javafx.animation.AnimationTimer Maven / Gradle / Ivy
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*
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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;
import com.sun.scenario.animation.shared.TimerReceiver;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* 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 class AnimationTimerReceiver implements TimerReceiver {
@Override public void handle(final long now) {
if (accessCtrlCtx == null) {
throw new IllegalStateException("Error: AccessControlContext not captured");
}
AccessController.doPrivileged((PrivilegedAction) () -> {
AnimationTimer.this.handle(now);
return null;
}, accessCtrlCtx);
}
}
private final AbstractMasterTimer timer;
private final AnimationTimerReceiver timerReceiver = new AnimationTimerReceiver();
private boolean active;
// Access control context, captured in start()
private AccessControlContext accessCtrlCtx = null;
/**
* Creates a new timer.
*/
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 AnimationTimer}. Once it is started, the
* {@link #handle(long)} method of this {@code AnimationTimer} will be
* called in every frame.
*
* The {@code AnimationTimer} can be stopped by calling {@link #stop()}.
*/
public void start() {
if (!active) {
// Capture the Access Control Context to be used during the animation pulse
accessCtrlCtx = AccessController.getContext();
timer.addAnimationTimer(timerReceiver);
active = true;
}
}
/**
* Stops the {@code AnimationTimer}. It can be activated again by calling
* {@link #start()}.
*/
public void stop() {
if (active) {
timer.removeAnimationTimer(timerReceiver);
active = false;
}
}
}