1 /*
2 * Copyright (c) 2002, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.java2d;
27
28 import java.lang.ref.Reference;
29 import java.lang.ref.ReferenceQueue;
30 import java.lang.ref.PhantomReference;
31 import java.lang.ref.WeakReference;
32 import java.util.ArrayList;
33 import java.util.Hashtable;
34
35 /**
36 * This class is used for registering and disposing the native
37 * data associated with java objects.
38 *
39 * The object can register itself by calling one of the addRecord
40 * methods and providing either the pointer to the native disposal
41 * method or a descendant of the DisposerRecord class with overridden
42 * dispose() method.
43 *
44 * When the object becomes unreachable, the dispose() method
45 * of the associated DisposerRecord object will be called.
46 *
47 * @see DisposerRecord
48 */
49 public class Disposer implements Runnable {
50 private static final ReferenceQueue queue = new ReferenceQueue();
51 private static final Hashtable records = new Hashtable();
52
53 private static Disposer disposerInstance;
54 public static final int WEAK = 0;
55 public static final int PHANTOM = 1;
56 public static int refType = PHANTOM;
57
58 static {
59 java.security.AccessController.doPrivileged(
60 new java.security.PrivilegedAction<Void>() {
61 public Void run() {
62 System.loadLibrary("awt");
63 return null;
64 }
65 });
66 initIDs();
67 String type = java.security.AccessController.doPrivileged(
68 new sun.security.action.GetPropertyAction("sun.java2d.reftype"));
69 if (type != null) {
70 if (type.equals("weak")) {
71 refType = WEAK;
72 System.err.println("Using WEAK refs");
73 } else {
74 refType = PHANTOM;
75 System.err.println("Using PHANTOM refs");
76 }
77 }
78 disposerInstance = new Disposer();
79 java.security.AccessController.doPrivileged(
80 new java.security.PrivilegedAction() {
81 public Object run() {
82 /* The thread must be a member of a thread group
83 * which will not get GCed before VM exit.
84 * Make its parent the top-level thread group.
85 */
86 ThreadGroup tg = Thread.currentThread().getThreadGroup();
87 for (ThreadGroup tgn = tg;
88 tgn != null;
89 tg = tgn, tgn = tg.getParent());
90 Thread t =
91 new Thread(tg, disposerInstance, "Java2D Disposer");
92 t.setContextClassLoader(null);
93 t.setDaemon(true);
94 t.setPriority(Thread.MAX_PRIORITY);
95 t.start();
96 return null;
97 }
98 }
99 );
100 }
101
102 /**
103 * Registers the object and the native data for later disposal.
104 * @param target Object to be registered
105 * @param disposeMethod pointer to the native disposal method
106 * @param pData pointer to the data to be passed to the
107 * native disposal method
108 */
109 public static void addRecord(Object target,
110 long disposeMethod, long pData)
111 {
112 disposerInstance.add(target,
113 new DefaultDisposerRecord(disposeMethod, pData));
114 }
115
116 /**
117 * Registers the object and the native data for later disposal.
118 * @param target Object to be registered
119 * @param rec the associated DisposerRecord object
120 * @see DisposerRecord
121 */
122 public static void addRecord(Object target, DisposerRecord rec) {
123 disposerInstance.add(target, rec);
124 }
125
126 /**
127 * Performs the actual registration of the target object to be disposed.
128 * @param target Object to be registered, or if target is an instance
129 * of DisposerTarget, its associated disposer referent
130 * will be the Object that is registered
131 * @param rec the associated DisposerRecord object
132 * @see DisposerRecord
133 */
134 synchronized void add(Object target, DisposerRecord rec) {
135 if (target instanceof DisposerTarget) {
136 target = ((DisposerTarget)target).getDisposerReferent();
137 }
138 java.lang.ref.Reference ref;
139 if (refType == PHANTOM) {
140 ref = new PhantomReference(target, queue);
141 } else {
142 ref = new WeakReference(target, queue);
143 }
144 records.put(ref, rec);
145 }
146
147 public void run() {
148 while (true) {
149 try {
150 Object obj = queue.remove();
151 ((Reference)obj).clear();
152 DisposerRecord rec = (DisposerRecord)records.remove(obj);
153 rec.dispose();
154 obj = null;
155 rec = null;
156 clearDeferredRecords();
157 } catch (Exception e) {
158 System.out.println("Exception while removing reference.");
159 }
160 }
161 }
162
163 /*
164 * This is a marker interface that, if implemented, means it
165 * doesn't acquire any special locks, and is safe to
166 * be disposed in the poll loop on whatever thread
167 * which happens to be the Toolkit thread, is in use.
168 */
169 public static interface PollDisposable {
170 };
171
172 private static ArrayList<DisposerRecord> deferredRecords = null;
173
174 private static void clearDeferredRecords() {
175 if (deferredRecords == null || deferredRecords.isEmpty()) {
176 return;
177 }
178 for (int i=0;i<deferredRecords.size(); i++) {
179 try {
180 DisposerRecord rec = deferredRecords.get(i);
181 rec.dispose();
182 } catch (Exception e) {
183 System.out.println("Exception while disposing deferred rec.");
184 }
185 }
186 deferredRecords.clear();
187 }
188
189 /*
190 * Set to indicate the queue is presently being polled.
191 */
192 public static volatile boolean pollingQueue = false;
193
194 /*
195 * The pollRemove() method is called back from a dispose method
196 * that is running on the toolkit thread and wants to
197 * dispose any pending refs that are safe to be disposed
198 * on that thread.
199 */
200 public static void pollRemove() {
201
202 /* This should never be called recursively, so this check
203 * is just a safeguard against the unexpected.
204 */
205 if (pollingQueue) {
206 return;
207 }
208 Object obj;
209 pollingQueue = true;
210 int freed = 0;
211 int deferred = 0;
212 try {
213 while ((obj = queue.poll()) != null
214 && freed < 10000 && deferred < 100) {
215 freed++;
216 ((Reference)obj).clear();
217 DisposerRecord rec = (DisposerRecord)records.remove(obj);
218 if (rec instanceof PollDisposable) {
219 rec.dispose();
220 obj = null;
221 rec = null;
222 } else {
223 if (rec == null) { // shouldn't happen, but just in case.
224 continue;
225 }
226 deferred++;
227 if (deferredRecords == null) {
228 deferredRecords = new ArrayList<DisposerRecord>(5);
229 }
230 deferredRecords.add(rec);
231 }
232 }
233 } catch (Exception e) {
234 System.out.println("Exception while removing reference.");
235 } finally {
236 pollingQueue = false;
237 }
238 }
239
240 private static native void initIDs();
241
242 /*
243 * This was added for use by the 2D font implementation to avoid creation
244 * of an additional disposer thread.
245 * WARNING: this thread class monitors a specific queue, so a reference
246 * added here must have been created with this queue. Failure to do
247 * so will clutter the records hashmap and no one will be cleaning up
248 * the reference queue.
249 */
250 public static void addReference(Reference ref, DisposerRecord rec) {
251 records.put(ref, rec);
252 }
253
254 public static void addObjectRecord(Object obj, DisposerRecord rec) {
255 records.put(new WeakReference(obj, queue) , rec);
256 }
257
258 /* This is intended for use in conjunction with addReference(..)
259 */
260 public static ReferenceQueue getQueue() {
261 return queue;
262 }
263
264 }