1/* 2 * Copyright (c) 2000, 2001, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25package sun.jvm.hotspot.utilities; 26 27/** This class abstracts the notion of a worker thread which is fed 28 tasks in the form of Runnables. */ 29 30public class WorkerThread { 31 private volatile boolean done = false; 32 private MessageQueueBackend mqb; 33 private MessageQueue mq; 34 35 public WorkerThread() { 36 mqb = new MessageQueueBackend(); 37 mq = mqb.getFirstQueue(); 38 39 // Enable to terminate this worker during runnning by daemonize. 40 Thread mqthread = new Thread(new MainLoop()); 41 mqthread.setDaemon(true); 42 mqthread.start(); 43 } 44 45 /** Runs the given Runnable in the thread represented by this 46 WorkerThread object at an unspecified later time. */ 47 public void invokeLater(Runnable runnable) { 48 mq.writeMessage(runnable); 49 } 50 51 /** Can be used to dispose of the internal worker thread. Note that 52 this method may return before the internal worker thread 53 terminates. */ 54 public void shutdown() { 55 done = true; 56 mq.writeMessage(new Runnable() { public void run() {} }); 57 } 58 59 class MainLoop implements Runnable { 60 private MessageQueue myMq; 61 62 public MainLoop() { 63 myMq = mqb.getSecondQueue(); 64 } 65 66 public void run() { 67 while (!done) { 68 Runnable runnable = (Runnable) myMq.readMessage(); 69 try { 70 runnable.run(); 71 } catch (Exception e) { 72 e.printStackTrace(); 73 } 74 } 75 } 76 } 77} 78