package net.sourceforge.fenixedu.util.kerberos;

import org.apache.tools.ant.util.TimeoutObserver;
import org.apache.tools.ant.util.Watchdog;

public class ScriptWatchDog implements TimeoutObserver {

	private Watchdog watchdog;
	private Process process;
	
	private boolean watch;
	private boolean killedProcess;
	private Exception exception;
	
	public ScriptWatchDog(long timeOut) {
		watchdog = new Watchdog(timeOut);
		watchdog.addTimeoutObserver(this);
		
	}
	
	public void start(Process process) {
		if(process == null) {
			throw new NullPointerException("no process defined");
		}
		if(this.process != null) {
			throw new IllegalStateException("process already defined");
		}
		this.process = process;
		exception = null;
		watch = true;
		killedProcess = false;
		watchdog.start();
	}
	
	public void stop() {
        watchdog.stop();
        watch = false;
        process = null;
	}
	
	public void timeoutOccured(Watchdog w) {
		try {
			try {
				process.exitValue();
			}catch(IllegalThreadStateException e) {
				if(watch) {
					process.destroy();
					killedProcess = true;
				}
			}
		}catch(Exception e) {
			exception = e;
		}finally {
			cleanUp();
		}

	}
	
	protected void cleanUp() {
		watch = false;
		process = null;
	}

	public boolean isWatching() {
		return watch;
	}
	
	public boolean killedProcess() {
		return killedProcess;
	}
	
	public Exception getException() {
		return exception;
	}

}