001 /*
002 * $RCSfile: Task.java,v $
003 *
004 * Created on September 30, 2002, 10:02 AM
005 *
006 * This file is part of the STAR Scheduler.
007 * Copyright (c) 2002-2006 STAR Collaboration - Brookhaven National Laboratory
008 *
009 * STAR Scheduler is free software; you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation; either version 2 of the License, or
012 * (at your option) any later version.
013 *
014 * STAR Scheduler is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with STAR Scheduler; if not, write to the Free Software
021 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
022 */
023 package gov.bnl.star.offline.scheduler.util;
024
025
026 /** A task that is going to be executed in a separate thread while displaying a
027 * character every second on the standard output.
028 *
029 * @author Gabriele Carcassi
030 * @version $Revision: 1.9 $ $Date: 2006/11/21 00:41:29 $
031 */
032 public class Task extends Thread {
033 private char waitingDot;
034 private int msPause = 1000;
035 private int msTimeout;
036
037 /** The exit status of the process. */
038 protected int exitStatus;
039
040 /** A new task to be executed in background. The character displayed while waiting
041 * will be a '.'
042 */
043 public Task() {
044 this('.', 0);
045 }
046
047 /** A new task to be executed in background. The character displayed while waiting
048 * will be the one specified
049 * @param waitingDot character to display every second while waiting for the task to finish
050 */
051 public Task(char waitingDot) {
052 this(waitingDot, 0);
053 }
054
055 /** A new task to be executed in background with a timeout. If after the timeout the
056 * task hasn't finished it will be considered as failed.
057 * @param msTimeout timeout in milliseconds
058 */
059 public Task(int msTimeout) {
060 this('.', msTimeout);
061 }
062
063 /** A new task to be executed in background with a timeout. The character displayed
064 * while waiting will be the one specified. If after the timeout the task hasn't
065 * finished it will be considered as failed. The
066 * @param waitingDot character to display every second while waiting for the task to finish
067 * @param msTimeout timeout in milliseconds
068 */
069 public Task(char waitingDot, int msTimeout) {
070 this.waitingDot = waitingDot;
071 this.msTimeout = msTimeout;
072 }
073
074 /** Returns the condition on which the task finished. Return value 0 means no errors.
075 * @return for success 0, else for failure
076 */
077 public int getExitStatus() {
078 return exitStatus;
079 }
080
081 /** Starts the task and wait for the result. While waiting, some dots are displayed
082 * to give the user the impression that the job didn't hang.
083 */
084 public void execute() {
085 start();
086
087 long startTime = System.currentTimeMillis();
088
089 while (isAlive()) {
090 try {
091 Thread.sleep(msPause);
092
093 if (isAlive()) {
094 System.out.print(waitingDot);
095 }
096
097 long elapsedTime = System.currentTimeMillis() - startTime;
098
099 if ((msTimeout > 0) && (elapsedTime > msTimeout)) {
100 this.destroy();
101 }
102 } catch (Exception e) {
103 throw new RuntimeException("Thread was interrupted");
104 }
105 }
106 }
107 }