1 /* 2 * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package sun.awt; 26 27 import java.awt.Component; 28 import java.awt.Rectangle; 29 import java.awt.event.PaintEvent; 30 31 /** 32 * PaintEventDispatcher is responsible for dispatching PaintEvents. There 33 * can be only one PaintEventDispatcher active at a particular time. 34 * 35 */ 36 public class PaintEventDispatcher { 37 /** 38 * Singleton dispatcher. 39 */ 40 private static PaintEventDispatcher dispatcher; 41 42 /** 43 * Sets the current <code>PaintEventDispatcher</code>. 44 * 45 * @param dispatcher PaintEventDispatcher 46 */ 47 public static void setPaintEventDispatcher( 48 PaintEventDispatcher dispatcher) { 49 synchronized(PaintEventDispatcher.class) { 50 PaintEventDispatcher.dispatcher = dispatcher; 51 } 52 } 53 54 /** 55 * Returns the currently active <code>PaintEventDispatcher</code>. This 56 * will never return null. 57 * 58 * @return PaintEventDispatcher 59 */ 60 public static PaintEventDispatcher getPaintEventDispatcher() { 61 synchronized(PaintEventDispatcher.class) { 62 if (dispatcher == null) { 63 dispatcher = new PaintEventDispatcher(); 64 } 65 return dispatcher; 66 } 67 } 68 69 /** 70 * Creates and returns the <code>PaintEvent</code> that should be 71 * dispatched for the specified component. If this returns null 72 * no <code>PaintEvent</code> is dispatched. 73 * <p> 74 * <b>WARNING:</b> This is invoked from the native thread, be careful 75 * what methods you end up invoking here. 76 */ 77 public PaintEvent createPaintEvent(Component target, int x, int y, int w, 78 int h) { 79 80 return new PaintEvent((Component)target, PaintEvent.PAINT, 81 new Rectangle(x, y, w, h)); 82 } 83 84 /** 85 * Returns true if a native background erase should be done for 86 * the specified Component. 87 */ 88 public boolean shouldDoNativeBackgroundErase(Component c) { 89 return true; 90 } 91 92 /** 93 * This method is invoked from the toolkit thread when the surface 94 * data of the component needs to be replaced. The method run() of 95 * the Runnable argument performs surface data replacing, run() 96 * should be invoked on the EDT of this component's AppContext. 97 * Returns true if the Runnable has been enqueued to be invoked 98 * on the EDT. 99 * (Fix 6255371.) 100 */ 101 public boolean queueSurfaceDataReplacing(Component c, Runnable r) { 102 return false; 103 } 104 }