Showing the changes to java/pkg/com/sun/imageio/stream/StreamCloser.java (1 of 18352 files). Show all
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| 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() { | |
| 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 | +} | |