1 | /*
|
---|
2 | * Copyright 2002-2005 The Apache Software Foundation
|
---|
3 | *
|
---|
4 | * Licensed under the Apache License, Version 2.0 (the "License");
|
---|
5 | * you may not use this file except in compliance with the License.
|
---|
6 | * You may obtain a copy of the License at
|
---|
7 | *
|
---|
8 | * http://www.apache.org/licenses/LICENSE-2.0
|
---|
9 | *
|
---|
10 | * Unless required by applicable law or agreed to in writing, software
|
---|
11 | * distributed under the License is distributed on an "AS IS" BASIS,
|
---|
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
---|
13 | * See the License for the specific language governing permissions and
|
---|
14 | * limitations under the License.
|
---|
15 | *
|
---|
16 | */
|
---|
17 |
|
---|
18 | package org.apache.tools.ant.util;
|
---|
19 |
|
---|
20 | import java.util.Enumeration;
|
---|
21 | import java.util.Vector;
|
---|
22 |
|
---|
23 | /**
|
---|
24 | * Generalization of <code>ExecuteWatchdog</code>
|
---|
25 | *
|
---|
26 | * @since Ant 1.5
|
---|
27 | *
|
---|
28 | * @see org.apache.tools.ant.taskdefs.ExecuteWatchdog
|
---|
29 | *
|
---|
30 | */
|
---|
31 | public class Watchdog implements Runnable {
|
---|
32 |
|
---|
33 | private Vector observers = new Vector(1);
|
---|
34 | private long timeout = -1;
|
---|
35 | private boolean stopped = false;
|
---|
36 |
|
---|
37 | /**
|
---|
38 | * Constructor for Watchdog.
|
---|
39 | * @param timeout the timeout to use in milliseconds (must be >= 1).
|
---|
40 | */
|
---|
41 | public Watchdog(long timeout) {
|
---|
42 | if (timeout < 1) {
|
---|
43 | throw new IllegalArgumentException("timeout less than 1.");
|
---|
44 | }
|
---|
45 | this.timeout = timeout;
|
---|
46 | }
|
---|
47 |
|
---|
48 | /**
|
---|
49 | * Add a timeout observer.
|
---|
50 | * @param to the timeout observer to add.
|
---|
51 | */
|
---|
52 | public void addTimeoutObserver(TimeoutObserver to) {
|
---|
53 | observers.addElement(to);
|
---|
54 | }
|
---|
55 |
|
---|
56 | /**
|
---|
57 | * Remove a timeout observer.
|
---|
58 | * @param to the timeout observer to remove.
|
---|
59 | */
|
---|
60 | public void removeTimeoutObserver(TimeoutObserver to) {
|
---|
61 | observers.removeElement(to);
|
---|
62 | }
|
---|
63 |
|
---|
64 | /**
|
---|
65 | * Inform the observers that a timeout has occured.
|
---|
66 | */
|
---|
67 | protected final void fireTimeoutOccured() {
|
---|
68 | Enumeration e = observers.elements();
|
---|
69 | while (e.hasMoreElements()) {
|
---|
70 | ((TimeoutObserver) e.nextElement()).timeoutOccured(this);
|
---|
71 | }
|
---|
72 | }
|
---|
73 |
|
---|
74 | /**
|
---|
75 | * Start the watch dog.
|
---|
76 | */
|
---|
77 | public synchronized void start() {
|
---|
78 | stopped = false;
|
---|
79 | Thread t = new Thread(this, "WATCHDOG");
|
---|
80 | t.setDaemon(true);
|
---|
81 | t.start();
|
---|
82 | }
|
---|
83 |
|
---|
84 | /**
|
---|
85 | * Stop the watch dog.
|
---|
86 | */
|
---|
87 | public synchronized void stop() {
|
---|
88 | stopped = true;
|
---|
89 | notifyAll();
|
---|
90 | }
|
---|
91 |
|
---|
92 | /**
|
---|
93 | * The run method of the watch dog thread.
|
---|
94 | * This simply does a wait for the timeout time, and
|
---|
95 | * if the stop flag has not been set when the wait has returned or
|
---|
96 | * has been interrupted, the watch dog listeners are informed.
|
---|
97 | */
|
---|
98 | public synchronized void run() {
|
---|
99 | final long until = System.currentTimeMillis() + timeout;
|
---|
100 | long now;
|
---|
101 | while (!stopped && until > (now = System.currentTimeMillis())) {
|
---|
102 | try {
|
---|
103 | wait(until - now);
|
---|
104 | } catch (InterruptedException e) {
|
---|
105 | // Ignore exception
|
---|
106 | }
|
---|
107 | }
|
---|
108 | if (!stopped) {
|
---|
109 | fireTimeoutOccured();
|
---|
110 | }
|
---|
111 | }
|
---|
112 |
|
---|
113 | }
|
---|