Name: rmT116609 Date: 07/24/2001


java version "1.4.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b65)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b65, mixed mode)


I have a JTable in a JScrollPane, when the table is big enough to make the
scrollbar appear, then if I move the mouse over the table I get a NullPointer exception.
The stacktrace:

java.lang.NullPointerException
at javax.swing.text.View.getViewIndex(View.java:1060)
at javax.swing.text.View.getToolTipText(View.java:1031)
at javax.swing.plaf.basic.BasicTextUI.getToolTipText(BasicTextUI.java:1057)
at javax.swing.text.JTextComponent.getToolTipText(JTextComponent.java:1533)
at javax.swing.JTable.getToolTipText(JTable.java:2380)
at
javax.swing.ToolTipManager$insideTimerAction.actionPerformed(ToolTipManager.java:669)
at javax.swing.Timer.fireActionPerformed(Timer.java:256)
at javax.swing.Timer$DoPostEvent.run(Timer.java:190)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:167)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:437)
at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:131)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)

There are three files included. In fact two bugs occur:

1. if I use the setRowHeight(int, int) and then add a new row to the table, the table is
not repainted correctly
2. if I use the special CellRenderer, then I get the NullPointerException

These bugs are reproduced as follows:

1. compile and run 'Test'
2. at first a table with 6 rows and 4 columns is shown.
3. press the button 'change model' --> a new row should show up, but it doesn't.
4. move the mouse over the table, near a gridline --> an NPE occurs

Linux version:
RedHat 7.1 kernel 2.4.2

The problem is NOT reproducable with java 1.3.1

----------------------------Test.java--------------------------------------
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

public class Test {
  public static void main (String[] args) {
    JFrame frame = new JFrame();
    frame.setSize(new Dimension(400, 400));
    frame.getContentPane().add(getTable());
    frame.show();
  }

  private static JComponent getTable() {
    JPanel result = new JPanel();
    result.setLayout(new BorderLayout());
    final TestTable table = new TestTable();
    JComponent scrollPane = new JScrollPane(table);
    result.add(scrollPane, BorderLayout.CENTER);
    final DefaultTableModel model = new DefaultTableModel();
    updateTableModel(table, model, 4,6);
    table.setModel(model);
    JButton button = new JButton("change model");
    button.addActionListener(new ActionListener() {
      int i = 6;
      public void actionPerformed(ActionEvent e) {
        updateTableModel(table, model, 4,++i);
      }
    });
    result.add(button, BorderLayout.SOUTH);
    return result;
  }

  private static void updateTableModel(JTable table, DefaultTableModel model, int columns, int rows) {
    Vector data = new Vector();
    Vector columndata = new Vector();
    for (int i = 0; i < rows; i++) {
      Vector v = new Vector();
      for (int j = 0; j < columns; j++) {
        v.add(i + ", " + j + (i == 2?"":"\n\n"));
      }
      data.add(v);
    }
    for (int i = 0; i < columns; i++) {
      columndata.add(String.valueOf(i));
    }
    model.setDataVector(data, columndata);
  }
} // End of Test.java

----------------------TestTableCellRenderer.java----------------------------
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.border.*;
import java.awt.Component;
import java.util.*;
import java.text.DateFormat;


public class TestTableCellRenderer extends JTextArea implements TableCellRenderer {
  public TestTableCellRenderer() {
    super.setEditable(false);
    setBorder(new EmptyBorder(1, 1, 1, 1));
  }

  public Component getTableCellRendererComponent(JTable table, Object value,
                                                 boolean isSelected, boolean hasFocus,
                                                 int row, int column) {
    if (value == null) {
      setText("");
    } else {
      setText(String.valueOf(value));
    }

    if (isSelected) {
      setForeground(table.getSelectionForeground());
      setBackground(table.getSelectionBackground());
    } else {
      setForeground(table.getForeground());
      setBackground(table.getBackground());
    }
      
    int height = getPreferredSize().height;
    ((TestTable) table).updateRowHeight(row, column, height);
    return this;
  }

} // End of TestTableCellRenderer.java

----------------------------TestTable.java-----------------------------------
import javax.swing.*;
import javax.swing.table.*;
import java.util.*;

public class TestTable extends JTable {
  List cellHeights = new ArrayList();
  TableCellRenderer c = new TestTableCellRenderer();

  public void updateRowHeight(int row, int column, int height) {
    while (cellHeights.size() <= row) {
      int [] newArray = new int[getColumnCount()];
      Arrays.fill(newArray, 0);
      cellHeights.add(newArray);
    }
    int [] rowHeights = (int []) cellHeights.get(row);
    rowHeights[column] = height;
    int maxHeight = 17;
    for (int i = 0; i < getColumnCount(); i++) {
      maxHeight = Math.max(maxHeight, rowHeights[i]);
    }
    if (getRowHeight(row) != maxHeight) {
      setRowHeight(row, maxHeight);
    }
  }

  public TableCellRenderer getCellRenderer(int row, int col) {
    return c;
  }
} //TestTable.java
(Review ID: 128325)
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