From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libjava/java/lang/ThreadLocal.java | 198 +++++++++++++++++++++++++++++++++++++ 1 file changed, 198 insertions(+) create mode 100644 libjava/java/lang/ThreadLocal.java (limited to 'libjava/java/lang/ThreadLocal.java') diff --git a/libjava/java/lang/ThreadLocal.java b/libjava/java/lang/ThreadLocal.java new file mode 100644 index 000000000..9223dbaae --- /dev/null +++ b/libjava/java/lang/ThreadLocal.java @@ -0,0 +1,198 @@ +/* ThreadLocal -- a variable with a unique value per thread + Copyright (C) 2000, 2002, 2003, 2006 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.Map; + + +/** + * ThreadLocal objects have a different state associated with every + * Thread that accesses them. Every access to the ThreadLocal object + * (through the get() and set() methods) + * only affects the state of the object as seen by the currently + * executing Thread. + * + *

The first time a ThreadLocal object is accessed on a particular + * Thread, the state for that Thread's copy of the local variable is set by + * executing the method initialValue(). + *

+ * + *

An example how you can use this: + *

+ * + * 
+ * class Connection
+ * {
+ *   private static ThreadLocal owner = new ThreadLocal()
+ *     {
+ *       public Object initialValue()
+ *       {
+ *         return("nobody");
+ *       }
+ *     };
+ * ...
+ * }
+ *
+ * + *

Now all instances of connection can see who the owner of the currently + * executing Thread is by calling owner.get(). 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 owner.put("somebody"). + * (Such an owner changing method should then be guarded by security checks.) + *

+ * + *

When a Thread is garbage collected all references to values of + * the ThreadLocal objects associated with that Thread are removed. + *

+ * + * @author Mark Wielaard (mark@klomp.org) + * @author Eric Blake (ebb9@email.byu.edu) + * @since 1.2 + * @status updated to 1.5 + */ +public class ThreadLocal +{ + /** + * Placeholder to distinguish between uninitialized and null set by the + * user. Do not expose this to the public. Package visible for use by + * InheritableThreadLocal + */ + static final Object sentinel = new Object(); + + /** + * The base for the computation of the next hash for a thread local. + */ + private static int nextHashBase = 1; + + /** + * Allocate a new hash. + */ + private synchronized int computeNextHash() + { + return nextHashBase++ * 6709; + } + + /** + * Hash code computed for ThreadLocalMap + */ + final int fastHash; + + /** + * Creates a ThreadLocal object without associating any value to it yet. + */ + public ThreadLocal() + { + constructNative(); + fastHash = computeNextHash(); + } + + /** + * Called once per thread on the first invocation of get(), if set() was + * not already called. The default implementation returns null. + * Often, this method is overridden to create the appropriate initial object + * for the current thread's view of the ThreadLocal. + * + * @return the initial value of the variable in this thread + */ + protected T initialValue() + { + return null; + } + + /** + * Gets the value associated with the ThreadLocal object for the currently + * executing Thread. If this is the first time the current thread has called + * get(), and it has not already called set(), the value is obtained by + * initialValue(). + * + * @return the value of the variable in this thread + */ + public native T get(); + + private final Object internalGet() + { + ThreadLocalMap map = Thread.getThreadLocals(); + // Note that we don't have to synchronize, as only this thread will + // ever modify the map. + T value = (T) map.get(this); + if (value == sentinel) + { + value = initialValue(); + map.set(this, value); + } + return value; + } + + /** + * Sets the value associated with the ThreadLocal object for the currently + * executing Thread. This overrides any existing value associated with the + * current Thread and prevents initialValue() from being + * called if this is the first access to this ThreadLocal in this Thread. + * + * @param value the value to set this thread's view of the variable to + */ + public native void set(T value); + + private final void internalSet(Object value) + { + ThreadLocalMap map = Thread.getThreadLocals(); + // Note that we don't have to synchronize, as only this thread will + // ever modify the map. + map.set(this, value); + } + + /** + * Removes the value associated with the ThreadLocal object for the + * currently executing Thread. + * @since 1.5 + */ + public native void remove(); + + private final void internalRemove() + { + ThreadLocalMap map = Thread.getThreadLocals(); + map.remove(this); + } + + protected native void finalize () throws Throwable; + + private native void constructNative(); + + private gnu.gcj.RawData TLSPointer; +} -- cgit v1.2.3