rev 9343 : 8033716: Fix raw and unchecked lint warnings in com.sun.imageio
Reviewed-by: darcy, prr, bae
1 /*
2 * Copyright (c) 2005, 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 com.sun.imageio.stream;
27
28 import java.io.IOException;
29 import java.util.Set;
30 import java.util.WeakHashMap;
31 import javax.imageio.stream.ImageInputStream;
32
33 /**
34 * This class provide means to properly close hanging
35 * image input/output streams on VM shutdown.
36 * This might be useful for proper cleanup such as removal
37 * of temporary files.
38 *
39 * Addition of stream do not prevent it from being garbage collected
40 * if no other references to it exists. Stream can be closed
41 * explicitly without removal from StreamCloser queue.
42 * Explicit removal from the queue only helps to save some memory.
43 */
44 public class StreamCloser {
45
46 private static WeakHashMap<CloseAction, Object> toCloseQueue;
47 private static Thread streamCloser;
48
49 public static void addToQueue(CloseAction ca) {
50 synchronized (StreamCloser.class) {
51 if (toCloseQueue == null) {
52 toCloseQueue =
53 new WeakHashMap<CloseAction, Object>();
54 }
55
56 toCloseQueue.put(ca, null);
57
58 if (streamCloser == null) {
59 final Runnable streamCloserRunnable = new Runnable() {
60 public void run() {
61 if (toCloseQueue != null) {
62 synchronized (StreamCloser.class) {
63 Set<CloseAction> set =
64 toCloseQueue.keySet();
65 // Make a copy of the set in order to avoid
66 // concurrent modification (the is.close()
67 // will in turn call removeFromQueue())
68 CloseAction[] actions =
69 new CloseAction[set.size()];
70 actions = set.toArray(actions);
71 for (CloseAction ca : actions) {
72 if (ca != null) {
73 try {
74 ca.performAction();
75 } catch (IOException e) {
76 }
77 }
78 }
79 }
80 }
81 }
82 };
83
84 java.security.AccessController.doPrivileged(
85 new java.security.PrivilegedAction<Object>() {
86 public Object run() {
87 /* The thread must be a member of a thread group
88 * which will not get GCed before VM exit.
89 * Make its parent the top-level thread group.
90 */
91 ThreadGroup tg =
92 Thread.currentThread().getThreadGroup();
93 for (ThreadGroup tgn = tg;
94 tgn != null;
95 tg = tgn, tgn = tg.getParent());
96 streamCloser = new Thread(tg, streamCloserRunnable);
97 /* Set context class loader to null in order to avoid
98 * keeping a strong reference to an application classloader.
99 */
100 streamCloser.setContextClassLoader(null);
101 Runtime.getRuntime().addShutdownHook(streamCloser);
102 return null;
103 }
104 });
105 }
106 }
107 }
108
109 public static void removeFromQueue(CloseAction ca) {
110 synchronized (StreamCloser.class) {
111 if (toCloseQueue != null) {
112 toCloseQueue.remove(ca);
113 }
114 }
115 }
116
117 public static CloseAction createCloseAction(ImageInputStream iis) {
118 return new CloseAction(iis);
119 }
120
121 public static final class CloseAction {
122 private ImageInputStream iis;
123
124 private CloseAction(ImageInputStream iis) {
125 this.iis = iis;
126 }
127
128 public void performAction() throws IOException {
129 if (iis != null) {
130 iis.close();
131 }
132 }
133 }
134 }
--- EOF ---