Timer service

import java.lang.Math;
 
public class GameTimer {
    
    //number of nanoseconds in a second
    private final int NANOSECONDS = 1000000000;
 
    private boolean timerStarted;
    private int fpsCap, fps;
    private long beginTime, timeDifference;
 
    public GameTimer(int desiredFPS) {
 
        fpsCap = desiredFPS;
        fps = 0;    
        timerStarted = false;
        beginTime = 0;
        timeDifference = 0;
 
    }
 
    //timer is re-started at the beginning of every loop cycle
    public void start() {
 
        timerStarted = true;
        beginTime = System.nanoTime();
 
    }
 
    public void stop() {
 
        timerStarted = false;
        beginTime = 0;
 
    }
 
    public void syncTime() {
 
        if (timerStarted == true) {
            timeDifference = System.nanoTime() - beginTime;
        }
        else {
            timeDifference = 0;
        }
    
        if ( (timerStarted == true) && (timeDifference < (NANOSECONDS / fpsCap)) ) {
            try {
                Thread.sleep( 1000 * (NANOSECONDS - (timeDifference * fpsCap)) / fpsCap / NANOSECONDS;)
                
            }
            catch (InterruptedException e) {
                System.out.println("Exception e");
            }
        }
 
        timerStarted = false;
        beginTime = 0;
        timeDifference = 0;
        
    }
 
    public int getFPS() {
 
        return fps;
 
    }       
 
}