JavaFX Why AnimationTimer has not getStatus() or similar method? - javafx

Question

It seems pretty strange that AnimationTimer has not a method to know if it is running or not.... And i am facing this problem, cause sometimes it is starting and sometimes not.
A solution is creating a volatile variable inside the handle() method and every time it is running inside the handle to make it true and every time it enters stop()) method to make it false.So i have to #Override both methods.
The Question:
Why the AnimationTimer has not a method to determine if it is running?
Is it a bad design it is missing for some reason?
Relative questions:
Is AnimationTimer running in its own thread?
How can I know if an AnimationTimer is running?

Answer 1

It is indeed very strange that this method is missing but with the exception of you and me nobody seems to care. I have reported this issue
more than 4 years ago and nothing has happened since then although the fix seems to be trivial.
JDK-8092345

Answer 2

From now it has the method isRunning() until bro's from Oracle add it🐠.
By looking here although it is not present in Java 9 http://download.java.net/java/jdk9/jfxdocs/javafx/animation/AnimationTimer.html.
AnimationTimer code:
/*
* Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
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<Void>) () -> {
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 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) {
// Capture the Access Control Context to be used during the animation pulse
accessCtrlCtx = AccessController.getContext();
timer.addAnimationTimer(timerReceiver);
active = true;
}
}
/**
* Stops the {#code AnimationTimers}. It can be activated again by calling
* {#link #start()}.
*/
public void stop() {
if (active) {
timer.removeAnimationTimer(timerReceiver);
active = false;
}
}
/**Determines if the AnimationTimer is Running
* #return True if it is running
*/
public boolean isRunning() {
return active;
}
}