1 /* 2 * Copyright (c) 1996, 2011, 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 sun.misc; 27 28 /** 29 * The request processor allows functors (Request instances) to be created 30 * in arbitrary threads, and to be posted for execution in a non-restricted 31 * thread. 32 * 33 * @author Steven B. Byrne 34 */ 35 36 37 public class RequestProcessor implements Runnable { 38 39 private static Queue<Request> requestQueue; 40 private static Thread dispatcher; 41 42 /** 43 * Queues a Request instance for execution by the request procesor 44 * thread. 45 */ postRequest(Request req)46 public static void postRequest(Request req) { 47 lazyInitialize(); 48 requestQueue.enqueue(req); 49 } 50 51 /** 52 * Process requests as they are queued. 53 */ run()54 public void run() { 55 lazyInitialize(); 56 while (true) { 57 try { 58 Request req = requestQueue.dequeue(); 59 try { 60 req.execute(); 61 } catch (Throwable t) { 62 // do nothing at the moment...maybe report an error 63 // in the future 64 } 65 } catch (InterruptedException e) { 66 // do nothing at the present time. 67 } 68 } 69 } 70 71 72 /** 73 * This method initiates the request processor thread. It is safe 74 * to call it after the thread has been started. It provides a way for 75 * clients to deliberately control the context in which the request 76 * processor thread is created 77 */ startProcessing()78 public static synchronized void startProcessing() { 79 if (dispatcher == null) { 80 dispatcher = new Thread(new RequestProcessor(), "Request Processor"); 81 dispatcher.setPriority(Thread.NORM_PRIORITY + 2); 82 dispatcher.start(); 83 } 84 } 85 86 87 /** 88 * This method performs lazy initialization. 89 */ lazyInitialize()90 private static synchronized void lazyInitialize() { 91 if (requestQueue == null) { 92 requestQueue = new Queue<Request>(); 93 } 94 } 95 96 } 97