javafx.animation.AnimationTimer Maven / Gradle / Ivy

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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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package javafx.animation;

import com.sun.javafx.tk.Toolkit;
import com.sun.scenario.animation.AbstractMasterTimer;

/**
 * The class {@code AnimationTimer} allows to create a timer, that is called in
 * each frame while it is active.
 * 
 * An extending class has to override the method {@link #handle(long)} which
 * will be called in every frame.
 * 
 * The methods {@link AnimationTimer#start()} and {@link #stop()} allow to start
 * and stop the timer.
 * 
 * 
 * @since JavaFX 2.0
 */
public abstract class AnimationTimer {
    
    private final AbstractMasterTimer timer;
    private boolean active;
    
    public AnimationTimer() {
        timer = Toolkit.getToolkit().getMasterTimer();
    }
    
    // For testing only
    AnimationTimer(AbstractMasterTimer timer) {
        this.timer = timer;
    }
    
    /**
     * This method needs to be overridden by extending classes. It is going to
     * be called in every frame while the {@code AnimationTimer} is active.
     * 
     * @param now
     *            The timestamp of the current frame given in nanoseconds. This
     *            value will be the same for all {@code AnimationTimers} called
     *            during one frame.
     */
    public abstract void handle(long now);

    /**
     * Starts the {@code AnimationTimers}. Once it is started, the
     * {@link #handle(long)} method of this {@code AnimationTimers} will be
     * called in every frame.
     * 
     * The {@code AnimationTimers} can be stopped by calling {@link #stop()}.
     */
    public void start() {
        if (!active) {
            timer.addAnimationTimer(this);
            active = true;
        }
    }

    /**
     * Stops the {@code AnimationTimers}. It can be activated again by calling
     * {@link #start()}.
     */
    public void stop() {
        if (active) {
            timer.removeAnimationTimer(this);
            active = false;
        }
    }
}