/*

 * Copyright 2003-2008 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.X11;

import java.util.Iterator;

/**

 * This class is a registry for the supported drag and drop protocols.

 *

 * @since 1.5

 */

final class XDropTargetEventProcessor {

    private static final XDropTargetEventProcessor theInstance =

        new XDropTargetEventProcessor();

    private static boolean active = false;

    // The current drop protocol.

    private XDropTargetProtocol protocol = null;

    private XDropTargetEventProcessor() {}

    private boolean doProcessEvent(XEvent ev) {

        if (ev.get_type() == (int)XConstants.DestroyNotify &&

            protocol != null &&

            ev.get_xany().get_window() == protocol.getSourceWindow()) {

            protocol.cleanup();

            protocol = null;

            return false;

        }

        if (ev.get_type() == (int)XConstants.PropertyNotify) {

            XPropertyEvent xproperty = ev.get_xproperty();

            if (xproperty.get_atom() ==

                MotifDnDConstants.XA_MOTIF_DRAG_RECEIVER_INFO.getAtom()) {

                XDropTargetRegistry.getRegistry().updateEmbedderDropSite(xproperty.get_window());

            }

        }

        if (ev.get_type() != (int)XConstants.ClientMessage) {

            return false;

        }

        boolean processed = false;

        XClientMessageEvent xclient = ev.get_xclient();

        XDropTargetProtocol curProtocol = protocol;

        if (protocol != null) {

            if (protocol.getMessageType(xclient) !=

                XDropTargetProtocol.UNKNOWN_MESSAGE) {

                processed = protocol.processClientMessage(xclient);

            } else {

                protocol = null;

            }

        }

        if (protocol == null) {

            Iterator dropTargetProtocols =

                XDragAndDropProtocols.getDropTargetProtocols();

            while (dropTargetProtocols.hasNext()) {

                XDropTargetProtocol dropTargetProtocol =

                    (XDropTargetProtocol)dropTargetProtocols.next();

                // Don't try to process it again with the current protocol.

                if (dropTargetProtocol == curProtocol) {

                    continue;

                }

                if (dropTargetProtocol.getMessageType(xclient) ==

                    XDropTargetProtocol.UNKNOWN_MESSAGE) {

                    continue;

                }

                protocol = dropTargetProtocol;

                processed = protocol.processClientMessage(xclient);

                break;

            }

        }

        return processed;

    }

    static void reset() {

        theInstance.protocol = null;

    }

    static void activate() {

        active = true;

    }

    // Fix for 4915454 - do not call doProcessEvent() until the first drop

    // target is registered to avoid premature loading of DnD protocol

    // classes.

    static boolean processEvent(XEvent ev) {

        return active ? theInstance.doProcessEvent(ev) : false;

    }

}