Implementing a Process Timeout

I had a slightly unusual requirement to implement recently where I need to execute a command line process from Java + have it timeout if it didn't complete within a given timeframe.

Having considered a rather messy solution involving threads, joins, etc, I stumbled across the Executor framework that appeared in Java 1.5. Although the concepts seemed a little abstract at first, it provided a fairly elegant way of doing it:

public void executeCommand(String command, long timeoutInSeconds) throws IOException,
    InterruptedException, ProcessException {
  ExecutorService service = Executors.newSingleThreadExecutor();
  Process process = Runtime.getRuntime().exec(command);
  try {
    Callable call = new CallableProcess(process);
    Future future = service.submit(call);
    int exitValue = future.get(timeoutInSeconds, TimeUnit.SECONDS);
    if (exitValue != 0) {
      throw new ProcessException("Process did not exit correctly");
    }
  }
  catch (ExecutionException e) {
    throw new ProcessException("Process failed to execute", e);
  }
  catch (TimeoutException e) {
    process.destroy();
    throw new ProcessException("Process timed out", e);
  }
  finally {
    service.shutdown();
  }
}

private class CallableProcess implements Callable {

  private Process p;

  public CallableProcess(Process process) {
    p = process;
  }

  public Integer call() throws Exception {
    return p.waitFor();
  }
}

Best of all, it actually works. :-)