java native Process timeout

Question

At the moment I execute a native process using the following:

java.lang.Process process = Runtime.getRuntime().exec(command); 
int returnCode = process.waitFor();

Suppose instead of waiting for the program to return I wish to terminate if a certain amount of time has elapsed. How do I do this?

Answer 1

This is how the Plexus CommandlineUtils does it:

Process p;

p = cl.execute();

...

if ( timeoutInSeconds <= 0 )
{
    returnValue = p.waitFor();
}
else
{
    long now = System.currentTimeMillis();
    long timeoutInMillis = 1000L * timeoutInSeconds;
    long finish = now + timeoutInMillis;
    while ( isAlive( p ) && ( System.currentTimeMillis() < finish ) )
    {
        Thread.sleep( 10 );
    }
    if ( isAlive( p ) )
    {
        throw new InterruptedException( "Process timeout out after " + timeoutInSeconds + " seconds" );
    }
    returnValue = p.exitValue();
}

public static boolean isAlive( Process p ) {
    try
    {
        p.exitValue();
        return false;
    } catch (IllegalThreadStateException e) {
        return true;
    }
}

Answer 2

You'd need a 2. thread that interrupts the thread that calls .waitFor(); Some non trivial synchronization will be needed to make it robust, but the basics are:

TimeoutThread:

 Thread.sleep(timeout);
 processThread.interrupt();

ProcessThread:

  try {
      proc.waitFor(); 
    } catch (InterruptedException e) {
       proc.destroy();
    }

Answer 3

All other responses are correct but it can be made more robust and efficient using FutureTask.

For example,

private static final ExecutorService THREAD_POOL 
    = Executors.newCachedThreadPool();

private static <T> T timedCall(Callable<T> c, long timeout, TimeUnit timeUnit)
    throws InterruptedException, ExecutionException, TimeoutException
{
    FutureTask<T> task = new FutureTask<T>(c);
    THREAD_POOL.execute(task);
    return task.get(timeout, timeUnit);
}

try {
    int returnCode = timedCall(new Callable<int>() {
        public int call() throws Exception
        {
            java.lang.Process process = Runtime.getRuntime().exec(command); 
            return process.waitFor();
        }, timeout, TimeUnit.SECONDS);
} catch (TimeoutException e) {
    // Handle timeout here
}

If you do this repeatedly, the thread pool is more efficient because it caches the threads.

Answer 4

What about the Groovy way

public void yourMethod() {
    ...
    Process process = new ProcessBuilder(...).start(); 
    //wait 5 secs or kill the process
    waitForOrKill(process, TimeUnit.SECONDS.toMillis(5));
    ...
}

public static void waitForOrKill(Process self, long numberOfMillis) {
    ProcessRunner runnable = new ProcessRunner(self);
    Thread thread = new Thread(runnable);
    thread.start();
    runnable.waitForOrKill(numberOfMillis);
}

protected static class ProcessRunner implements Runnable {
    Process process;
    private boolean finished;

    public ProcessRunner(Process process) {
        this.process = process;
    }

    public void run() {
        try {
            process.waitFor();
        } catch (InterruptedException e) {
            // Ignore
        }
        synchronized (this) {
            notifyAll();
            finished = true;
        }
    }

    public synchronized void waitForOrKill(long millis) {
        if (!finished) {
            try {
                wait(millis);
            } catch (InterruptedException e) {
                // Ignore
            }
            if (!finished) {
                process.destroy();
            }
        }
    }
}

Answer 5

just modified a bit according to my requirement. time out is 10 seconds here. process is getting destroyed after 10 seconds if it is not exiting.

public static void main(String arg[])

{

try{

Process p =Runtime.getRuntime().exec("\"C:/Program Files/VanDyke Software/SecureCRT/SecureCRT.exe\"");
long now = System.currentTimeMillis(); 
long timeoutInMillis = 1000L * 10; 
long finish = now + timeoutInMillis; 
while ( isAlive( p ) )
{ 
    Thread.sleep( 10 ); 
    if ( System.currentTimeMillis() > finish ) {

        p.destroy();

    }



} 

}
catch (Exception err) {
  err.printStackTrace();

    }

}

public static boolean isAlive( Process p ) {
try
{
p.exitValue();
return false;
} catch (IllegalThreadStateException e) {
return true;
}
}