| /* |
| * Copyright (c) 2005, 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.imageio.stream; |
| |
| import sun.awt.util.ThreadGroupUtils; |
| |
| import java.io.IOException; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.Set; |
| import java.util.WeakHashMap; |
| import javax.imageio.stream.ImageInputStream; |
| |
| /** |
| * This class provide means to properly close hanging |
| * image input/output streams on VM shutdown. |
| * This might be useful for proper cleanup such as removal |
| * of temporary files. |
| * |
| * Addition of stream do not prevent it from being garbage collected |
| * if no other references to it exists. Stream can be closed |
| * explicitly without removal from StreamCloser queue. |
| * Explicit removal from the queue only helps to save some memory. |
| */ |
| public class StreamCloser { |
| |
| private static WeakHashMap<CloseAction, Object> toCloseQueue; |
| private static Thread streamCloser; |
| |
| public static void addToQueue(CloseAction ca) { |
| synchronized (StreamCloser.class) { |
| if (toCloseQueue == null) { |
| toCloseQueue = |
| new WeakHashMap<CloseAction, Object>(); |
| } |
| |
| toCloseQueue.put(ca, null); |
| |
| if (streamCloser == null) { |
| final Runnable streamCloserRunnable = new Runnable() { |
| public void run() { |
| if (toCloseQueue != null) { |
| synchronized (StreamCloser.class) { |
| Set<CloseAction> set = |
| toCloseQueue.keySet(); |
| // Make a copy of the set in order to avoid |
| // concurrent modification (the is.close() |
| // will in turn call removeFromQueue()) |
| CloseAction[] actions = |
| new CloseAction[set.size()]; |
| actions = set.toArray(actions); |
| for (CloseAction ca : actions) { |
| if (ca != null) { |
| try { |
| ca.performAction(); |
| } catch (IOException e) { |
| } |
| } |
| } |
| } |
| } |
| } |
| }; |
| |
| AccessController.doPrivileged((PrivilegedAction<Object>) () -> { |
| /* The thread must be a member of a thread group |
| * which will not get GCed before VM exit. |
| * Make its parent the top-level thread group. |
| */ |
| ThreadGroup tg = ThreadGroupUtils.getRootThreadGroup(); |
| streamCloser = new Thread(tg, streamCloserRunnable, |
| "StreamCloser", 0, false); |
| /* Set context class loader to null in order to avoid |
| * keeping a strong reference to an application classloader. |
| */ |
| streamCloser.setContextClassLoader(null); |
| Runtime.getRuntime().addShutdownHook(streamCloser); |
| return null; |
| }); |
| } |
| } |
| } |
| |
| public static void removeFromQueue(CloseAction ca) { |
| synchronized (StreamCloser.class) { |
| if (toCloseQueue != null) { |
| toCloseQueue.remove(ca); |
| } |
| } |
| } |
| |
| public static CloseAction createCloseAction(ImageInputStream iis) { |
| return new CloseAction(iis); |
| } |
| |
| public static final class CloseAction { |
| private ImageInputStream iis; |
| |
| private CloseAction(ImageInputStream iis) { |
| this.iis = iis; |
| } |
| |
| public void performAction() throws IOException { |
| if (iis != null) { |
| iis.close(); |
| } |
| } |
| } |
| } |