X11DropTargetContextPeer.java

/*
 * Copyright 2003-2004 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.motif;

import java.awt.Component;
import java.awt.peer.ComponentPeer;

import sun.awt.AppContext;
import sun.awt.SunToolkit;

import sun.awt.dnd.SunDropTargetContextPeer;
import sun.awt.dnd.SunDropTargetEvent;

/**
 * The X11DropTargetContextPeer class is the class responsible for handling
 * the interaction between the XDnD/Motif DnD subsystem and Java drop targets.
 *
 * @since 1.5
 */
final class X11DropTargetContextPeer extends SunDropTargetContextPeer {

    /*
     * A key to store a peer instance for an AppContext.
     */
    private static final Object DTCP_KEY = "DropTargetContextPeer";

    private X11DropTargetContextPeer() {}

    public static X11DropTargetContextPeer getPeer(AppContext appContext) {
        synchronized (_globalLock) {
            X11DropTargetContextPeer peer =
                (X11DropTargetContextPeer)appContext.get(DTCP_KEY);
            if (peer == null) {
                peer = new X11DropTargetContextPeer();
                appContext.put(DTCP_KEY, peer);
            }

            return peer;
        }
    }

    /*
     * Note:
     * the method can be called on the toolkit thread while holding AWT_LOCK.
     */
    private static void postDropTargetEventToPeer(final Component component,
                                                  final int x, final int y,
                                                  final int dropAction,
                                                  final int actions,
                                                  final long[] formats,
                                                  final long nativeCtxt,
                                                  final int eventID) {

        AppContext appContext = SunToolkit.targetToAppContext(component);
        X11DropTargetContextPeer peer = getPeer(appContext);

        peer.postDropTargetEvent(component, x, y, dropAction, actions, formats,
                                 nativeCtxt, eventID,
                                 !SunDropTargetContextPeer.DISPATCH_SYNC);
    }

    protected void eventProcessed(SunDropTargetEvent e, int returnValue,
                                  boolean dispatcherDone) {
        /* If the event was not consumed, send a response to the source. */
        long ctxt = getNativeDragContext();
        if (ctxt != 0) {
            sendResponse(e.getID(), returnValue, ctxt, dispatcherDone,
                         e.isConsumed());
        }
    }

    protected void doDropDone(boolean success, int dropAction,
                              boolean isLocal) {
        dropDone(getNativeDragContext(), success, dropAction);
    }

    protected Object getNativeData(long format) {
        return getData(getNativeDragContext(), format);
    }

    protected void processEnterMessage(SunDropTargetEvent event) {
        if (!processSunDropTargetEvent(event)) {
            super.processEnterMessage(event);
        }
    }

    protected void processExitMessage(SunDropTargetEvent event) {
        if (!processSunDropTargetEvent(event)) {
            super.processExitMessage(event);
        }
    }

    protected void processMotionMessage(SunDropTargetEvent event,
                                        boolean operationChanged) {
        if (!processSunDropTargetEvent(event)) {
            super.processMotionMessage(event, operationChanged);
        }
    }

    protected void processDropMessage(SunDropTargetEvent event) {
        if (!processSunDropTargetEvent(event)) {
            super.processDropMessage(event);
        }
    }

    // If source is an XEmbedCanvasPeer, passes the event to it for processing and
    // return true if the event is forwarded to the XEmbed child.
    // Otherwise, does nothing and return false.
    private boolean processSunDropTargetEvent(SunDropTargetEvent event) {
        Object source = event.getSource();

        if (source instanceof Component) {
            ComponentPeer peer = ((Component)source).getPeer();
            if (peer instanceof MEmbedCanvasPeer) {
                MEmbedCanvasPeer mEmbedCanvasPeer = (MEmbedCanvasPeer)peer;
                /* The native context is the pointer to the XClientMessageEvent
                   structure. */
                long ctxt = getNativeDragContext();

                /* If the event is not consumed, pass it to the
                   MEmbedCanvasPeer for processing. */
                if (!event.isConsumed()) {
                    // NOTE: ctxt can be zero at this point.
                    if (mEmbedCanvasPeer.processXEmbedDnDEvent(ctxt,
                                                               event.getID())) {
                        event.consume();
                        return true;
                    }
                }
            }
        }

        return false;
    }

    private native void sendResponse(int eventID, int returnValue,
                                     long nativeCtxt, boolean dispatcherDone,
                                     boolean consumed);

    private native void dropDone(long nativeCtxt, boolean success,
                                 int dropAction);

    private native Object getData(long nativeCtxt, long format);
}