01: /*
02: * <copyright>
03: *
04: * Copyright 1997-2004 BBNT Solutions, LLC
05: * under sponsorship of the Defense Advanced Research Projects
06: * Agency (DARPA).
07: *
08: * You can redistribute this software and/or modify it under the
09: * terms of the Cougaar Open Source License as published on the
10: * Cougaar Open Source Website (www.cougaar.org).
11: *
12: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
13: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
14: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
15: * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
16: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
17: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
18: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
22: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: *
24: * </copyright>
25: */
26:
27: // Later this will move elsewhere...
28: package org.cougaar.core.thread;
29:
30: import org.cougaar.core.service.ThreadService;
31: import org.cougaar.util.CircularQueue;
32:
33: /**
34: * This utility class embads a {@link CircularQueue} in its
35: * own {@link Schedulable}, the body of which processes elements on the queue
36: * for up to 500ms or until the queue is empty, whichever comes
37: * first. Every addition to the queue (re)starts the Schedulable.
38: */
39: public class RunnableQueue implements Runnable {
40: private static final long MAX_RUNTIME = 500;
41: private final CircularQueue<Runnable> queue;
42: private final Schedulable sched;
43:
44: public RunnableQueue(ThreadService svc, String name) {
45: queue = new CircularQueue<Runnable>();
46: sched = svc.getThread(this , this , name);
47: }
48:
49: public void add(Runnable runnable) {
50: synchronized (queue) {
51: queue.add(runnable);
52: }
53: sched.start();
54: }
55:
56: public void run() {
57: long start = System.currentTimeMillis();
58: Runnable next = null;
59: boolean restart = false;
60: while (true) {
61: synchronized (queue) {
62: if (queue.isEmpty()) {
63: break;
64: }
65: if (System.currentTimeMillis() - start > MAX_RUNTIME) {
66: // Spent too long in this thread but the queue
67: // isn't empty yet. Start a new thread.
68: restart = true;
69: break;
70: }
71: next = queue.next();
72: }
73: next.run();
74: }
75: if (restart) {
76: sched.start();
77: }
78: }
79: }
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