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| 1 | +/* | |
| 2 | + * Copyright (c) 1997, 2002, 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 | + | |
| 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 | +} | |