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1   /*
2    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/oac.hc3x/trunk/src/java/org/apache/commons/httpclient/util/TimeoutController.java $
3    * $Revision: 1425331 $
4    * $Date: 2012-12-22 19:29:41 +0100 (Sat, 22 Dec 2012) $
5    *
6    * ====================================================================
7    *
8    *  Licensed to the Apache Software Foundation (ASF) under one or more
9    *  contributor license agreements.  See the NOTICE file distributed with
10   *  this work for additional information regarding copyright ownership.
11   *  The ASF licenses this file to You under the Apache License, Version 2.0
12   *  (the "License"); you may not use this file except in compliance with
13   *  the License.  You may obtain a copy of the License at
14   *
15   *      http://www.apache.org/licenses/LICENSE-2.0
16   *
17   *  Unless required by applicable law or agreed to in writing, software
18   *  distributed under the License is distributed on an "AS IS" BASIS,
19   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20   *  See the License for the specific language governing permissions and
21   *  limitations under the License.
22   * ====================================================================
23   *
24   * This software consists of voluntary contributions made by many
25   * individuals on behalf of the Apache Software Foundation.  For more
26   * information on the Apache Software Foundation, please see
27   * <http://www.apache.org/>.
28   *
29   */
30  
31  package org.apache.commons.httpclient.util;
32  
33  /***
34   * <p>
35   * Executes a task with a specified timeout.
36   * </p>
37   * @author Ortwin Glueck
38   * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
39   * @version $Revision: 1425331 $
40   * @since 2.0
41   */
42  public final class TimeoutController {
43  
44      /***
45       * Do not instantiate objects of this class. Methods are static.
46       */
47      private TimeoutController() {
48      }
49  
50      /***
51       * Executes <code>task</code>. Waits for <code>timeout</code>
52       * milliseconds for the task to end and returns. If the task does not return
53       * in time, the thread is interrupted and an Exception is thrown.
54       * The caller should override the Thread.interrupt() method to something that
55       * quickly makes the thread die or use Thread.isInterrupted().
56       * @param task The thread to execute
57       * @param timeout The timeout in milliseconds. 0 means to wait forever.
58       * @throws TimeoutException if the timeout passes and the thread does not return.
59       */
60      public static void execute(Thread task, long timeout) throws TimeoutException {
61          task.start();
62          try {
63              task.join(timeout);
64          } catch (InterruptedException e) {
65              /* if somebody interrupts us he knows what he is doing */
66          }
67          if (task.isAlive()) {
68              task.interrupt();
69              throw new TimeoutException();
70          }
71      }
72  
73      /***
74       * Executes <code>task</code> in a new deamon Thread and waits for the timeout.
75       * @param task The task to execute
76       * @param timeout The timeout in milliseconds. 0 means to wait forever.
77       * @throws TimeoutException if the timeout passes and the thread does not return.
78       */
79      public static void execute(Runnable task, long timeout) throws TimeoutException {
80          Thread t = new Thread(task, "Timeout guard");
81          t.setDaemon(true);
82          execute(t, timeout);
83      }
84  
85      /***
86       * Signals that the task timed out.
87       */
88      public static class TimeoutException extends Exception {
89          /*** Create an instance */
90          public TimeoutException() {
91          }
92      }
93  }