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Diffstat (limited to 'libjava/java/lang/InheritableThreadLocal.java')
| -rw-r--r-- | libjava/java/lang/InheritableThreadLocal.java | 142 |
1 files changed, 0 insertions, 142 deletions
diff --git a/libjava/java/lang/InheritableThreadLocal.java b/libjava/java/lang/InheritableThreadLocal.java deleted file mode 100644 index b58c5bc..0000000 --- a/libjava/java/lang/InheritableThreadLocal.java +++ /dev/null @@ -1,142 +0,0 @@ -/* InheritableThreadLocal -- a ThreadLocal which inherits values across threads - Copyright (C) 2000, 2001, 2002, 2003, 2005 Free Software Foundation, Inc. - -This file is part of GNU Classpath. - -GNU Classpath is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. - -GNU Classpath 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 for more details. - -You should have received a copy of the GNU General Public License -along with GNU Classpath; see the file COPYING. If not, write to the -Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301 USA. - -Linking this library statically or dynamically with other modules is -making a combined work based on this library. Thus, the terms and -conditions of the GNU General Public License cover the whole -combination. - -As a special exception, the copyright holders of this library give you -permission to link this library with independent modules to produce an -executable, regardless of the license terms of these independent -modules, and to copy and distribute the resulting executable under -terms of your choice, provided that you also meet, for each linked -independent module, the terms and conditions of the license of that -module. An independent module is a module which is not derived from -or based on this library. If you modify this library, you may extend -this exception to your version of the library, but you are not -obligated to do so. If you do not wish to do so, delete this -exception statement from your version. */ - -package java.lang; - -import java.util.ArrayList; -import java.util.Collections; -import java.util.Iterator; -import java.util.List; -import java.util.Map; -import java.util.WeakHashMap; - -/** - * A ThreadLocal whose value is inherited by child Threads. The value of the - * InheritableThreadLocal associated with the (parent) Thread is copied to - * the new (child) Thread at the moment of creation. - * - * <p>It is possible to make the value associated with the child Thread a - * function of the value that is associated with the parent Thread by - * overriding the <code>childValue()</code> method. The utility of this class - * is in transferring items like User ID or Transaction ID across threads - * automatically. - * - * @author Mark Wielaard (mark@klomp.org) - * @author Eric Blake (ebb9@email.byu.edu) - * @see ThreadLocal - * @since 1.2 - * @status updated to 1.4 - */ -public class InheritableThreadLocal extends ThreadLocal -{ - /** - * Maps Threads to a List of InheritableThreadLocals (the heritage of that - * Thread). Uses a WeakHashMap so if the Thread is garbage collected the - * List can be collected, too. Maps to a list in case the user overrides - * equals. - */ - private static final Map threadMap - = Collections.synchronizedMap(new WeakHashMap()); - - /** - * Creates a new InheritableThreadLocal that has no values associated - * with it yet. - */ - public InheritableThreadLocal() - { - Thread currentThread = Thread.currentThread(); - // Note that we don't have to synchronize, as only this thread will - // ever modify the returned heritage and threadMap is a synchronizedMap. - List heritage = (List) threadMap.get(currentThread); - if (heritage == null) - { - heritage = new ArrayList(); - threadMap.put(currentThread, heritage); - } - heritage.add(this); - } - - /** - * Determines the value associated with a newly created child Thread as a - * function of the value associated with the currently executing (parent) - * Thread. The default implementation just returns the parentValue. - * - * @param parentValue the value of this object in the parent thread at - * the moment of creation of the child - * @return the initial value for the child thread - */ - protected Object childValue(Object parentValue) - { - return parentValue; - } - - /** - * Generates the childValues of all <code>InheritableThreadLocal</code>s - * that are in the heritage of the current Thread for the newly created - * childThread. Should be called from the contructor Thread. - * - * @param childThread the newly created thread, to inherit from this thread - * @see Thread#Thread(ThreadGroup, Runnable, String) - */ - static void newChildThread(Thread childThread) - { - // The currentThread is the parent of the new thread. - Thread parentThread = Thread.currentThread(); - // Note that we don't have to synchronize, as only this thread will - // ever modify the returned heritage and threadMap is a synchronizedMap. - ArrayList heritage = (ArrayList) threadMap.get(parentThread); - if (heritage != null) - { - threadMap.put(childThread, heritage.clone()); - // Perform the inheritance. - Iterator it = heritage.iterator(); - int i = heritage.size(); - while (--i >= 0) - { - InheritableThreadLocal local = (InheritableThreadLocal) it.next(); - Object parentValue = local.valueMap.get(parentThread); - if (parentValue != null) - { - Object childValue = local.childValue(parentValue == NULL - ? null : parentValue); - local.valueMap.put(childThread, (childValue == null - ? NULL : parentValue)); - } - } - } - } -} |