returns the distance to scroll so that the first
    2596      * visible element becomes the last completely visible element
    2597      * <li>returns {@code visibleRect.width} if the list is empty
    2598      * </ul>
    2599      * <p>
    2600      * For horizontal scrolling and {@code VERTICAL} orientation,
    2601      * returns {@code visibleRect.width}.
    2602      * <p>
    2603      * Note that the value of {@code visibleRect} must be the equal to
    2604      * {@code this.getVisibleRect()}.
    2605      *
    2606      * @param visibleRect the view area visible within the viewport
    2607      * @param orientation {@code SwingConstants.HORIZONTAL} or
    2608      *                    {@code SwingConstants.VERTICAL}
    2609      * @param direction less or equal to zero to scroll up/back,
    2610      *                  greater than zero for down/forward
    2611      * @return the "block" increment for scrolling in the specified direction;
    2612      *         always positive
    2613      * @see #getScrollableUnitIncrement
    2614      * @see Scrollable#getScrollableBlockIncrement
    2615      * @throws IllegalArgumentException if {@code visibleRect} is {@code null}, or
    2616      *         {@code orientation} isn't one of {@code SwingConstants.VERTICAL} or
    2617      *         {@code SwingConstants.HORIZONTAL}
    2618      */
    2619     public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
    2620         checkScrollableParameters(visibleRect, orientation);
    2621         if (orientation == SwingConstants.VERTICAL) {
    2622             int inc = visibleRect.height;
    2623             /* Scroll Down */
    2624             if (direction > 0) {
    2625                 // last cell is the lowest left cell
    2626                 int last = locationToIndex(new Point(visibleRect.x, visibleRect.y+visibleRect.height-1));
    2627                 if (last != -1) {
    2628                     Rectangle lastRect = getCellBounds(last,last);
    2629                     if (lastRect != null) {
    2630                         inc = lastRect.y - visibleRect.y;
    2631                         if ( (inc == 0) && (last < getModel().getSize()-1) ) {
    2632                             inc = lastRect.height;
    2633                         }
    2634                     }
    2635                 }
    2636             }
    2637             /* Scroll Up */
    2638             else {
    2639                 int newFirst = locationToIndex(new Point(visibleRect.x, visibleRect.y-visibleRect.height));
    2640                 int first = getFirstVisibleIndex();
    2641                 if (newFirst != -1) {
    2642                     if (first == -1) {
    2643                         first = locationToIndex(visibleRect.getLocation());
    2644                     }
    2645                     Rectangle newFirstRect = getCellBounds(newFirst,newFirst);
    2646                     Rectangle firstRect = getCellBounds(first,first);
    2647                     if ((newFirstRect != null) && (firstRect!=null)) {
    2648                         while ( (newFirstRect.y + visibleRect.height <
    2649                                  firstRect.y + firstRect.height) &&
    2650                                 (newFirstRect.y < firstRect.y) ) {
    2651                             newFirst++;
    2652                             newFirstRect = getCellBounds(newFirst,newFirst);
    2653                         }
    2654                         inc = visibleRect.y - newFirstRect.y;
    2655                         if ( (inc <= 0) && (newFirstRect.y > 0)) {
    2656                             newFirst--;
    2657                             newFirstRect = getCellBounds(newFirst,newFirst);
    2658                             if (newFirstRect != null) {
    2659                                 inc = visibleRect.y - newFirstRect.y;
    2660                             }
    2661                         }
    2662                     }
    2663                 }
    2664             }
    2665             return inc;
    2666         }
    2667         else if (orientation == SwingConstants.HORIZONTAL &&
    2668                  getLayoutOrientation() != JList.VERTICAL) {
    2669             boolean leftToRight = getComponentOrientation().isLeftToRight();
    2670             int inc = visibleRect.width;
    2671             /* Scroll Right (in ltr mode) or Scroll Left (in rtl mode) */
    2672             if (direction > 0) {
    2673                 // position is upper right if ltr, or upper left otherwise
    2674                 int x = visibleRect.x + (leftToRight ? (visibleRect.width - 1) : 0);
    2675                 int last = locationToIndex(new Point(x, visibleRect.y));
    2676
    2677                 if (last != -1) {
    2678                     Rectangle lastRect = getCellBounds(last,last);
    2679                     if (lastRect != null) {
    2680                         if (leftToRight) {
    2681                             inc = lastRect.x - visibleRect.x;
    2682                         } else {
    2683                             inc = visibleRect.x + visibleRect.width
    2684                                       - (lastRect.x + lastRect.width);
    2685                         }
    2686                         if (inc < 0) {
    2687                             inc += lastRect.width;
    2688                         } else if ( (inc == 0) && (last < getModel().getSize()-1) ) {
    2689                             inc = lastRect.width;
    2690                         }
    2691                     }
    2692                 }
    2693             }
    2694             /* Scroll Left (in ltr mode) or Scroll Right (in rtl mode) */
    2695             else {
    2696                 // position is upper left corner of the visibleRect shifted
    2697                 // left by the visibleRect.width if ltr, or upper right shifted
    2698                 // right by the visibleRect.width otherwise
    2699                 int x = visibleRect.x + (leftToRight
    2700                                          ? -visibleRect.width
    2701                                          : visibleRect.width - 1 + visibleRect.width);
    2702                 int first = locationToIndex(new Point(x, visibleRect.y));
    2703
    2704                 if (first != -1) {
    2705                     Rectangle firstRect = getCellBounds(first,first);
    2706                     if (firstRect != null) {
    2707                         // the right of the first cell
    2708                         int firstRight = firstRect.x + firstRect.width;
    2709
    2710                         if (leftToRight) {
    2711                             if ((firstRect.x < visibleRect.x - visibleRect.width)
    2712                                     && (firstRight < visibleRect.x)) {
    2713                                 inc = visibleRect.x - firstRight;
    2714                             } else {
    2715                                 inc = visibleRect.x - firstRect.x;
    2716                             }
    2717                         } else {
    2718                             int visibleRight = visibleRect.x + visibleRect.width;
    2719
    2720                             if ((firstRight > visibleRight + visibleRect.width)
    2721                                     && (firstRect.x > visibleRight)) {
    2722                                 inc = firstRect.x - visibleRight;
    2723                             } else {
    2724                                 inc = firstRight - visibleRight;
    2725                             }
    2726                         }
    2727                     }
    2728                 }
    2729             }
    2730             return inc;
    2731         }
    2732         return visibleRect.width;
    2733     }
    2734
    2735
    2736     /**
    2737      * Returns {@code true} if this {@code JList} is displayed in a
    2738      * {@code JViewport} and the viewport is wider than the list's
    2739      * preferred width, or if the layout orientation is {@code HORIZONTAL_WRAP}
    2740      * and {@code visibleRowCount <= 0}; otherwise returns {@code false}.
    2741      * <p>
    2742      * If {@code false}, then don't track the viewport's width. This allows
    2743      * horizontal scrolling if the {@code JViewport} is itself embedded in a
    2744      * {@code JScrollPane}.
    2745      *
    2746      * @return whether or not an enclosing viewport should force the list's
    2747      *         width to match its own
    2748      * @see Scrollable#getScrollableTracksViewportWidth
    2749      */
    2750     @BeanProperty(bound = false)
    2751     public boolean getScrollableTracksViewportWidth() {
    2752         if (getLayoutOrientation() == HORIZONTAL_WRAP &&
    2753                                       getVisibleRowCount() <= 0) {
    2754             return true;
    2755         }
    2756         Container parent = SwingUtilities.getUnwrappedParent(this);
    2757         if (parent instanceof JViewport) {
    2758             return parent.getWidth() > getPreferredSize().width;
    2759         }
    2760         return false;
    2761     }
    2762
    2763     /**
    2764      * Returns {@code true} if this {@code JList} is displayed in a
    2765      * {@code JViewport} and the viewport is taller than the list's
    2766      * preferred height, or if the layout orientation is {@code VERTICAL_WRAP}
    2767      * and {@code visibleRowCount <= 0}; otherwise returns {@code false}.
    2768      * <p>
    2769      * If {@code false}, then don't track the viewport's height. This allows
    2770      * vertical scrolling if the {@code JViewport} is itself embedded in a
    2771      * {@code JScrollPane}.
    2772      *
    2773      * @return whether or not an enclosing viewport should force the list's
    2774      *         height to match its own
    2775      * @see Scrollable#getScrollableTracksViewportHeight
    2776      */
    2777     @BeanProperty(bound = false)
    2778     public boolean getScrollableTracksViewportHeight() {
    2779         if (getLayoutOrientation() == VERTICAL_WRAP &&
    2780                      getVisibleRowCount() <= 0) {
    2781             return true;
    2782         }
    2783         Container parent = SwingUtilities.getUnwrappedParent(this);
    2784         if (parent instanceof JViewport) {
    2785             return parent.getHeight() > getPreferredSize().height;
    2786         }
    2787         return false;
    2788     }
    2789
    2790
    2791     /*
    2792      * See {@code readObject} and {@code writeObject} in {@code JComponent}
    2793      * for more information about serialization in Swing.
    2794      */
    2795     private void writeObject(ObjectOutputStream s) throws IOException {
    2796         s.defaultWriteObject();
    2797         if (getUIClassID().equals(uiClassID)) {
    2798             byte count = JComponent.getWriteObjCounter(this);
    2799             JComponent.setWriteObjCounter(this, --count);
    2800             if (count == 0 && ui != null) {
    2801                 ui.installUI(this);
    2802             }
    2803         }
    2804     }
    2805
    2806
    2807     /**
    2808      * Returns a {@code String} representation of this {@code JList}.
    2809      * This method is intended to be used only for debugging purposes,
    2810      * and the content and format of the returned {@code String} may vary
    2811      * between implementations. The returned {@code String} may be empty,
    2812      * but may not be {@code null}.
    2813      *
    2814      * @return  a {@code String} representation of this {@code JList}.
    2815      */
    2816     protected String paramString() {
    2817         String selectionForegroundString = (selectionForeground != null ?
    2818                                             selectionForeground.toString() :
    2819                                             "");
    2820         String selectionBackgroundString = (selectionBackground != null ?
    2821                                             selectionBackground.toString() :
    2822                                             "");
    2823
    2824         return super.paramString() +
    2825         ",fixedCellHeight=" + fixedCellHeight +
    2826         ",fixedCellWidth=" + fixedCellWidth +
    2827         ",horizontalScrollIncrement=" + horizontalScrollIncrement +
    2828         ",selectionBackground=" + selectionBackgroundString +
    2829         ",selectionForeground=" + selectionForegroundString +
    2830         ",visibleRowCount=" + visibleRowCount +
    2831         ",layoutOrientation=" + layoutOrientation;
    2832     }
    2833
    2834
    2835     /**
    2836      * --- Accessibility Support ---
    2837      */
    2838
    2839     /**
    2840      * Gets the {@code AccessibleContext} associated with this {@code JList}.
    2841      * For {@code JList}, the {@code AccessibleContext} takes the form of an
    2842      * {@code AccessibleJList}.
    2843      * <p>
    2844      * A new {@code AccessibleJList} instance is created if necessary.
    2845      *
    2846      * @return an {@code AccessibleJList} that serves as the
    2847      *         {@code AccessibleContext} of this {@code JList}
    2848      */
    2849     @BeanProperty(bound = false)
    2850     public AccessibleContext getAccessibleContext() {
    2851         if (accessibleContext == null) {
    2852             accessibleContext = new AccessibleJList();
    2853         }
    2854         return accessibleContext;
    2855     }
    2856
    2857     /**
    2858      * This class implements accessibility support for the
    2859      * {@code JList} class. It provides an implementation of the
    2860      * Java Accessibility API appropriate to list user-interface
    2861      * elements.
    2862      * <p>
    2863      * <strong>Warning:</strong>
    2864      * Serialized objects of this class will not be compatible with
    2865      * future Swing releases. The current serialization support is
    2866      * appropriate for short term storage or RMI between applications running
    2867      * the same version of Swing.  As of 1.4, support for long term storage
    2868      * of all JavaBeans&trade;
    2869      * has been added to the <code>java.beans</code> package.
    2870      * Please see {@link java.beans.XMLEncoder}.
    2871      */
    2872     @SuppressWarnings("serial") // Same-version serialization only
    2873     protected class AccessibleJList extends AccessibleJComponent
    2874         implements AccessibleSelection, PropertyChangeListener,
    2875         ListSelectionListener, ListDataListener {
    2876
    2877         int leadSelectionIndex;
    2878
    2879         /**
    2880          * Constructs an {@code AccessibleJList}.
    2881          */
    2882         public AccessibleJList() {
    2883             super();
    2884             JList.this.addPropertyChangeListener(this);
    2885             JList.this.getSelectionModel().addListSelectionListener(this);
    2886             JList.this.getModel().addListDataListener(this);
    2887             leadSelectionIndex = JList.this.getLeadSelectionIndex();
    2888         }
    2889
    2890         /**
    2891          * Property Change Listener change method. Used to track changes
    2892          * to the DataModel and ListSelectionModel, in order to re-set
    2893          * listeners to those for reporting changes there via the Accessibility
    2894          * PropertyChange mechanism.
    2895          *
    2896          * @param e PropertyChangeEvent
    2897          */
    2898         public void propertyChange(PropertyChangeEvent e) {
    2899             String name = e.getPropertyName();
    2900             Object oldValue = e.getOldValue();
    2901             Object newValue = e.getNewValue();
    2902
    2903                 // re-set listData listeners
    2904             if (name.compareTo("model") == 0) {
    2905
    2906                 if (oldValue != null && oldValue instanceof ListModel) {
    2907                     ((ListModel) oldValue).removeListDataListener(this);
    2908                 }
    2909                 if (newValue != null && newValue instanceof ListModel) {
    2910                     ((ListModel) newValue).addListDataListener(this);
    2911                 }
    2912
    2913                 // re-set listSelectionModel listeners
    2914             } else if (name.compareTo("selectionModel") == 0) {
    2915
    2916                 if (oldValue != null && oldValue instanceof ListSelectionModel) {
    2917                     ((ListSelectionModel) oldValue).removeListSelectionListener(this);
    2918                 }
    2919                 if (newValue != null && newValue instanceof ListSelectionModel) {
    2920                     ((ListSelectionModel) newValue).addListSelectionListener(this);
    2921                 }
    2922
    2923                 firePropertyChange(
    2924                     AccessibleContext.ACCESSIBLE_SELECTION_PROPERTY,
    2925                     Boolean.valueOf(false), Boolean.valueOf(true));
    2926             }
    2927         }
    2928
    2929         /**
    2930          * List Selection Listener value change method. Used to fire
    2931          * the property change
    2932          *
    2933          * @param e ListSelectionEvent
    2934          *
    2935          */
    2936         public void valueChanged(ListSelectionEvent e) {
    2937             int oldLeadSelectionIndex = leadSelectionIndex;
    2938             leadSelectionIndex = JList.this.getLeadSelectionIndex();
    2939             if (oldLeadSelectionIndex != leadSelectionIndex) {
    2940                 Accessible oldLS, newLS;
    2941                 oldLS = (oldLeadSelectionIndex >= 0)
    2942                         ? getAccessibleChild(oldLeadSelectionIndex)
    2943                         : null;
    2944                 newLS = (leadSelectionIndex >= 0)
    2945                         ? getAccessibleChild(leadSelectionIndex)
    2946                         : null;
    2947                 firePropertyChange(AccessibleContext.ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY,
    2948                                    oldLS, newLS);
    2949             }
    2950
    2951             firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
    2952                                Boolean.valueOf(false), Boolean.valueOf(true));
    2953             firePropertyChange(AccessibleContext.ACCESSIBLE_SELECTION_PROPERTY,
    2954                                Boolean.valueOf(false), Boolean.valueOf(true));
    2955
    2956             // Process the State changes for Multiselectable
    2957             AccessibleStateSet s = getAccessibleStateSet();
    2958             ListSelectionModel lsm = JList.this.getSelectionModel();
    2959             if (lsm.getSelectionMode() != ListSelectionModel.SINGLE_SELECTION) {
    2960                 if (!s.contains(AccessibleState.MULTISELECTABLE)) {
    2961                     s.add(AccessibleState.MULTISELECTABLE);
    2962                     firePropertyChange(AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
    2963                                        null, AccessibleState.MULTISELECTABLE);
    2964                 }
    2965             } else {
    2966                 if (s.contains(AccessibleState.MULTISELECTABLE)) {
    2967                     s.remove(AccessibleState.MULTISELECTABLE);
    2968                     firePropertyChange(AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
    2969                                        AccessibleState.MULTISELECTABLE, null);
    2970                 }
    2971             }
    2972         }
    2973
    2974         /**
    2975          * List Data Listener interval added method. Used to fire the visible data property change
    2976          *
    2977          * @param e ListDataEvent
    2978          *
    2979          */
    2980         public void intervalAdded(ListDataEvent e) {
    2981             firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
    2982                                Boolean.valueOf(false), Boolean.valueOf(true));
    2983         }
    2984
    2985         /**
    2986          * List Data Listener interval removed method. Used to fire the visible data property change
    2987          *
    2988          * @param e ListDataEvent
    2989          *
    2990          */
    2991         public void intervalRemoved(ListDataEvent e) {
    2992             firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
    2993                                Boolean.valueOf(false), Boolean.valueOf(true));
    2994         }
    2995
    2996         /**
    2997          * List Data Listener contents changed method. Used to fire the visible data property change
    2998          *
    2999          * @param e ListDataEvent
    3000          *
    3001          */
    3002          public void contentsChanged(ListDataEvent e) {
    3003              firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
    3004                                 Boolean.valueOf(false), Boolean.valueOf(true));
    3005          }
    3006
    3007     // AccessibleContext methods
    3008
    3009         /**
    3010          * Get the state set of this object.
    3011          *
    3012          * @return an instance of AccessibleState containing the current state
    3013          * of the object
    3014          * @see AccessibleState
    3015          */
    3016         public AccessibleStateSet getAccessibleStateSet() {
    3017             AccessibleStateSet states = super.getAccessibleStateSet();
    3018             if (selectionModel.getSelectionMode() !=
    3019                 ListSelectionModel.SINGLE_SELECTION) {
    3020                 states.add(AccessibleState.MULTISELECTABLE);
    3021             }
    3022             return states;
    3023         }
    3024
    3025         /**
    3026          * Get the role of this object.
    3027          *
    3028          * @return an instance of AccessibleRole describing the role of the
    3029          * object
    3030          * @see AccessibleRole
    3031          */
    3032         public AccessibleRole getAccessibleRole() {
    3033             return AccessibleRole.LIST;
    3034         }
    3035
    3036         /**
    3037          * Returns the <code>Accessible</code> child contained at
    3038          * the local coordinate <code>Point</code>, if one exists.
    3039          * Otherwise returns <code>null</code>.
    3040          *
    3041          * @return the <code>Accessible</code> at the specified
    3042          *    location, if it exists
    3043          */
    3044         public Accessible getAccessibleAt(Point p) {
    3045             int i = locationToIndex(p);
    3046             if (i >= 0) {
    3047                 return new AccessibleJListChild(JList.this, i);
    3048             } else {
    3049                 return null;
    3050             }
    3051         }
    3052
    3053         /**
    3054          * Returns the number of accessible children in the object.  If all
    3055          * of the children of this object implement Accessible, than this
    3056          * method should return the number of children of this object.
    3057          *
    3058          * @return the number of accessible children in the object.
    3059          */
    3060         public int getAccessibleChildrenCount() {
    3061             return getModel().getSize();
    3062         }
    3063
    3064         /**
    3065          * Return the nth Accessible child of the object.
    3066          *
    3067          * @param i zero-based index of child
    3068          * @return the nth Accessible child of the object
    3069          */
    3070         public Accessible getAccessibleChild(int i) {
    3071             if (i >= getModel().getSize()) {
    3072                 return null;
    3073             } else {
    3074                 return new AccessibleJListChild(JList.this, i);
    3075             }
    3076         }
    3077
    3078         /**
    3079          * Get the AccessibleSelection associated with this object.  In the
    3080          * implementation of the Java Accessibility API for this class,
    3081          * return this object, which is responsible for implementing the
    3082          * AccessibleSelection interface on behalf of itself.
    3083          *
    3084          * @return this object
    3085          */
    3086         public AccessibleSelection getAccessibleSelection() {
    3087             return this;
    3088         }
    3089
    3090
    3091     // AccessibleSelection methods
    3092
    3093         /**
    3094          * Returns the number of items currently selected.
    3095          * If no items are selected, the return value will be 0.
    3096          *
    3097          * @return the number of items currently selected.
    3098          */
    3099          public int getAccessibleSelectionCount() {
    3100              return JList.this.getSelectedIndices().length;
    3101          }
    3102
    3103         /**
    3104          * Returns an Accessible representing the specified selected item
    3105          * in the object.  If there isn't a selection, or there are
    3106          * fewer items selected than the integer passed in, the return
    3107          * value will be <code>null</code>.
    3108          *
    3109          * @param i the zero-based index of selected items
    3110          * @return an Accessible containing the selected item
    3111          */
    3112          public Accessible getAccessibleSelection(int i) {
    3113              int len = getAccessibleSelectionCount();
    3114              if (i < 0 || i >= len) {
    3115                  return null;
    3116              } else {
    3117                  return getAccessibleChild(JList.this.getSelectedIndices()[i]);
    3118              }
    3119          }
    3120
    3121         /**
    3122          * Returns true if the current child of this object is selected.
    3123          *
    3124          * @param i the zero-based index of the child in this Accessible
    3125          * object.
    3126          * @see AccessibleContext#getAccessibleChild
    3127          */
    3128         public boolean isAccessibleChildSelected(int i) {
    3129             return isSelectedIndex(i);
    3130         }
    3131
    3132         /**
    3133          * Adds the specified selected item in the object to the object's
    3134          * selection.  If the object supports multiple selections,
    3135          * the specified item is added to any existing selection, otherwise
    3136          * it replaces any existing selection in the object.  If the
    3137          * specified item is already selected, this method has no effect.
    3138          *
    3139          * @param i the zero-based index of selectable items
    3140          */
    3141          public void addAccessibleSelection(int i) {
    3142              JList.this.addSelectionInterval(i, i);
    3143          }
    3144
    3145         /**
    3146          * Removes the specified selected item in the object from the object's
    3147          * selection.  If the specified item isn't currently selected, this
    3148          * method has no effect.
    3149          *
    3150          * @param i the zero-based index of selectable items
    3151          */
    3152          public void removeAccessibleSelection(int i) {
    3153              JList.this.removeSelectionInterval(i, i);
    3154          }
    3155
    3156         /**
    3157          * Clears the selection in the object, so that nothing in the
    3158          * object is selected.
    3159          */
    3160          public void clearAccessibleSelection() {
    3161              JList.this.clearSelection();
    3162          }
    3163
    3164         /**
    3165          * Causes every selected item in the object to be selected
    3166          * if the object supports multiple selections.
    3167          */
    3168          public void selectAllAccessibleSelection() {
    3169              JList.this.addSelectionInterval(0, getAccessibleChildrenCount() -1);
    3170          }
    3171
    3172           /**
    3173            * This class implements accessibility support appropriate
    3174            * for list children.
    3175            */
    3176         protected class AccessibleJListChild extends AccessibleContext
    3177                 implements Accessible, AccessibleComponent, AccessibleAction {
    3178             private JList<E>     parent = null;
    3179             int indexInParent;
    3180             private Component component = null;
    3181             private AccessibleContext accessibleContext = null;
    3182             private ListModel<E> listModel;
    3183             private ListCellRenderer<? super E> cellRenderer = null;
    3184
    3185             /**
    3186              * Constructs an {@code AccessibleJListChild}.
    3187              * @param parent the parent
    3188              * @param indexInParent the index in the parent
    3189              */
    3190             public AccessibleJListChild(JList<E> parent, int indexInParent) {
    3191                 this.parent = parent;
    3192                 this.setAccessibleParent(parent);
    3193                 this.indexInParent = indexInParent;
    3194                 if (parent != null) {
    3195                     listModel = parent.getModel();
    3196                     cellRenderer = parent.getCellRenderer();
    3197                 }
    3198             }
    3199
    3200             private Component getCurrentComponent() {
    3201                 return getComponentAtIndex(indexInParent);
    3202             }
    3203
    3204             AccessibleContext getCurrentAccessibleContext() {
    3205                 Component c = getComponentAtIndex(indexInParent);
    3206                 if (c instanceof Accessible) {
    3207                     return c.getAccessibleContext();
    3208                 } else {
    3209                     return null;
    3210                 }
    3211             }
    3212
    3213             private Component getComponentAtIndex(int index) {
    3214                 if (index < 0 || index >= listModel.getSize()) {
    3215                     return null;
    3216                 }
    3217                 if ((parent != null)
    3218                         && (listModel != null)
    3219                         && cellRenderer != null) {
    3220                     E value = listModel.getElementAt(index);
    3221                     boolean isSelected = parent.isSelectedIndex(index);
    3222                     boolean isFocussed = parent.isFocusOwner()
    3223                             && (index == parent.getLeadSelectionIndex());
    3224                     return cellRenderer.getListCellRendererComponent(
    3225                             parent,
    3226                             value,
    3227                             index,
    3228                             isSelected,
    3229                             isFocussed);
    3230                 } else {
    3231                     return null;
    3232                 }
    3233             }
    3234
    3235
    3236             // Accessible Methods
    3237            /**
    3238             * Get the AccessibleContext for this object. In the
    3239             * implementation of the Java Accessibility API for this class,
    3240             * returns this object, which is its own AccessibleContext.
    3241             *
    3242             * @return this object
    3243             */
    3244             public AccessibleContext getAccessibleContext() {
    3245                 return this;
    3246             }
    3247
    3248
    3249             // AccessibleContext methods
    3250
    3251             public String getAccessibleName() {
    3252                 AccessibleContext ac = getCurrentAccessibleContext();
    3253                 if (ac != null) {
    3254                     return ac.getAccessibleName();
    3255                 } else {
    3256                     return null;
    3257                 }
    3258             }
    3259
    3260             public void setAccessibleName(String s) {
    3261                 AccessibleContext ac = getCurrentAccessibleContext();
    3262                 if (ac != null) {
    3263                     ac.setAccessibleName(s);
    3264                 }
    3265             }
    3266
    3267             public String getAccessibleDescription() {
    3268                 AccessibleContext ac = getCurrentAccessibleContext();
    3269                 if (ac != null) {
    3270                     return ac.getAccessibleDescription();
    3271                 } else {
    3272                     return null;
    3273                 }
    3274             }
    3275
    3276             public void setAccessibleDescription(String s) {
    3277                 AccessibleContext ac = getCurrentAccessibleContext();
    3278                 if (ac != null) {
    3279                     ac.setAccessibleDescription(s);
    3280                 }
    3281             }
    3282
    3283             public AccessibleRole getAccessibleRole() {
    3284                 AccessibleContext ac = getCurrentAccessibleContext();
    3285                 if (ac != null) {
    3286                     return ac.getAccessibleRole();
    3287                 } else {
    3288                     return null;
    3289                 }
    3290             }
    3291
    3292             public AccessibleStateSet getAccessibleStateSet() {
    3293                 AccessibleContext ac = getCurrentAccessibleContext();
    3294                 AccessibleStateSet s;
    3295                 if (ac != null) {
    3296                     s = ac.getAccessibleStateSet();
    3297                 } else {
    3298                     s = new AccessibleStateSet();
    3299                 }
    3300
    3301                 s.add(AccessibleState.SELECTABLE);
    3302                 if (parent.isFocusOwner()
    3303                     && (indexInParent == parent.getLeadSelectionIndex())) {
    3304                     s.add(AccessibleState.ACTIVE);
    3305                 }
    3306                 if (parent.isSelectedIndex(indexInParent)) {
    3307                     s.add(AccessibleState.SELECTED);
    3308                 }
    3309                 if (this.isShowing()) {
    3310                     s.add(AccessibleState.SHOWING);
    3311                 } else if (s.contains(AccessibleState.SHOWING)) {
    3312                     s.remove(AccessibleState.SHOWING);
    3313                 }
    3314                 if (this.isVisible()) {
    3315                     s.add(AccessibleState.VISIBLE);
    3316                 } else if (s.contains(AccessibleState.VISIBLE)) {
    3317                     s.remove(AccessibleState.VISIBLE);
    3318                 }
    3319                 s.add(AccessibleState.TRANSIENT); // cell-rendered
    3320                 return s;
    3321             }
    3322
    3323             public int getAccessibleIndexInParent() {
    3324                 return indexInParent;
    3325             }
    3326
    3327             public int getAccessibleChildrenCount() {
    3328                 AccessibleContext ac = getCurrentAccessibleContext();
    3329                 if (ac != null) {
    3330                     return ac.getAccessibleChildrenCount();
    3331                 } else {
    3332                     return 0;
    3333                 }
    3334             }
    3335
    3336             public Accessible getAccessibleChild(int i) {
    3337                 AccessibleContext ac = getCurrentAccessibleContext();
    3338                 if (ac != null) {
    3339                     Accessible accessibleChild = ac.getAccessibleChild(i);
    3340                     ac.setAccessibleParent(this);
    3341                     return accessibleChild;
    3342                 } else {
    3343                     return null;
    3344                 }
    3345             }
    3346
    3347             public Locale getLocale() {
    3348                 AccessibleContext ac = getCurrentAccessibleContext();
    3349                 if (ac != null) {
    3350                     return ac.getLocale();
    3351                 } else {
    3352                     return null;
    3353                 }
    3354             }
    3355
    3356             public void addPropertyChangeListener(PropertyChangeListener l) {
    3357                 AccessibleContext ac = getCurrentAccessibleContext();
    3358                 if (ac != null) {
    3359                     ac.addPropertyChangeListener(l);
    3360                 }
    3361             }
    3362
    3363             public void removePropertyChangeListener(PropertyChangeListener l) {
    3364                 AccessibleContext ac = getCurrentAccessibleContext();
    3365                 if (ac != null) {
    3366                     ac.removePropertyChangeListener(l);
    3367                 }
    3368             }
    3369
    3370            /**
    3371             * Get the AccessibleComponent associated with this object.  In the
    3372             * implementation of the Java Accessibility API for this class,
    3373             * return this object, which is responsible for implementing the
    3374             * AccessibleComponent interface on behalf of itself.
    3375             *
    3376             * @return this object
    3377             */
    3378             public AccessibleComponent getAccessibleComponent() {
    3379                 return this; // to override getBounds()
    3380             }
    3381
    3382             public AccessibleSelection getAccessibleSelection() {
    3383                 AccessibleContext ac = getCurrentAccessibleContext();
    3384                 return ac != null ? ac.getAccessibleSelection() : null;
    3385             }
    3386
    3387             public AccessibleText getAccessibleText() {
    3388                 AccessibleContext ac = getCurrentAccessibleContext();
    3389                 return ac != null ? ac.getAccessibleText() : null;
    3390             }
    3391
    3392             public AccessibleValue getAccessibleValue() {
    3393                 AccessibleContext ac = getCurrentAccessibleContext();
    3394                 return ac != null ? ac.getAccessibleValue() : null;
    3395             }
    3396
    3397
    3398             // AccessibleComponent methods
    3399
    3400             public Color getBackground() {
    3401                 AccessibleContext ac = getCurrentAccessibleContext();
    3402                 if (ac instanceof AccessibleComponent) {
    3403                     return ((AccessibleComponent) ac).getBackground();
    3404                 } else {
    3405                     Component c = getCurrentComponent();
    3406                     if (c != null) {
    3407                         return c.getBackground();
    3408                     } else {
    3409                         return null;
    3410                     }
    3411                 }
    3412             }
    3413
    3414             public void setBackground(Color c) {
    3415                 AccessibleContext ac = getCurrentAccessibleContext();
    3416                 if (ac instanceof AccessibleComponent) {
    3417                     ((AccessibleComponent) ac).setBackground(c);
    3418                 } else {
    3419                     Component cp = getCurrentComponent();
    3420                     if (cp != null) {
    3421                         cp.setBackground(c);
    3422                     }
    3423                 }
    3424             }
    3425
    3426             public Color getForeground() {
    3427                 AccessibleContext ac = getCurrentAccessibleContext();
    3428                 if (ac instanceof AccessibleComponent) {
    3429                     return ((AccessibleComponent) ac).getForeground();
    3430                 } else {
    3431                     Component c = getCurrentComponent();
    3432                     if (c != null) {
    3433                         return c.getForeground();
    3434                     } else {
    3435                         return null;
    3436                     }
    3437                 }
    3438             }
    3439
    3440             public void setForeground(Color c) {
    3441                 AccessibleContext ac = getCurrentAccessibleContext();
    3442                 if (ac instanceof AccessibleComponent) {
    3443                     ((AccessibleComponent) ac).setForeground(c);
    3444                 } else {
    3445                     Component cp = getCurrentComponent();
    3446                     if (cp != null) {
    3447                         cp.setForeground(c);
    3448                     }
    3449                 }
    3450             }
    3451
    3452             public Cursor getCursor() {
    3453                 AccessibleContext ac = getCurrentAccessibleContext();
    3454                 if (ac instanceof AccessibleComponent) {
    3455                     return ((AccessibleComponent) ac).getCursor();
    3456                 } else {
    3457                     Component c = getCurrentComponent();
    3458                     if (c != null) {
    3459                         return c.getCursor();
    3460                     } else {
    3461                         Accessible ap = getAccessibleParent();
    3462                         if (ap instanceof AccessibleComponent) {
    3463                             return ((AccessibleComponent) ap).getCursor();
    3464                         } else {
    3465                             return null;
    3466                         }
    3467                     }
    3468                 }
    3469             }
    3470
    3471             public void setCursor(Cursor c) {
    3472                 AccessibleContext ac = getCurrentAccessibleContext();
    3473                 if (ac instanceof AccessibleComponent) {
    3474                     ((AccessibleComponent) ac).setCursor(c);
    3475                 } else {
    3476                     Component cp = getCurrentComponent();
    3477                     if (cp != null) {
    3478                         cp.setCursor(c);
    3479                     }
    3480                 }
    3481             }
    3482
    3483             public Font getFont() {
    3484                 AccessibleContext ac = getCurrentAccessibleContext();
    3485                 if (ac instanceof AccessibleComponent) {
    3486                     return ((AccessibleComponent) ac).getFont();
    3487                 } else {
    3488                     Component c = getCurrentComponent();
    3489                     if (c != null) {
    3490                         return c.getFont();
    3491                     } else {
    3492                         return null;
    3493                     }
    3494                 }
    3495             }
    3496
    3497             public void setFont(Font f) {
    3498                 AccessibleContext ac = getCurrentAccessibleContext();
    3499                 if (ac instanceof AccessibleComponent) {
    3500                     ((AccessibleComponent) ac).setFont(f);
    3501                 } else {
    3502                     Component c = getCurrentComponent();
    3503                     if (c != null) {
    3504                         c.setFont(f);
    3505                     }
    3506                 }
    3507             }
    3508
    3509             public FontMetrics getFontMetrics(Font f) {
    3510                 AccessibleContext ac = getCurrentAccessibleContext();
    3511                 if (ac instanceof AccessibleComponent) {
    3512                     return ((AccessibleComponent) ac).getFontMetrics(f);
    3513                 } else {
    3514                     Component c = getCurrentComponent();
    3515                     if (c != null) {
    3516                         return c.getFontMetrics(f);
    3517                     } else {
    3518                         return null;
    3519                     }
    3520                 }
    3521             }
    3522
    3523             public boolean isEnabled() {
    3524                 AccessibleContext ac = getCurrentAccessibleContext();
    3525                 if (ac instanceof AccessibleComponent) {
    3526                     return ((AccessibleComponent) ac).isEnabled();
    3527                 } else {
    3528                     Component c = getCurrentComponent();
    3529                     if (c != null) {
    3530                         return c.isEnabled();
    3531                     } else {
    3532                         return false;
    3533                     }
    3534                 }
    3535             }
    3536
    3537             public void setEnabled(boolean b) {
    3538                 AccessibleContext ac = getCurrentAccessibleContext();
    3539                 if (ac instanceof AccessibleComponent) {
    3540                     ((AccessibleComponent) ac).setEnabled(b);
    3541                 } else {
    3542                     Component c = getCurrentComponent();
    3543                     if (c != null) {
    3544                         c.setEnabled(b);
    3545                     }
    3546                 }
    3547             }
    3548
    3549             public boolean isVisible() {
    3550                 int fi = parent.getFirstVisibleIndex();
    3551                 int li = parent.getLastVisibleIndex();
    3552                 // The UI incorrectly returns a -1 for the last
    3553                 // visible index if the list is smaller than the
    3554                 // viewport size.
    3555                 if (li == -1) {
    3556                     li = parent.getModel().getSize() - 1;
    3557                 }
    3558                 return ((indexInParent >= fi)
    3559                         && (indexInParent <= li));
    3560             }
    3561
    3562             public void setVisible(boolean b) {
    3563             }
    3564
    3565             public boolean isShowing() {
    3566                 return (parent.isShowing() && isVisible());
    3567             }
    3568
    3569             public boolean contains(Point p) {
    3570                 AccessibleContext ac = getCurrentAccessibleContext();
    3571                 if (ac instanceof AccessibleComponent) {
    3572                     Rectangle r = ((AccessibleComponent) ac).getBounds();
    3573                     return r.contains(p);
    3574                 } else {
    3575                     Component c = getCurrentComponent();
    3576                     if (c != null) {
    3577                         Rectangle r = c.getBounds();
    3578                         return r.contains(p);
    3579                     } else {
    3580                         return getBounds().contains(p);
    3581                     }
    3582                 }
    3583             }
    3584
    3585             public Point getLocationOnScreen() {
    3586                 if (parent != null) {
    3587                     Point listLocation;
    3588                     try {
    3589                         listLocation = parent.getLocationOnScreen();
    3590                     } catch (IllegalComponentStateException e) {
    3591                         // This can happen if the component isn't visisble
    3592                         return null;
    3593                     }
    3594                     Point componentLocation = parent.indexToLocation(indexInParent);
    3595                     if (componentLocation != null) {
    3596                         componentLocation.translate(listLocation.x, listLocation.y);
    3597                         return componentLocation;
    3598                     } else {
    3599                         return null;
    3600                     }
    3601                 } else {
    3602                     return null;
    3603                 }
    3604             }
    3605
    3606             public Point getLocation() {
    3607                 if (parent != null) {
    3608                     return parent.indexToLocation(indexInParent);
    3609                 } else {
    3610                     return null;
    3611                 }
    3612             }
    3613
    3614             public void setLocation(Point p) {
    3615                 if ((parent != null)  && (parent.contains(p))) {
    3616                     ensureIndexIsVisible(indexInParent);
    3617                 }
    3618             }
    3619
    3620             public Rectangle getBounds() {
    3621                 if (parent != null) {
    3622                     return parent.getCellBounds(indexInParent,indexInParent);
    3623                 } else {
    3624                     return null;
    3625                 }
    3626             }
    3627
    3628             public void setBounds(Rectangle r) {
    3629                 AccessibleContext ac = getCurrentAccessibleContext();
    3630                 if (ac instanceof AccessibleComponent) {
    3631                     ((AccessibleComponent) ac).setBounds(r);
    3632                 }
    3633             }
    3634
    3635             public Dimension getSize() {
    3636                 Rectangle cellBounds = this.getBounds();
    3637                 if (cellBounds != null) {
    3638                     return cellBounds.getSize();
    3639                 } else {
    3640                     return null;
    3641                 }
    3642             }
    3643
    3644             public void setSize (Dimension d) {
    3645                 AccessibleContext ac = getCurrentAccessibleContext();
    3646                 if (ac instanceof AccessibleComponent) {
    3647                     ((AccessibleComponent) ac).setSize(d);
    3648                 } else {
    3649                     Component c = getCurrentComponent();
    3650                     if (c != null) {
    3651                         c.setSize(d);
    3652                     }
    3653                 }
    3654             }
    3655
    3656             public Accessible getAccessibleAt(Point p) {
    3657                 AccessibleContext ac = getCurrentAccessibleContext();
    3658                 if (ac instanceof AccessibleComponent) {
    3659                     return ((AccessibleComponent) ac).getAccessibleAt(p);
    3660                 } else {
    3661                     return null;
    3662                 }
    3663             }
    3664
    3665             @SuppressWarnings("deprecation")
    3666             public boolean isFocusTraversable() {
    3667                 AccessibleContext ac = getCurrentAccessibleContext();
    3668                 if (ac instanceof AccessibleComponent) {
    3669                     return ((AccessibleComponent) ac).isFocusTraversable();
    3670                 } else {
    3671                     Component c = getCurrentComponent();
    3672                     if (c != null) {
    3673                         return c.isFocusTraversable();
    3674                     } else {
    3675                         return false;
    3676                     }
    3677                 }
    3678             }
    3679
    3680             public void requestFocus() {
    3681                 AccessibleContext ac = getCurrentAccessibleContext();
    3682                 if (ac instanceof AccessibleComponent) {
    3683                     ((AccessibleComponent) ac).requestFocus();
    3684                 } else {
    3685                     Component c = getCurrentComponent();
    3686                     if (c != null) {
    3687                         c.requestFocus();
    3688                     }
    3689                 }
    3690             }
    3691
    3692             public void addFocusListener(FocusListener l) {
    3693                 AccessibleContext ac = getCurrentAccessibleContext();
    3694                 if (ac instanceof AccessibleComponent) {
    3695                     ((AccessibleComponent) ac).addFocusListener(l);
    3696                 } else {
    3697                     Component c = getCurrentComponent();
    3698                     if (c != null) {
    3699                         c.addFocusListener(l);
    3700                     }
    3701                 }
    3702             }
    3703
    3704             public void removeFocusListener(FocusListener l) {
    3705                 AccessibleContext ac = getCurrentAccessibleContext();
    3706                 if (ac instanceof AccessibleComponent) {
    3707                     ((AccessibleComponent) ac).removeFocusListener(l);
    3708                 } else {
    3709                     Component c = getCurrentComponent();
    3710                     if (c != null) {
    3711                         c.removeFocusListener(l);
    3712                     }
    3713                 }
    3714             }
    3715
    3716             // TIGER - 4733624
    3717             /**
    3718              * Returns the icon for the element renderer, as the only item
    3719              * of an array of <code>AccessibleIcon</code>s or a <code>null</code> array
    3720              * if the renderer component contains no icons.
    3721              *
    3722              * @return an array containing the accessible icon
    3723              *         or a <code>null</code> array if none
    3724              * @since 1.3
    3725              */
    3726             public AccessibleIcon [] getAccessibleIcon() {
    3727                 AccessibleContext ac = getCurrentAccessibleContext();
    3728                 if (ac != null) {
    3729                     return ac.getAccessibleIcon();
    3730                 } else {
    3731                     return null;
    3732                 }
    3733             }
    3734
    3735             /**
    3736              * {@inheritDoc}
    3737              * @implSpec Returns the AccessibleAction for this AccessibleJListChild
    3738              * as follows:  First getListCellRendererComponent of the ListCellRenderer
    3739              * for the component at the "index in parent" of this child is called.
    3740              * Then its AccessibleContext is fetched and that AccessibleContext's
    3741              * AccessibleAction is returned.  Note that if an AccessibleAction
    3742              * is not found using this process then this object with its implementation
    3743              * of the AccessibleAction interface is returned.
    3744              * @since 9
    3745              */
    3746             @Override
    3747             public AccessibleAction getAccessibleAction() {
    3748                 AccessibleContext ac = getCurrentAccessibleContext();
    3749                 if (ac == null) {
    3750                     return null;
    3751                 } else {
    3752                     AccessibleAction aa = ac.getAccessibleAction();
    3753                     if (aa != null) {
    3754                         return aa;
    3755                     } else {
    3756                         return this;
    3757                     }
    3758                 }
    3759             }
    3760
    3761             /**
    3762              * {@inheritDoc}
    3763              * @implSpec If i == 0 selects this AccessibleJListChild by calling
    3764              * JList.this.setSelectedIndex(indexInParent) and then returns true;
    3765              * otherwise returns false.
    3766              * @since 9
    3767              */
    3768             @Override
    3769             public boolean doAccessibleAction(int i) {
    3770                 if (i == 0) {
    3771                     JList.this.setSelectedIndex(indexInParent);
    3772                     return true;
    3773                 } else {
    3774                     return false;
    3775                 }
    3776             }
    3777
    3778             /**
    3779              * {@inheritDoc}
    3780              * @implSpec If i == 0 returns the action description fetched from
    3781              * UIManager.getString("AbstractButton.clickText");
    3782              * otherwise returns null.
    3783              * @since 9
    3784              */
    3785             @Override
    3786             public String getAccessibleActionDescription(int i) {
    3787                 if (i == 0) {
    3788                     return UIManager.getString("AbstractButton.clickText");
    3789                 } else {
    3790                     return null;
    3791                 }
    3792             }
    3793
    3794             /**
    3795              * {@inheritDoc}
    3796              * @implSpec Returns 1, i.e. there is only one action.
    3797              * @since 9
    3798              */
    3799             @Override
    3800             public int getAccessibleActionCount() {
    3801                 return 1;
    3802             }
    3803
    3804         } // inner class AccessibleJListChild
    3805
    3806     } // inner class AccessibleJList
    3807 }
    --- EOF ---