jdk/src/share/classes/sun/awt/dnd/SunDropTargetContextPeer.java
changeset 2 90ce3da70b43
child 3938 ef327bd847c0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/awt/dnd/SunDropTargetContextPeer.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,903 @@
+/*
+ * Copyright 2000-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package sun.awt.dnd;
+
+import java.awt.Component;
+import java.awt.Point;
+
+import java.awt.datatransfer.DataFlavor;
+import java.awt.datatransfer.Transferable;
+import java.awt.datatransfer.UnsupportedFlavorException;
+
+import java.awt.dnd.DnDConstants;
+
+import java.awt.dnd.DropTarget;
+import java.awt.dnd.DropTargetContext;
+import java.awt.dnd.DropTargetListener;
+import java.awt.dnd.DropTargetEvent;
+import java.awt.dnd.DropTargetDragEvent;
+import java.awt.dnd.DropTargetDropEvent;
+import java.awt.dnd.InvalidDnDOperationException;
+
+import java.awt.dnd.peer.DropTargetContextPeer;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Arrays;
+
+import java.util.logging.*;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import sun.awt.AppContext;
+import sun.awt.SunToolkit;
+import sun.awt.datatransfer.DataTransferer;
+import sun.awt.datatransfer.ToolkitThreadBlockedHandler;
+
+/**
+ * <p>
+ * The SunDropTargetContextPeer class is the generic class responsible for handling
+ * the interaction between a windowing systems DnD system and Java.
+ * </p>
+ *
+ * @since JDK1.3.1
+ *
+ */
+
+public abstract class SunDropTargetContextPeer implements DropTargetContextPeer, Transferable {
+
+    /*
+     * A boolean constant that requires the peer to wait until the
+     * SunDropTargetEvent is processed and return the status back
+     * to the native code.
+     */
+    public static final boolean DISPATCH_SYNC = true;
+    private   DropTarget              currentDT;
+    private   DropTargetContext       currentDTC;
+    private   long[]                  currentT;
+    private   int                     currentA;   // target actions
+    private   int                     currentSA;  // source actions
+    private   int                     currentDA;  // current drop action
+    private   int                     previousDA;
+
+    private   long                    nativeDragContext;
+
+    private   Transferable            local;
+
+    private boolean                   dragRejected = false;
+
+    protected int                     dropStatus   = STATUS_NONE;
+    protected boolean                 dropComplete = false;
+
+    /*
+     * global lock
+     */
+
+    protected static final Object _globalLock = new Object();
+
+    private static final Logger dndLog = Logger.getLogger("sun.awt.dnd.SunDropTargetContextPeer");
+
+    /*
+     * a primitive mechanism for advertising intra-JVM Transferables
+     */
+
+    protected static Transferable         currentJVMLocalSourceTransferable = null;
+
+    public static void setCurrentJVMLocalSourceTransferable(Transferable t) throws InvalidDnDOperationException {
+        synchronized(_globalLock) {
+            if (t != null && currentJVMLocalSourceTransferable != null) {
+                    throw new InvalidDnDOperationException();
+            } else {
+                currentJVMLocalSourceTransferable = t;
+            }
+        }
+    }
+
+    /**
+     * obtain the transferable iff the operation is in the same VM
+     */
+
+    private static Transferable getJVMLocalSourceTransferable() {
+        return currentJVMLocalSourceTransferable;
+    }
+
+    /*
+     * constants used by dropAccept() or dropReject()
+     */
+
+    protected final static int STATUS_NONE   =  0; // none pending
+    protected final static int STATUS_WAIT   =  1; // drop pending
+    protected final static int STATUS_ACCEPT =  2;
+    protected final static int STATUS_REJECT = -1;
+
+    /**
+     * create the peer
+     */
+
+    public SunDropTargetContextPeer() {
+        super();
+    }
+
+    /**
+     * @return the DropTarget associated with this peer
+     */
+
+    public DropTarget getDropTarget() { return currentDT; }
+
+    /**
+     * @param actions set the current actions
+     */
+
+    public synchronized void setTargetActions(int actions) {
+        currentA = actions &
+            (DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK);
+    }
+
+    /**
+     * @return the current target actions
+     */
+
+    public int getTargetActions() {
+        return currentA;
+    }
+
+    /**
+     * get the Transferable associated with the drop
+     */
+
+    public Transferable getTransferable() {
+        return this;
+    }
+
+    /**
+     * @return current DataFlavors available
+     */
+    // NOTE: This method may be called by privileged threads.
+    //       DO NOT INVOKE CLIENT CODE ON THIS THREAD!
+
+    public DataFlavor[] getTransferDataFlavors() {
+        final Transferable    localTransferable = local;
+
+        if (localTransferable != null) {
+            return localTransferable.getTransferDataFlavors();
+        } else {
+            return DataTransferer.getInstance().getFlavorsForFormatsAsArray
+                (currentT, DataTransferer.adaptFlavorMap
+                    (currentDT.getFlavorMap()));
+        }
+    }
+
+    /**
+     * @return if the flavor is supported
+     */
+
+    public boolean isDataFlavorSupported(DataFlavor df) {
+        Transferable localTransferable = local;
+
+        if (localTransferable != null) {
+            return localTransferable.isDataFlavorSupported(df);
+        } else {
+            return DataTransferer.getInstance().getFlavorsForFormats
+                (currentT, DataTransferer.adaptFlavorMap
+                    (currentDT.getFlavorMap())).
+                containsKey(df);
+        }
+    }
+
+    /**
+     * @return the data
+     */
+
+    public Object getTransferData(DataFlavor df)
+      throws UnsupportedFlavorException, IOException,
+        InvalidDnDOperationException
+    {
+        Long lFormat = null;
+        Transferable localTransferable = local;
+
+        if (localTransferable != null) {
+            return localTransferable.getTransferData(df);
+        }
+
+        if (dropStatus != STATUS_ACCEPT || dropComplete) {
+            throw new InvalidDnDOperationException("No drop current");
+        }
+
+        Map flavorMap = DataTransferer.getInstance().getFlavorsForFormats
+            (currentT, DataTransferer.adaptFlavorMap
+                (currentDT.getFlavorMap()));
+
+        lFormat = (Long)flavorMap.get(df);
+        if (lFormat == null) {
+            throw new UnsupportedFlavorException(df);
+        }
+
+        if (df.isRepresentationClassRemote() &&
+            currentDA != DnDConstants.ACTION_LINK) {
+            throw new InvalidDnDOperationException("only ACTION_LINK is permissable for transfer of java.rmi.Remote objects");
+        }
+
+        final long format = lFormat.longValue();
+        Object ret = getNativeData(format);
+
+        if (ret instanceof byte[]) {
+            try {
+                return DataTransferer.getInstance().
+                    translateBytes((byte[])ret, df, format, this);
+            } catch (IOException e) {
+                throw new InvalidDnDOperationException(e.getMessage());
+            }
+        } else if (ret instanceof InputStream) {
+            try {
+                return DataTransferer.getInstance().
+                    translateStream((InputStream)ret, df, format, this);
+            } catch (IOException e) {
+                throw new InvalidDnDOperationException(e.getMessage());
+            }
+        } else {
+            throw new IOException("no native data was transfered");
+        }
+    }
+
+    protected abstract Object getNativeData(long format)
+      throws IOException;
+
+    /**
+     * @return if the transfer is a local one
+     */
+    public boolean isTransferableJVMLocal() {
+        return local != null || getJVMLocalSourceTransferable() != null;
+    }
+
+    private int handleEnterMessage(final Component component,
+                                   final int x, final int y,
+                                   final int dropAction,
+                                   final int actions, final long[] formats,
+                                   final long nativeCtxt) {
+        return postDropTargetEvent(component, x, y, dropAction, actions,
+                                   formats, nativeCtxt,
+                                   SunDropTargetEvent.MOUSE_ENTERED,
+                                   SunDropTargetContextPeer.DISPATCH_SYNC);
+    }
+
+    /**
+     * actual processing on EventQueue Thread
+     */
+
+    protected void processEnterMessage(SunDropTargetEvent event) {
+        Component  c    = (Component)event.getSource();
+        DropTarget dt   = c.getDropTarget();
+        Point      hots = event.getPoint();
+
+        local = getJVMLocalSourceTransferable();
+
+        if (currentDTC != null) { // some wreckage from last time
+            currentDTC.removeNotify();
+            currentDTC = null;
+        }
+
+        if (c.isShowing() && dt != null && dt.isActive()) {
+            currentDT  = dt;
+            currentDTC = currentDT.getDropTargetContext();
+
+            currentDTC.addNotify(this);
+
+            currentA   = dt.getDefaultActions();
+
+            try {
+                ((DropTargetListener)dt).dragEnter(new DropTargetDragEvent(currentDTC,
+                                                                           hots,
+                                                                           currentDA,
+                                                                           currentSA));
+            } catch (Exception e) {
+                e.printStackTrace();
+                currentDA = DnDConstants.ACTION_NONE;
+            }
+        } else {
+            currentDT  = null;
+            currentDTC = null;
+            currentDA   = DnDConstants.ACTION_NONE;
+            currentSA   = DnDConstants.ACTION_NONE;
+            currentA   = DnDConstants.ACTION_NONE;
+        }
+
+    }
+
+    /**
+     * upcall to handle exit messages
+     */
+
+    private void handleExitMessage(final Component component,
+                                   final long nativeCtxt) {
+        /*
+         * Even though the return value is irrelevant for this event, it is
+         * dispatched synchronously to fix 4393148 properly.
+         */
+        postDropTargetEvent(component, 0, 0, DnDConstants.ACTION_NONE,
+                            DnDConstants.ACTION_NONE, null, nativeCtxt,
+                            SunDropTargetEvent.MOUSE_EXITED,
+                            SunDropTargetContextPeer.DISPATCH_SYNC);
+    }
+
+    /**
+     *
+     */
+
+    protected void processExitMessage(SunDropTargetEvent event) {
+        Component         c   = (Component)event.getSource();
+        DropTarget        dt  = c.getDropTarget();
+        DropTargetContext dtc = null;
+
+        if (dt == null) {
+            currentDT = null;
+            currentT  = null;
+
+            if (currentDTC != null) {
+                currentDTC.removeNotify();
+            }
+
+            currentDTC = null;
+
+            return;
+        }
+
+        if (dt != currentDT) {
+
+            if (currentDTC != null) {
+                currentDTC.removeNotify();
+            }
+
+            currentDT  = dt;
+            currentDTC = dt.getDropTargetContext();
+
+            currentDTC.addNotify(this);
+        }
+
+        dtc = currentDTC;
+
+        if (dt.isActive()) try {
+            ((DropTargetListener)dt).dragExit(new DropTargetEvent(dtc));
+        } catch (Exception e) {
+            e.printStackTrace();
+        } finally {
+            currentA  = DnDConstants.ACTION_NONE;
+            currentSA = DnDConstants.ACTION_NONE;
+            currentDA = DnDConstants.ACTION_NONE;
+            currentDT = null;
+            currentT  = null;
+
+            currentDTC.removeNotify();
+            currentDTC = null;
+
+            local = null;
+
+            dragRejected = false;
+        }
+    }
+
+    private int handleMotionMessage(final Component component,
+                                    final int x, final int y,
+                                    final int dropAction,
+                                    final int actions, final long[] formats,
+                                    final long nativeCtxt) {
+        return postDropTargetEvent(component, x, y, dropAction, actions,
+                                   formats, nativeCtxt,
+                                   SunDropTargetEvent.MOUSE_DRAGGED,
+                                   SunDropTargetContextPeer.DISPATCH_SYNC);
+    }
+
+    /**
+     *
+     */
+
+    protected void processMotionMessage(SunDropTargetEvent event,
+                                      boolean operationChanged) {
+        Component         c    = (Component)event.getSource();
+        Point             hots = event.getPoint();
+        int               id   = event.getID();
+        DropTarget        dt   = c.getDropTarget();
+        DropTargetContext dtc  = null;
+
+        if (c.isShowing() && (dt != null) && dt.isActive()) {
+            if (currentDT != dt) {
+                if (currentDTC != null) {
+                    currentDTC.removeNotify();
+                }
+
+                currentDT  = dt;
+                currentDTC = null;
+            }
+
+            dtc = currentDT.getDropTargetContext();
+            if (dtc != currentDTC) {
+                if (currentDTC != null) {
+                    currentDTC.removeNotify();
+                }
+
+                currentDTC = dtc;
+                currentDTC.addNotify(this);
+            }
+
+            currentA = currentDT.getDefaultActions();
+
+            try {
+                DropTargetDragEvent dtde = new DropTargetDragEvent(dtc,
+                                                                   hots,
+                                                                   currentDA,
+                                                                   currentSA);
+                DropTargetListener dtl = (DropTargetListener)dt;
+                if (operationChanged) {
+                    dtl.dropActionChanged(dtde);
+                } else {
+                    dtl.dragOver(dtde);
+                }
+
+                if (dragRejected) {
+                    currentDA = DnDConstants.ACTION_NONE;
+                }
+            } catch (Exception e) {
+                e.printStackTrace();
+                currentDA = DnDConstants.ACTION_NONE;
+            }
+        } else {
+            currentDA = DnDConstants.ACTION_NONE;
+        }
+    }
+
+    /**
+     * upcall to handle the Drop message
+     */
+
+    private void handleDropMessage(final Component component,
+                                   final int x, final int y,
+                                   final int dropAction, final int actions,
+                                   final long[] formats,
+                                   final long nativeCtxt) {
+        postDropTargetEvent(component, x, y, dropAction, actions,
+                            formats, nativeCtxt,
+                            SunDropTargetEvent.MOUSE_DROPPED,
+                            !SunDropTargetContextPeer.DISPATCH_SYNC);
+    }
+
+    /**
+     *
+     */
+
+    protected void processDropMessage(SunDropTargetEvent event) {
+        Component  c    = (Component)event.getSource();
+        Point      hots = event.getPoint();
+        DropTarget dt   = c.getDropTarget();
+
+        dropStatus   = STATUS_WAIT; // drop pending ACK
+        dropComplete = false;
+
+        if (c.isShowing() && dt != null && dt.isActive()) {
+            DropTargetContext dtc = dt.getDropTargetContext();
+
+            currentDT = dt;
+
+            if (currentDTC != null) {
+                currentDTC.removeNotify();
+            }
+
+            currentDTC = dtc;
+            currentDTC.addNotify(this);
+            currentA = dt.getDefaultActions();
+
+            synchronized(_globalLock) {
+                if ((local = getJVMLocalSourceTransferable()) != null)
+                    setCurrentJVMLocalSourceTransferable(null);
+            }
+
+            try {
+                ((DropTargetListener)dt).drop(new DropTargetDropEvent(dtc,
+                                                                      hots,
+                                                                      currentDA,
+                                                                      currentSA,
+                                                                      local != null));
+            } finally {
+                if (dropStatus == STATUS_WAIT) {
+                    rejectDrop();
+                } else if (dropComplete == false) {
+                    dropComplete(false);
+                }
+            }
+        } else {
+            rejectDrop();
+        }
+    }
+
+    protected int postDropTargetEvent(final Component component,
+                                      final int x, final int y,
+                                      final int dropAction,
+                                      final int actions,
+                                      final long[] formats,
+                                      final long nativeCtxt,
+                                      final int eventID,
+                                      final boolean dispatchType) {
+        AppContext appContext = SunToolkit.targetToAppContext(component);
+
+        EventDispatcher dispatcher =
+            new EventDispatcher(this, dropAction, actions, formats, nativeCtxt,
+                                dispatchType);
+
+        SunDropTargetEvent event =
+            new SunDropTargetEvent(component, eventID, x, y, dispatcher);
+
+        if (dispatchType == SunDropTargetContextPeer.DISPATCH_SYNC) {
+            DataTransferer.getInstance().getToolkitThreadBlockedHandler().lock();
+        }
+
+        // schedule callback
+        SunToolkit.postEvent(appContext, event);
+
+        eventPosted(event);
+
+        if (dispatchType == SunDropTargetContextPeer.DISPATCH_SYNC) {
+            while (!dispatcher.isDone()) {
+                DataTransferer.getInstance().getToolkitThreadBlockedHandler().enter();
+            }
+
+            DataTransferer.getInstance().getToolkitThreadBlockedHandler().unlock();
+
+            // return target's response
+            return dispatcher.getReturnValue();
+        } else {
+            return 0;
+        }
+    }
+
+    /**
+     * acceptDrag
+     */
+
+    public synchronized void acceptDrag(int dragOperation) {
+        if (currentDT == null) {
+            throw new InvalidDnDOperationException("No Drag pending");
+        }
+        currentDA = mapOperation(dragOperation);
+        if (currentDA != DnDConstants.ACTION_NONE) {
+            dragRejected = false;
+        }
+    }
+
+    /**
+     * rejectDrag
+     */
+
+    public synchronized void rejectDrag() {
+        if (currentDT == null) {
+            throw new InvalidDnDOperationException("No Drag pending");
+        }
+        currentDA = DnDConstants.ACTION_NONE;
+        dragRejected = true;
+    }
+
+    /**
+     * acceptDrop
+     */
+
+    public synchronized void acceptDrop(int dropOperation) {
+        if (dropOperation == DnDConstants.ACTION_NONE)
+            throw new IllegalArgumentException("invalid acceptDrop() action");
+
+        if (dropStatus != STATUS_WAIT) {
+            throw new InvalidDnDOperationException("invalid acceptDrop()");
+        }
+
+        currentDA = currentA = mapOperation(dropOperation & currentSA);
+
+        dropStatus   = STATUS_ACCEPT;
+        dropComplete = false;
+    }
+
+    /**
+     * reject Drop
+     */
+
+    public synchronized void rejectDrop() {
+        if (dropStatus != STATUS_WAIT) {
+            throw new InvalidDnDOperationException("invalid rejectDrop()");
+        }
+        dropStatus = STATUS_REJECT;
+        /*
+         * Fix for 4285634.
+         * The target rejected the drop means that it doesn't perform any
+         * drop action. This change is to make Solaris behavior consistent
+         * with Win32.
+         */
+        currentDA = DnDConstants.ACTION_NONE;
+        dropComplete(false);
+    }
+
+    /**
+     * mapOperation
+     */
+
+    private int mapOperation(int operation) {
+        int[] operations = {
+                DnDConstants.ACTION_MOVE,
+                DnDConstants.ACTION_COPY,
+                DnDConstants.ACTION_LINK,
+        };
+        int   ret = DnDConstants.ACTION_NONE;
+
+        for (int i = 0; i < operations.length; i++) {
+            if ((operation & operations[i]) == operations[i]) {
+                    ret = operations[i];
+                    break;
+            }
+        }
+
+        return ret;
+    }
+
+    /**
+     * signal drop complete
+     */
+
+    public synchronized void dropComplete(boolean success) {
+        if (dropStatus == STATUS_NONE) {
+            throw new InvalidDnDOperationException("No Drop pending");
+        }
+
+        if (currentDTC != null) currentDTC.removeNotify();
+
+        currentDT  = null;
+        currentDTC = null;
+        currentT   = null;
+        currentA   = DnDConstants.ACTION_NONE;
+
+        synchronized(_globalLock) {
+            currentJVMLocalSourceTransferable = null;
+        }
+
+        dropStatus   = STATUS_NONE;
+        dropComplete = true;
+
+        try {
+            doDropDone(success, currentDA, local != null);
+        } finally {
+            currentDA = DnDConstants.ACTION_NONE;
+            // The native context is invalid after the drop is done.
+            // Clear the reference to prohibit access.
+            nativeDragContext = 0;
+        }
+    }
+
+    protected abstract void doDropDone(boolean success,
+                                       int dropAction, boolean isLocal);
+
+    protected synchronized long getNativeDragContext() {
+        return nativeDragContext;
+    }
+
+    protected void eventPosted(SunDropTargetEvent e) {}
+
+    protected void eventProcessed(SunDropTargetEvent e, int returnValue,
+                                  boolean dispatcherDone) {}
+
+    protected static class EventDispatcher {
+
+        private final SunDropTargetContextPeer peer;
+
+        // context fields
+        private final int dropAction;
+        private final int actions;
+        private final long[] formats;
+        private long nativeCtxt;
+        private final boolean dispatchType;
+        private boolean dispatcherDone = false;
+
+        // dispatcher state fields
+        private int returnValue = 0;
+        // set of events to be dispatched by this dispatcher
+        private final HashSet eventSet = new HashSet(3);
+
+        static final ToolkitThreadBlockedHandler handler =
+            DataTransferer.getInstance().getToolkitThreadBlockedHandler();
+
+        EventDispatcher(SunDropTargetContextPeer peer,
+                        int dropAction,
+                        int actions,
+                        long[] formats,
+                        long nativeCtxt,
+                        boolean dispatchType) {
+
+            this.peer         = peer;
+            this.nativeCtxt   = nativeCtxt;
+            this.dropAction   = dropAction;
+            this.actions      = actions;
+            this.formats =
+                     (null == formats) ? null : Arrays.copyOf(formats, formats.length);
+            this.dispatchType = dispatchType;
+        }
+
+        void dispatchEvent(SunDropTargetEvent e) {
+            int id = e.getID();
+
+            switch (id) {
+            case SunDropTargetEvent.MOUSE_ENTERED:
+                dispatchEnterEvent(e);
+                break;
+            case SunDropTargetEvent.MOUSE_DRAGGED:
+                dispatchMotionEvent(e);
+                break;
+            case SunDropTargetEvent.MOUSE_EXITED:
+                dispatchExitEvent(e);
+                break;
+            case SunDropTargetEvent.MOUSE_DROPPED:
+                dispatchDropEvent(e);
+                break;
+            default:
+                throw new InvalidDnDOperationException();
+            }
+        }
+
+        private void dispatchEnterEvent(SunDropTargetEvent e) {
+            synchronized (peer) {
+
+                // store the drop action here to track operation changes
+                peer.previousDA = dropAction;
+
+                // setup peer context
+                peer.nativeDragContext = nativeCtxt;
+                peer.currentT          = formats;
+                peer.currentSA         = actions;
+                peer.currentDA         = dropAction;
+                // To allow data retrieval.
+                peer.dropStatus        = STATUS_ACCEPT;
+                peer.dropComplete      = false;
+
+                try {
+                    peer.processEnterMessage(e);
+                } finally {
+                    peer.dropStatus        = STATUS_NONE;
+                }
+
+                setReturnValue(peer.currentDA);
+            }
+        }
+
+        private void dispatchMotionEvent(SunDropTargetEvent e) {
+            synchronized (peer) {
+
+                boolean operationChanged = peer.previousDA != dropAction;
+                peer.previousDA = dropAction;
+
+                // setup peer context
+                peer.nativeDragContext = nativeCtxt;
+                peer.currentT          = formats;
+                peer.currentSA         = actions;
+                peer.currentDA         = dropAction;
+                // To allow data retrieval.
+                peer.dropStatus        = STATUS_ACCEPT;
+                peer.dropComplete      = false;
+
+                try {
+                    peer.processMotionMessage(e, operationChanged);
+                } finally {
+                    peer.dropStatus        = STATUS_NONE;
+                }
+
+                setReturnValue(peer.currentDA);
+            }
+        }
+
+        private void dispatchExitEvent(SunDropTargetEvent e) {
+            synchronized (peer) {
+
+                // setup peer context
+                peer.nativeDragContext = nativeCtxt;
+
+                peer.processExitMessage(e);
+            }
+        }
+
+        private void dispatchDropEvent(SunDropTargetEvent e) {
+            synchronized (peer) {
+
+                // setup peer context
+                peer.nativeDragContext = nativeCtxt;
+                peer.currentT          = formats;
+                peer.currentSA         = actions;
+                peer.currentDA         = dropAction;
+
+                peer.processDropMessage(e);
+            }
+        }
+
+        void setReturnValue(int ret) {
+            returnValue = ret;
+        }
+
+        int getReturnValue() {
+            return returnValue;
+        }
+
+        boolean isDone() {
+            return eventSet.isEmpty();
+        }
+
+        void registerEvent(SunDropTargetEvent e) {
+            handler.lock();
+            if (!eventSet.add(e) && dndLog.isLoggable(Level.FINE)) {
+                dndLog.log(Level.FINE, "Event is already registered: " + e);
+            }
+            handler.unlock();
+        }
+
+        void unregisterEvent(SunDropTargetEvent e) {
+            handler.lock();
+            try {
+                if (!eventSet.remove(e)) {
+                    // This event has already been unregistered.
+                    return;
+                }
+                if (eventSet.isEmpty()) {
+                    if (!dispatcherDone && dispatchType == DISPATCH_SYNC) {
+                        handler.exit();
+                    }
+                    dispatcherDone = true;
+                }
+            } finally {
+                handler.unlock();
+            }
+
+            try {
+                peer.eventProcessed(e, returnValue, dispatcherDone);
+            } finally {
+                /*
+                 * Clear the reference to the native context if all copies of
+                 * the original event are processed.
+                 */
+                if (dispatcherDone) {
+                    nativeCtxt = 0;
+                    // Fix for 6342381
+                    peer.nativeDragContext = 0;
+
+                }
+            }
+        }
+
+        public void unregisterAllEvents() {
+            Object[] events = null;
+            handler.lock();
+            try {
+                events = eventSet.toArray();
+            } finally {
+                handler.unlock();
+            }
+
+            if (events != null) {
+                for (int i = 0; i < events.length; i++) {
+                    unregisterEvent((SunDropTargetEvent)events[i]);
+                }
+            }
+        }
+    }
+}