| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2002 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.awt; |
| 27 | |
| 28 | /** |
| 29 | * An interface for events that know how to dispatch themselves. |
| 30 | * By implementing this interface an event can be placed upon the event |
| 31 | * queue and its <code>dispatch()</code> method will be called when the event |
| 32 | * is dispatched, using the <code>EventDispatchThread</code>. |
| 33 | * <p> |
| 34 | * This is a very useful mechanism for avoiding deadlocks. If |
| 35 | * a thread is executing in a critical section (i.e., it has entered |
| 36 | * one or more monitors), calling other synchronized code may |
| 37 | * cause deadlocks. To avoid the potential deadlocks, an |
| 38 | * <code>ActiveEvent</code> can be created to run the second section of |
| 39 | * code at later time. If there is contention on the monitor, |
| 40 | * the second thread will simply block until the first thread |
| 41 | * has finished its work and exited its monitors. |
| 42 | * <p> |
| 43 | * For security reasons, it is often desirable to use an <code>ActiveEvent</code> |
| 44 | * to avoid calling untrusted code from a critical thread. For |
| 45 | * instance, peer implementations can use this facility to avoid |
| 46 | * making calls into user code from a system thread. Doing so avoids |
| 47 | * potential deadlocks and denial-of-service attacks. |
| 48 | * |
| 49 | * @author Timothy Prinzing |
| 50 | * @since 1.2 |
| 51 | */ |
| 52 | public interface ActiveEvent { |
| 53 | |
| 54 | /** |
| 55 | * Dispatch the event to its target, listeners of the events source, |
| 56 | * or do whatever it is this event is supposed to do. |
| 57 | */ |
| 58 | public void dispatch(); |
| 59 | } |