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 */
46 public static void postRequest(Request req) {
47 lazyInitialize();
48 requestQueue.enqueue(req);
49 }
50
51 /**
52 * Process requests as they are queued.
53 */
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 */
78 public static synchronized void startProcessing() {
79 if (dispatcher == null) {
80 dispatcher = new Thread(null, new RequestProcessor(), "Request Processor", 0, false);
81 dispatcher.setPriority(Thread.NORM_PRIORITY + 2);
82 dispatcher.start();
83 }
84 }
85
86
87 /**
88 * This method performs lazy initialization.
89 */
90 private static synchronized void lazyInitialize() {
91 if (requestQueue == null) {
92 requestQueue = new Queue<Request>();
93 }
94 }
95
96 }
--- EOF ---