/*
* Copyright (c) 2002, 2015, 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
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*/
package sun.java2d;
import sun.awt.util.ThreadGroupUtils;
import sun.misc.ManagedLocalsThread;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.PhantomReference;
import java.lang.ref.WeakReference;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
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 one of the addRecord
* methods and providing either the pointer to the native disposal
* method or 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<Object> queue = new ReferenceQueue<>();
private static final Hashtable<java.lang.ref.Reference<Object>, DisposerRecord> records =
new Hashtable<>();
private static Disposer disposerInstance;
public static final int WEAK = 0;
public static final int PHANTOM = 1;
public static int refType = PHANTOM;
static {
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction<Void>() {
public Void run() {
System.loadLibrary("awt");
return null;
}
});
initIDs();
String type = java.security.AccessController.doPrivileged(
new sun.security.action.GetPropertyAction("sun.java2d.reftype"));
if (type != null) {
if (type.equals("weak")) {
refType = WEAK;
System.err.println("Using WEAK refs");
} else {
refType = PHANTOM;
System.err.println("Using PHANTOM refs");
}
}
disposerInstance = new Disposer();
AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
String name = "Java2D Disposer";
ThreadGroup rootTG = ThreadGroupUtils.getRootThreadGroup();
Thread t = new ManagedLocalsThread(rootTG, disposerInstance, name);
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 disposeMethod pointer to the native disposal method
* @param pData pointer to the data to be passed to the
* native disposal method
*/
public static void addRecord(Object target,
long disposeMethod, long pData)
{
disposerInstance.add(target,
new DefaultDisposerRecord(disposeMethod, pData));
}
/**
* 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 void addRecord(Object target, DisposerRecord rec) {
disposerInstance.add(target, rec);
}
/**
* Performs the actual registration of the target object to be disposed.
* @param target Object to be registered, or if target is an instance
* of DisposerTarget, its associated disposer referent
* will be the Object that is registered
* @param rec the associated DisposerRecord object
* @see DisposerRecord
*/
synchronized void add(Object target, DisposerRecord rec) {
if (target instanceof DisposerTarget) {
target = ((DisposerTarget)target).getDisposerReferent();
}
java.lang.ref.Reference<Object> ref;
if (refType == PHANTOM) {
ref = new PhantomReference<>(target, queue);
} else {
ref = new WeakReference<>(target, queue);
}
records.put(ref, rec);
}
public void run() {
while (true) {
try {
Object obj = queue.remove();
((Reference)obj).clear();
DisposerRecord rec = records.remove(obj);
rec.dispose();
obj = null;
rec = null;
clearDeferredRecords();
} catch (Exception e) {
System.out.println("Exception while removing reference.");
}
}
}
/*
* This is a marker interface that, if implemented, means it
* doesn't acquire any special locks, and is safe to
* be disposed in the poll loop on whatever thread
* which happens to be the Toolkit thread, is in use.
*/
public static interface PollDisposable {
};
private static ArrayList<DisposerRecord> deferredRecords = null;
private static void clearDeferredRecords() {
if (deferredRecords == null || deferredRecords.isEmpty()) {
return;
}
for (int i=0;i<deferredRecords.size(); i++) {
try {
DisposerRecord rec = deferredRecords.get(i);
rec.dispose();
} catch (Exception e) {
System.out.println("Exception while disposing deferred rec.");
}
}
deferredRecords.clear();
}
/*
* Set to indicate the queue is presently being polled.
*/
public static volatile boolean pollingQueue = false;
/*
* The pollRemove() method is called back from a dispose method
* that is running on the toolkit thread and wants to
* dispose any pending refs that are safe to be disposed
* on that thread.
*/
public static void pollRemove() {
/* This should never be called recursively, so this check
* is just a safeguard against the unexpected.
*/
if (pollingQueue) {
return;
}
Object obj;
pollingQueue = true;
int freed = 0;
int deferred = 0;
try {
while ( freed < 10000 && deferred < 100 &&
(obj = queue.poll()) != null ) {
freed++;
((Reference)obj).clear();
DisposerRecord rec = records.remove(obj);
if (rec instanceof PollDisposable) {
rec.dispose();
obj = null;
rec = null;
} else {
if (rec == null) { // shouldn't happen, but just in case.
continue;
}
deferred++;
if (deferredRecords == null) {
deferredRecords = new ArrayList<DisposerRecord>(5);
}
deferredRecords.add(rec);
}
}
} catch (Exception e) {
System.out.println("Exception while removing reference.");
} finally {
pollingQueue = false;
}
}
private static native void initIDs();
/*
* This was added for use by the 2D font implementation to avoid creation
* of an additional disposer thread.
* WARNING: this thread class monitors a specific queue, so a reference
* added here must have been created with this queue. Failure to do
* so will clutter the records hashmap and no one will be cleaning up
* the reference queue.
*/
@SuppressWarnings("unchecked")
public static void addReference(Reference<Object> ref, DisposerRecord rec) {
records.put(ref, rec);
}
public static void addObjectRecord(Object obj, DisposerRecord rec) {
records.put(new WeakReference<>(obj, queue) , rec);
}
/* This is intended for use in conjunction with addReference(..)
*/
public static ReferenceQueue<Object> getQueue() {
return queue;
}
}