BooleanLastTrueTracker.java

package freenet.support;

/** Tracks when a condition was last true, e.g. whether a peer is connected. Self-synchronized. */
public class BooleanLastTrueTracker {
	
	private boolean isTrue;
	private long timeLastTrue;
	
	public BooleanLastTrueTracker() {
		isTrue = false;
		timeLastTrue = -1;
	}

	/** Initialise with a time last connected */
	public BooleanLastTrueTracker(long lastTrue) {
		isTrue = false;
		timeLastTrue = lastTrue;
	}

	public synchronized boolean isTrue() {
		return isTrue;
	}
	
	public synchronized boolean set(boolean value, long now) {
		if(value == isTrue) return value;
		if(!isTrue)
			timeLastTrue = now;
		isTrue = value;
		return !value;
	}
	
	public synchronized long getTimeLastTrue(long now) {
		if(isTrue) return now;
		else return timeLastTrue;
	}

}