genericfsm.java

来自「real-time design patterns in Real-time j」· Java 代码 · 共 82 行

package designPatterns.Fsm;


import javax.realtime.AsyncEventHandler;
import javax.realtime.OneShotTimer;
import javax.realtime.RelativeTime;


import rtEnv.RtConstants;
import utils.Semaphore;

public abstract class GenericFsm {

	private OneShotTimer fsmTimer;
	private RelativeTime fsmTimeout;
	private Semaphore readySem;

	public GenericFsm(long initTimeout) {

		readySem = new Semaphore();

		/*
		 * Set up the timer
		 */
		// First create AsyncEventHandler for the timer
		AsyncEventHandler timerHndlr = new AsyncEventHandler() {
			public void handleAsyncEvent() {
				timerExpired();
			}
		};

		// Create the timer
		fsmTimeout = new RelativeTime(initTimeout, RtConstants.ZERO_NANOS);
		fsmTimer = new OneShotTimer(fsmTimeout, timerHndlr);
	}

	// Current state
	protected GenericFsmState state;

	public synchronized void setState(GenericFsmState newState) {
		state.exitAction(this);
		state = newState;
		state.entryAction(this);
	}

	public abstract void illegalTrigger();

	
	/*
	 * Timer-handling methods
	 */
	public void startTimer(long timeout) {
		stopTimer();
		fsmTimeout.set(timeout);
		fsmTimer.reschedule(fsmTimeout);
		fsmTimer.start();
	}
	public void stopTimer() {
		if (fsmTimer.isRunning()) {
			fsmTimer.stop();
		}
	}
	public boolean isTimerActive() {
		return fsmTimer.isRunning();
	}	

	public void timerExpired() {
		stopTimer();
		state.timerExpired(this);
	}
	
	public void initCompleted() {
		readySem.up();
	}

	public void waitForInit() {
		readySem.down();
	}

	
}