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 | } | ||