com.sun.javafx.property.adapter.Disposer Maven / Gradle / Ivy
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* 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.
*
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*/
package com.sun.javafx.property.adapter;
import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* This class is used for registering and disposing various
* data associated with java objects.
*
* The object can register itself by calling the addRecord method and
* providing a descendant of the Runnable class with overridden
* run() method.
*
* When the object becomes phantom-reachable, the run() method
* of the associated Runnable object will be called.
*/
public class Disposer implements Runnable {
private static final ReferenceQueue queue = new ReferenceQueue();
private static final Map records = new ConcurrentHashMap<>();
private static Disposer disposerInstance;
static {
disposerInstance = new Disposer();
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
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, "Property Disposer");
t.setContextClassLoader(null);
t.setDaemon(true);
t.setPriority(Thread.MAX_PRIORITY);
t.start();
return null;
}
}
);
}
/**
* Registers the object and the data for later disposal.
* @param target Object to be registered
* @param rec the associated Runnable object
*/
public static void addRecord(Object target, Runnable rec) {
PhantomReference ref = new PhantomReference<>(target, queue);
records.put(ref, rec);
}
public void run() {
while (true) {
try {
Object obj = queue.remove();
((Reference)obj).clear();
Runnable rec = (Runnable)records.remove(obj);
rec.run();
} catch (Exception e) {
System.out.println("Exception while removing reference: " + e);
e.printStackTrace();
}
}
}
}