Package ae.sun.awt

Source Code of ae.sun.awt.PaintEventDispatcher

/*
* Copyright 2005 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 ae.sun.awt;

import ae.java.awt.Component;
import ae.java.awt.Rectangle;
import ae.java.awt.event.PaintEvent;

/**
* PaintEventDispatcher is responsible for dispatching PaintEvents.  There
* can be only one PaintEventDispatcher active at a particular time.
*
*/
public class PaintEventDispatcher {
    /**
     * Singleton dispatcher.
     */
    private static PaintEventDispatcher dispatcher;

    /**
     * Sets the current <code>PaintEventDispatcher</code>.
     *
     * @param dispatcher PaintEventDispatcher
     */
    public static void setPaintEventDispatcher(
                          PaintEventDispatcher dispatcher) {
        synchronized(PaintEventDispatcher.class) {
            PaintEventDispatcher.dispatcher = dispatcher;
        }
    }

    /**
     * Returns the currently active <code>PaintEventDispatcher</code>.  This
     * will never return null.
     *
     * @return PaintEventDispatcher
     */
    public static PaintEventDispatcher getPaintEventDispatcher() {
        synchronized(PaintEventDispatcher.class) {
            if (dispatcher == null) {
                dispatcher = new PaintEventDispatcher();
            }
            return dispatcher;
        }
    }

    /**
     * Creates and returns the <code>PaintEvent</code> that should be
     * dispatched for the specified component.  If this returns null
     * no <code>PaintEvent</code> is dispatched.
     * <p>
     * <b>WARNING:</b> This is invoked from the native thread, be careful
     * what methods you end up invoking here.
     */
    public PaintEvent createPaintEvent(Component target, int x, int y, int w,
                                       int h) {

        return new PaintEvent((Component)target, PaintEvent.PAINT,
                              new Rectangle(x, y, w, h));
    }

    /**
     * Returns true if a native background erase should be done for
     * the specified Component.
     */
    public boolean shouldDoNativeBackgroundErase(Component c) {
        return true;
    }

    /**
     * This method is invoked from the toolkit thread when the surface
     * data of the component needs to be replaced. The method run() of
     * the Runnable argument performs surface data replacing, run()
     * should be invoked on the EDT of this component's AppContext.
     * Returns true if the Runnable has been enqueued to be invoked
     * on the EDT.
     * (Fix 6255371.)
     */
    public boolean queueSurfaceDataReplacing(Component c, Runnable r) {
        return false;
    }
}
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