donaldp 01/12/22 16:11:08
Added: proposal/myrmidon/src/java/org/apache/myrmidon/framework/exec
ExecuteWatchdog.java
Log:
Move WatchDog class to myrmidon framework section.
Revision Changes Path
1.1
jakarta-ant/proposal/myrmidon/src/java/org/apache/myrmidon/framework/exec/ExecuteWatchdog.java
Index: ExecuteWatchdog.java
===================================================================
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE file.
*/
package org.apache.myrmidon.framework.exec;
import org.apache.myrmidon.api.TaskException;
/**
* Destroys a process running for too long. For example: <pre>
* ExecuteWatchdog watchdog = new ExecuteWatchdog(30000);
* Execute exec = new Execute(myloghandler, watchdog);
* exec.setCommandLine(mycmdline);
* int exitvalue = exec.execute();
* if (exitvalue != SUCCESS && watchdog.killedProcess()){
* // it was killed on purpose by the watchdog
* }
* </pre>
*
* @author [EMAIL PROTECTED]
* @author <a href="mailto:[EMAIL PROTECTED]">Stephane Bailliez</a>
* @see Execute
*/
public class ExecuteWatchdog
implements Runnable
{
/**
* say whether or not the watchog is currently monitoring a process
*/
private boolean m_watch;
/**
* exception that might be thrown during the process execution
*/
private Exception m_caught;
/**
* say whether or not the process was killed due to running overtime
*/
private boolean m_killedProcess;
/**
* the process to execute and watch for duration
*/
private Process m_process;
/**
* timeout duration. Once the process running time exceeds this it should
be
* killed
*/
private int m_timeout;
/**
* Creates a new watchdog with a given timeout.
*
* @param timeout the timeout for the process in milliseconds. It must be
* greather than 0.
*/
public ExecuteWatchdog( int timeout )
{
if( timeout < 1 )
{
throw new IllegalArgumentException( "timeout lesser than 1." );
}
m_timeout = timeout;
}
/**
* Indicates whether or not the watchdog is still monitoring the process.
*
* @return <tt>true</tt> if the process is still running, otherwise <tt>
* false</tt> .
*/
public boolean isWatching()
{
return m_watch;
}
/**
* This method will rethrow the exception that was possibly caught during
* the run of the process. It will only remains valid once the process has
* been terminated either by 'error', timeout or manual intervention.
* Information will be discarded once a new process is ran.
*
* @throws TaskException a wrapped exception over the one that was
silently
* swallowed and stored during the process run.
*/
public void checkException()
throws TaskException
{
if( m_caught != null )
{
throw new TaskException( "Exception in ExecuteWatchdog.run: "
+ m_caught.getMessage(), m_caught );
}
}
/**
* Indicates whether the last process run was killed on timeout or not.
*
* @return <tt>true</tt> if the process was killed otherwise
<tt>false</tt>
* .
*/
public boolean killedProcess()
{
return m_killedProcess;
}
/**
* Watches the process and terminates it, if it runs for to long.
*/
public synchronized void run()
{
try
{
// This isn't a Task, don't have a Project object to log.
// project.log("ExecuteWatchdog: timeout = "+timeout+" msec",
Project.MSG_VERBOSE);
final long until = System.currentTimeMillis() + m_timeout;
long now;
while( m_watch && until > ( now = System.currentTimeMillis() ) )
{
try
{
wait( until - now );
}
catch( InterruptedException e )
{
}
}
// if we are here, either someone stopped the watchdog,
// we are on timeout and the process must be killed, or
// we are on timeout and the process has already stopped.
try
{
// We must check if the process was not stopped
// before being here
m_process.exitValue();
}
catch( IllegalThreadStateException e )
{
// the process is not terminated, if this is really
// a timeout and not a manual stop then kill it.
if( m_watch )
{
m_killedProcess = true;
m_process.destroy();
}
}
}
catch( Exception e )
{
m_caught = e;
}
finally
{
cleanUp();
}
}
/**
* Watches the given process and terminates it, if it runs for too long.
All
* information from the previous run are reset.
*
* @param process the process to monitor. It cannot be <tt>null</tt>
* @throws IllegalStateException thrown if a process is still being
* monitored.
*/
public synchronized void start( Process process )
{
if( process == null )
{
throw new NullPointerException( "process is null." );
}
if( m_process != null )
{
throw new IllegalStateException( "Already running." );
}
m_caught = null;
m_killedProcess = false;
m_watch = true;
m_process = process;
final Thread thread = new Thread( this, "WATCHDOG" );
thread.setDaemon( true );
thread.start();
}
/**
* Stops the watcher. It will notify all threads possibly waiting on this
* object.
*/
public synchronized void stop()
{
m_watch = false;
notifyAll();
}
/**
* reset the monitor flag and the process.
*/
protected void cleanUp()
{
m_watch = false;
m_process = null;
}
}
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