com.sun.javafx.embed.swing.Disposer Maven / Gradle / Ivy
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
package com.sun.javafx.embed.swing;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.Hashtable;
/**
* This class is used for registering and disposing the native
* data associated with java objects.
*
* The object can register itself by calling the addRecord method and
* providing a descendant of the DisposerRecord class with overridden
* dispose() method.
*
* When the object becomes unreachable, the dispose() method
* of the associated DisposerRecord object will be called.
*
* @see DisposerRecord
*/
public class Disposer implements Runnable {
private static final ReferenceQueue queue = new ReferenceQueue();
private static final Hashtable records = new Hashtable();
private static Disposer disposerInstance;
static {
disposerInstance = new Disposer();
ThreadGroup tg = Thread.currentThread().getThreadGroup();
@SuppressWarnings("removal")
var dummy = java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
@Override
public Object run() {
/* The thread must be a member of a thread group
* which will not get GCed before VM exit.
* Make its parent the top-level thread group.
*/
ThreadGroup tg = Thread.currentThread().getThreadGroup();
for (ThreadGroup tgn = tg;
tgn != null;
tg = tgn, tgn = tg.getParent());
Thread t =
new Thread(tg, disposerInstance, "SwingNode Disposer");
t.setContextClassLoader(null);
t.setDaemon(true);
t.setPriority(Thread.MAX_PRIORITY);
t.start();
return null;
}
}
);
}
/**
* Registers the object and the native data for later disposal.
* @param target Object to be registered
* @param rec the associated DisposerRecord object
* @see DisposerRecord
*/
public static WeakReference addRecord(Object target, DisposerRecord rec) {
WeakReference ref = new WeakReference(target, queue);
disposerInstance.records.put(ref, rec);
return ref;
}
@Override
public void run() {
while (true) {
try {
Object obj = queue.remove();
((Reference)obj).clear();
DisposerRecord rec = (DisposerRecord)records.remove(obj);
rec.dispose();
obj = null;
rec = null;
} catch (Exception e) {
System.out.println("Exception while removing reference: " + e);
e.printStackTrace();
}
}
}
}