+++ /dev/null
-/* java.lang.ThreadLocal
- Copyright (C) 2000 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., 59 Temple Place, Suite 330, Boston, MA
-02111-1307 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.Map;
-import java.util.WeakHashMap;
-
-/**
- * ThreadLocal objects have a different state associated with every
- * Thread that accesses them. Every access to the ThreadLocal object
- * (through the <code>get()</code> and <code>set()</code> methods)
- * only affects the state of the object as seen by the currently
- * executing Thread.
- * <p>
- * The first time a ThreadLocal object is accessed on a particular
- * Thread (and no state is associated with that Thread yet)
- * the state for that Thread is set by executing the method
- * <code>initialValue()</code>.
- * <p>
- * An example how you can use this:
- * <pre>
- * class Connection {
- * private static ThreadLocal owner = new ThreadLocal() {
- * public Object initialValue() {
- * return("nobody");
- * }
- * };
- * ...
- * }
- * </pre>
- * Now all instances of connection can see who the owner of the currently
- * executing Thread is by calling <code>owner.get()</code>. By default any
- * Thread would be associated with 'nobody'. But the Connection object could
- * offer a method that changes the owner associated with the Thread on
- * which the method was called by calling <code>owner.put("somebody")</code>.
- * (Such an owner changing method should then be guarded by security checks.)
- * <p>
- * When a Thread is garbage collected all references to values of
- * the ThreadLocal objects associated with that Thread are removed.
- *
- * @since 1.2
- * @author Mark Wielaard (mark@klomp.org)
- */
-public class ThreadLocal {
-
- /**
- * Trivial container to wrap the stored values.
- * Needed to see if the value is null or not yet set.
- * If it is not yet set we must call intialValue() once.
- * Package local so InheritableThreadLocal can see it.
- */
- final static class Value {
- final Object value;
-
- Value(Object value) {
- this.value = value;
- }
-
- Object getValue() {
- return value;
- }
- }
-
- /**
- * Maps Threads to Values. Uses a WeakHashMap so if a Thread is garbage
- * collected the reference to the Value will disappear. Only the
- * <code>set(Thread, Value)</code> and <code>get(Thread)</code> methods
- * access it. Since this can happen from multiple Threads simultaniously
- * those methods are synchronized.
- */
- private final Map valueMap = new WeakHashMap();
-
- /**
- * Creates a ThreadLocal object without associating any value to it
- * yet.
- */
- public ThreadLocal() {
- }
-
- /**
- * Gets the value associated with the ThreadLocal object for the
- * currently executing Thread. If there is no value is associated
- * with this Thread yet then the valued returned by the
- * <code>initialValue()</code> method is assosiated with this Thread
- * and returned.
- */
- public Object get() {
- Thread currentThread = Thread.currentThread();
- Value v = get(currentThread);
- if (v == null) {
- v = new Value(initialValue());
- set(currentThread, v);
- }
- return v.getValue();
- }
-
- /**
- * Gets the Value of this ThreadLocal for a particular Thread.
- * It is synchronized so the <code>set(Thread, Value)</code> method cannot
- * simultaniously modify the </code>valueMap</code> from another thread.
- * Package local so InheritableThreadLocal can access it when a new child
- * Thread inherits values from its parent Thread.
- */
- synchronized final Value get(Thread thread) {
- return (Value)valueMap.get(thread);
- }
-
- /**
- * Sets the value associated with the ThreadLocal object for the
- * currently executing Thread. This overrides any existing value
- * associated with the current Thread and does not call the
- * <code>initialValue()</code> method, even if this is the first
- * time this Thread accesses this ThreadLocal.
- */
- public void set(Object value) {
- Thread currentThread = Thread.currentThread();
- Value v = new Value(value);
- set(currentThread, v);
- }
-
- /**
- * Sets the Value for this ThreadLocal for a particular Thread.
- * It is synchronized so the <code>get(Thread)</code> method cannot
- * simultaniously read the </code>valueMap</code> from another thread.
- * Package local so InheritableThreadLocal can access it when a new child
- * Thread inherits values from its parent Thread.
- */
- synchronized final void set(Thread thread, Value value) {
- valueMap.put(thread, value);
- }
-
- /**
- * Called when <code>get()</code> is called and no state is associated
- * with the currently executing Thread yet.
- * <p>
- * The default implementation returns <code>null</code>.
- */
- protected Object initialValue() {
- return null;
- }
-}
projects / msp430-gcc.git / blobdiff