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()} method will be called when the event 32 * is dispatched, using the {@code EventDispatchThread}. 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} 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} 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 }