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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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.
 *
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package sun.awt;

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

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

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

    
Returns the currently active PaintEventDispatcher. This will never return null. 
Returns:
PaintEventDispatcher/**
     * Returns the currently active {@code PaintEventDispatcher}.  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 PaintEvent that should be dispatched for the specified component. If this returns null no PaintEvent is dispatched. 

WARNING: This is invoked from the native thread, be careful
what methods you end up invoking here.
/**
     * Creates and returns the {@code PaintEvent} that should be
     * dispatched for the specified component.  If this returns null
     * no {@code PaintEvent} 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(target, PaintEvent.PAINT,
                              new Rectangle(x, y, w, h));
    }

    
Returns true if a native background erase should be done for
the specified Component.
/**
     * 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.)
/**
     * 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;
    }
}