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    1   /*
    2    * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/util/TimeoutController.java,v 1.6 2004/04/18 23:51:38 jsdever Exp $
    3    * $Revision: 480424 $
    4    * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
    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: 480424 $
    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  }