public boolean update() {
		if (isStarted) {
			if (enableTimeCheck) {
				if (this.currentTime > this.totoalTime) {
					this.isStarted = false;
					this.cx = this.cy = 0;
					return false;
				} else if (this.currentTime == this.totoalTime) {
					this.cx = this.x + this.dx;
					this.cy = this.y + this.dy;
					++this.currentTime;
					return true;
				} else {
					this.cx = interpolator(currentTime, x, dx, totoalTime);
					this.cy = interpolator(currentTime, y, dy, totoalTime);
					++this.currentTime;
					return true;
				}
			} else {
				this.cx = interpolator(currentTime, x, dx, totoalTime);
				this.cy = interpolator(currentTime, y, dy, totoalTime);
				if (Math.abs(this.x + this.dx - this.cx) < CHECK_RANGE_MIN && 
					Math.abs(this.y + this.dy - this.cy) < CHECK_RANGE_MIN) {
					this.isStarted = false;
					this.cx = this.x + this.dx;
					this.cy = this.y + this.dy;
					//System.out.println("SimpleTweener update is over...");
					return true;
				} else {
					++this.currentTime;
					return true;
				}
			}
		} else {
			this.cx = this.cy = 0;
			return false;
		}
	}