Name: jk109818 Date: 07/11/2000


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)

Application still dead locks when displaying a JOptionPane whilst performing
drag and drop. Interstingly when run from the command line control-c no longer
kills the application - it now enters a tight loop consuming all of the CPU!
(On 1.2.2_05a at least control-c ends the app!).

Run the following app:

    java DNDLock lock - will kill it
    java DNDLock - works round it

////////////////////////////
// code starts
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import java.awt.dnd.*;
import javax.swing.*;
import javax.swing.border.*;

/** Deadlock within 1.3. JOptionPane within DND method = death.<p>
 ** Workround use SwingUtilities.invokeLater.
 **/
public class DNDLock extends JFrame
{
    private static boolean m_showingDialog = false;
    private static boolean m_performLockup = false;
    public static void main(String[] args)
    {
        DNDLock application = new DNDLock("SERVICEPower DND Lock-up
Application: Displaying Dialogs");

if(args.length == 1)
        {
if(args[0].equals("lock"))
            {
m_performLockup = true;
            }
        }
        application.show();
        return;
    }

    /** Ctor sets up the basic dialog **/
    public DNDLock(final String title)
    {
        super(title);
        getContentPane().add(m_mainPanel);
        m_mainPanel.add(m_centrePanel, BorderLayout.CENTER);

        // handle the frame's close button being pressed
        java.awt.event.WindowListener l = new java.awt.event.WindowAdapter()
{
            public void windowClosing(java.awt.event.WindowEvent event)
            {
                System.err.println("DNDLock ended");
                System.exit(0);
            }
        };

        addWindowListener(l);
        setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
        setSize(500, 250);

        m_centrePanel.add(m_fifthObject);
    }

    private JPanel m_mainPanel = new JPanel(new BorderLayout());
    private DropPanel m_centrePanel = new DropPanel(Color.black, "Centre");

    private DraggableObject m_fifthObject = new DraggableObject("DRAG OBJECT
5", m_centrePanel);

    /**************************************************************************
     ** DropPanel <p>
     ** Instances of this are available as drop targets, in this application
     ** they simply display some text to state where they are up to.
     **************************************************************************/
    public class DropPanel extends JPanel implements DropTargetListener
    {

        public DropPanel(final Color color, final String name)
        {
            m_name = name;
            setBorder(BorderFactory.createLineBorder(color));
            m_dropTarget = new DropTarget(this, this);
        }
        ///////////////////////////////////////////////////////////////////////
        // DropTargetListener implementation
        public void dragEnter(DropTargetDragEvent dtde)
        {
            System.err.println(m_name + " - dragEnter");
            m_draggingHere = true;
            setCurrentDragBounds(dtde.getLocation());
            dtde.acceptDrag(dtde.getSourceActions());
        }
/** This processing as invokeLater works with 1.3, and 1.2.2_05a but
not with 1.2.2-W **/
        public void dragOver(DropTargetDragEvent dtde)
        {
            System.err.println(m_name + " - dragOver");
            setCurrentDragBounds(dtde.getLocation());

            dtde.acceptDrag(dtde.getSourceActions());

if(m_performLockup)
            {
JOptionPane.showMessageDialog(null, "Has this locked the
application?", "Are we locked", JOptionPane.QUESTION_MESSAGE);
}
else
{
if(!DNDLock.m_showingDialog)
{
DNDLock.m_showingDialog = true;
SwingUtilities.invokeLater(new Runnable()
   {
public void run()
{
JOptionPane.showMessageDialog(null, "Has this
locked the application?", "Are we locked", JOptionPane.QUESTION_MESSAGE);
DNDLock.m_showingDialog = false;
}
});
}
  }
            repaint();
        }

        public void dropActionChanged(DropTargetDragEvent dtde)
        {
            System.err.println(m_name + " - dropActionChanged");
            setCurrentDragBounds(dtde.getLocation());
        }

        public void dragExit(DropTargetEvent dte)
        {
            System.err.println(m_name + " - dragExit");
            m_draggingHere = false;
        }

        public void drop(DropTargetDropEvent dtde)
        {
            System.err.println(m_name + " - drop");
            setCurrentDragBounds(dtde.getLocation());
            dtde.rejectDrop();
dtde.dropComplete(true);
            m_draggingHere = false;
        }

        /** It is not necessary to include any of your own drawing code to get
the application to lock.
         ** This code is included because it is similar in spirit to our core
application. **/
        public void paintComponent(Graphics g)
        {
            super.paintComponent(g);
            paintDrag(g, m_draggingHere);
        }

        /** As for paintComponent, this is not needed to hang the application.
**/
        public void paintDrag(Graphics g, boolean dragging)
        {
            Rectangle rect = (Rectangle)m_repaintRect.clone();
            Graphics2D g2 = (Graphics2D) g;
            Color oldColor = g.getColor();
            if(dragging)
            {
                g2.setColor(Color.yellow);
            }
            else
            {
                g2.setColor(Color.lightGray);
            }
            Stroke s = g2.getStroke();
            g2.setStroke(m_rectStroke);
            g2.draw(rect);
            g2.setColor(oldColor);
            g2.setStroke(s);
        }

        private void setCurrentDragBounds(final Point location)
        {
            // repaint rectangle
            m_repaintRect.x = location.x;
            m_repaintRect.y = location.y;
            m_repaintRect.width = 100;
            m_repaintRect.height = 50;
        }

        private Rectangle m_repaintRect = new Rectangle();

        private boolean m_draggingHere = false;
        private final String m_name;
        private DropTarget m_dropTarget;
        private final float[] dash1 = {10.0f};
        private BasicStroke m_rectStroke = new BasicStroke(3.0f,
BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER, 10.0f, dash1, 0.0f);

    }

    /**************************************************************************
     ** DraggableObject <p>
     ** Instances of this JComponent derivations are used as draggable objects
     ** within the core application. Here I use a JLabel for simplicity.
     **************************************************************************/
    public class DraggableObject extends JLabel
                                 implements DragSourceListener,
DragGestureListener, Transferable
    {
        public DraggableObject(final String name, JPanel owner)
        {
            setText(name);
            setBorder(BorderFactory.createBevelBorder(BevelBorder.LOWERED));
            m_owner = owner;
            m_name = name;
            m_dragSource = DragSource.getDefaultDragSource();
            m_dragComponent = this;

            m_gestureRecogniser =
m_dragSource.createDefaultDragGestureRecognizer(m_dragComponent,
DnDConstants.ACTION_COPY_OR_MOVE, this);
        }
        ///////////////////////////////////////////////////////////////////////
        // DragSourceListener implementation
     public void dragDropEnd(DragSourceDropEvent dsde)
     {
            System.err.println(m_name + " - dragDropEnd: " + dsde.getDropSuccess
());
            
            m_owner.repaint();
            m_owner.revalidate();
     }

      public void dragEnter(DragSourceDragEvent dsde)
      {
            System.err.println(m_name + " - dragEnter");
      }

     public void dragExit(DragSourceEvent dse)
     {
            System.err.println(m_name + " - dragExit");
     }

     public void dragOver(DragSourceDragEvent dsde)
     {
            System.err.println(m_name + " - dragOver");
     }

        /** It is not necessary to include any of your own drawing code to get
the application to lock.
         ** This code is included because it is similar in spirit to our core
application. **/
        public void paintComponent1(Graphics g)
        {
            super.paintComponent(g);
            m_owner.repaint();
        }

     public void dropActionChanged(DragSourceDragEvent dsde)
     {
            System.err.println(m_name + " - dropActionChanged");
     }
        ///////////////////////////////////////////////////////////////////////
        // DragGestureListener implementation
        public void dragGestureRecognized(DragGestureEvent dge)
     {
            System.err.println(m_name + " - dragGestureRecognized");
            // we're in a valid drag situation
            dge.startDrag(DragSource.DefaultMoveDrop, this, this);
     }
        ///////////////////////////////////////////////////////////////////////
        // Transferable implementation
        public DataFlavor[] getTransferDataFlavors()
        {
            DataFlavor[] flavours = { DRAG_FLAVOUR };
            return flavours;
        }
        public boolean isDataFlavorSupported(DataFlavor flavour)
        {
            return flavour.equals(DRAG_FLAVOUR);
        }
        public Object getTransferData(DataFlavor flavor) throws
UnsupportedFlavorException, IOException
        {
            return new String(m_name + " transferData");
        }

        private JPanel m_owner;
        private String m_name;
        private DragSource m_dragSource;
        private DragGestureRecognizer m_gestureRecogniser;
        private JComponent m_dragComponent;
    }

    ///////////////////////////////////////////////////////////////////////////
    // DataFlavor stuff for DragGesture implementation
public static DataFlavor DRAG_FLAVOUR = new DataFlavor
(DragFlavour.class, "DragFlavor");
    public class DragFlavour
    {
        public DragFlavour()
        {
        }
    }

}

// code ends
////////////////////////////
(Review ID: 107069)
======================================================================