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[Jnode-svn-commits] SF.net SVN: jnode:[5099] trunk
|
From: <ls...@us...> - 2009-03-13 20:11:36
|
Revision: 5099
http://jnode.svn.sourceforge.net/jnode/?rev=5099&view=rev
Author: lsantha
Date: 2009-03-13 20:11:26 +0000 (Fri, 13 Mar 2009)
Log Message:
-----------
OpenJDK integration.
Modified Paths:
--------------
trunk/all/conf/openjdk-annotations.properties
trunk/core/src/classpath/vm/java/lang/Thread.java
Added Paths:
-----------
trunk/core/src/openjdk/java/java/lang/InheritableThreadLocal.java
trunk/core/src/openjdk/java/java/lang/ThreadLocal.java
Removed Paths:
-------------
trunk/core/src/classpath/java/java/lang/InheritableThreadLocal.java
trunk/core/src/classpath/java/java/lang/ThreadLocal.java
Modified: trunk/all/conf/openjdk-annotations.properties
===================================================================
--- trunk/all/conf/openjdk-annotations.properties 2009-03-13 20:07:21 UTC (rev 5098)
+++ trunk/all/conf/openjdk-annotations.properties 2009-03-13 20:11:26 UTC (rev 5099)
@@ -5,16 +5,17 @@
# package/className.class=<annotations list separated by a ','>
# supported annotations : SharedStatics, MagicPermission
-java/lang/Throwable.class=MagicPermission
-java/util/Currency.class=SharedStatics
-sun/misc/SharedSecrets.class=SharedStatics
-sun/misc/Unsafe.class=SharedStatics
java/awt/EventQueue.class=SharedStatics
+java/awt/image/DataBuffer.class=SharedStatics
java/awt/KeyboardFocusManager.class=SharedStatics
java/awt/Toolkit.class=SharedStatics
+java/lang/ThreadLocal.class=SharedStatics
+java/lang/Throwable.class=MagicPermission
+java/util/Currency.class=SharedStatics
+java/util/concurrent/locks/LockSupport.class=SharedStatics
sun/awt/AppContext.class=SharedStatics
sun/awt/AWTAutoShutdown.class=SharedStatics
sun/awt/image/SunWritableRaster.class=SharedStatics
sun/java2d/Disposer.class=SharedStatics
-java/awt/image/DataBuffer.class=SharedStatics
-java/util/concurrent/locks/LockSupport.class=SharedStatics
+sun/misc/SharedSecrets.class=SharedStatics
+sun/misc/Unsafe.class=SharedStatics
Deleted: trunk/core/src/classpath/java/java/lang/InheritableThreadLocal.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/InheritableThreadLocal.java 2009-03-13 20:07:21 UTC (rev 5098)
+++ trunk/core/src/classpath/java/java/lang/InheritableThreadLocal.java 2009-03-13 20:11:26 UTC (rev 5099)
@@ -1,119 +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.Iterator;
-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 (ma...@kl...)
- * @author Eric Blake (eb...@em...)
- * @author Tom Tromey (tr...@re...)
- * @author Andrew John Hughes (gnu...@me...)
- * @see ThreadLocal
- * @since 1.2
- * @status updated to 1.4
- */
-public class InheritableThreadLocal<T> extends ThreadLocal<T>
-{
-
- /**
- * Creates a new InheritableThreadLocal that has no values associated
- * with it yet.
- */
- public InheritableThreadLocal()
- {
- }
-
- /**
- * 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();
- if (parentThread.locals != null)
- {
- Iterator keys = parentThread.locals.keySet().iterator();
- while (keys.hasNext())
- {
- ThreadLocal.Key key = (ThreadLocal.Key)keys.next();
- if (key.get() instanceof InheritableThreadLocal)
- {
- InheritableThreadLocal local = (InheritableThreadLocal)key.get();
- Object parentValue = parentThread.locals.get(key);
- Object childValue = local.childValue(parentValue == NULL
- ? null : parentValue);
- if (childThread.locals == null)
- childThread.locals = new WeakHashMap();
- childThread.locals.put(key, (childValue == null
- ? NULL : childValue));
- }
- }
- }
- }
-}
Deleted: trunk/core/src/classpath/java/java/lang/ThreadLocal.java
===================================================================
--- trunk/core/src/classpath/java/java/lang/ThreadLocal.java 2009-03-13 20:07:21 UTC (rev 5098)
+++ trunk/core/src/classpath/java/java/lang/ThreadLocal.java 2009-03-13 20:11:26 UTC (rev 5099)
@@ -1,181 +0,0 @@
-/* ThreadLocal -- a variable with a unique value per thread
- Copyright (C) 2000, 2002, 2003 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 <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, the state for that Thread's copy of the local variable is set by
- * executing the method <code>initialValue()</code>.
- * </p>
- *
- * <p>An example how you can use this:
- * </p>
- *
- * <pre>
- * class Connection
- * {
- * private static ThreadLocal owner = new ThreadLocal()
- * {
- * public Object initialValue()
- * {
- * return("nobody");
- * }
- * };
- * ...
- * }
- * </pre>
- *
- * <p>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>
- *
- * <p>When a Thread is garbage collected all references to values of
- * the ThreadLocal objects associated with that Thread are removed.
- * </p>
- *
- * @author Mark Wielaard (ma...@kl...)
- * @author Eric Blake (eb...@em...)
- * @since 1.2
- * @status updated to 1.5
- */
-public class ThreadLocal<T>
-{
- /**
- * 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 NULL = new Object();
-
- /**
- * Serves as a key for the Thread.locals WeakHashMap.
- * We can't use "this", because a subclass may override equals/hashCode
- * and we need to use object identity for the map.
- */
- final Key key = new Key();
-
- class Key
- {
- ThreadLocal get()
- {
- return ThreadLocal.this;
- }
- }
-
- /**
- * Creates a ThreadLocal object without associating any value to it yet.
- */
- public ThreadLocal()
- {
- }
-
- /**
- * Called once per thread on the first invocation of get(), if set() was
- * not already called. The default implementation returns <code>null</code>.
- * 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
- * <code>initialValue()</code>.
- *
- * @return the value of the variable in this thread
- */
- public T get()
- {
- Map map = Thread.getThreadLocals();
- // Note that we don't have to synchronize, as only this thread will
- // ever modify the map.
- Object value = map.get(key);
- if (value == null)
- {
- value = initialValue();
- map.put(key, value == null ? NULL : value);
- }
- return value == NULL ? null : (T) 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 <code>initialValue()</code> 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 void set(T value)
- {
- Map map = Thread.getThreadLocals();
- // Note that we don't have to synchronize, as only this thread will
- // ever modify the map.
- map.put(key, value == null ? NULL : value);
- }
-
- /**
- * Removes the value associated with the ThreadLocal object for the
- * currently executing Thread.
- * @since 1.5
- */
- public void remove()
- {
- Map map = Thread.getThreadLocals();
- map.remove(this);
-}
-}
Modified: trunk/core/src/classpath/vm/java/lang/Thread.java
===================================================================
--- trunk/core/src/classpath/vm/java/lang/Thread.java 2009-03-13 20:07:21 UTC (rev 5098)
+++ trunk/core/src/classpath/vm/java/lang/Thread.java 2009-03-13 20:11:26 UTC (rev 5099)
@@ -39,7 +39,6 @@
package java.lang;
import java.util.Map;
-import java.util.WeakHashMap;
import java.util.HashMap;
@@ -101,7 +100,6 @@
* @see #start()
* @see ThreadLocal
* @since 1.0
- * @status updated to 1.4
*/
@SharedStatics
public class Thread implements Runnable
@@ -141,15 +139,20 @@
private final Thread parent;
/** The default exception handler. */
- private static UncaughtExceptionHandler defaultHandler;
+ private static UncaughtExceptionHandler defaultHandler;
- /** Thread local storage. Package accessible for use by
- * InheritableThreadLocal.
+ /* ThreadLocal values pertaining to this thread. This map is maintained
+ * by the ThreadLocal class. */
+ ThreadLocal.ThreadLocalMap threadLocals = null;
+
+ /*
+ * InheritableThreadLocal values pertaining to this thread. This map is
+ * maintained by the InheritableThreadLocal class.
*/
- WeakHashMap locals;
+ ThreadLocal.ThreadLocalMap inheritableThreadLocals = null;
/** The uncaught exception handler. */
- UncaughtExceptionHandler exceptionHandler;
+ UncaughtExceptionHandler exceptionHandler;
/**
* Name and number of threads created. Used only for generating unique names.
@@ -158,8 +161,7 @@
*/
private static final HashMap<String, Integer> nameMap = new HashMap<String, Integer>();
- private static final JNodePermission GETVMTHREAD_PERM = new JNodePermission(
- "getVmThread");
+ private static final JNodePermission GETVMTHREAD_PERM = new JNodePermission("getVmThread");
/**
* Allocates a new <code>Thread</code> object. This constructor has
@@ -345,8 +347,9 @@
this.vmThread = VmProcessor.current().createThread(this);
this.vmThread.setPriority(current.getPriority());
this.vmThread.updateName();
-
- InheritableThreadLocal.newChildThread(this); // FDy : CLASSPATH patch ?
+
+ if (parent.inheritableThreadLocals != null)
+ this.inheritableThreadLocals = ThreadLocal.createInheritedMap(parent.inheritableThreadLocals);
}
/**
@@ -396,7 +399,8 @@
this.vmThread.setPriority(current.getPriority());
this.vmThread.updateName();
- InheritableThreadLocal.newChildThread(this); // FDy : CLASSPATH patch ?
+ if (parent.inheritableThreadLocals != null)
+ this.inheritableThreadLocals = ThreadLocal.createInheritedMap(parent.inheritableThreadLocals);
}
/**
@@ -431,8 +435,11 @@
this.vmThread = VmProcessor.current().createThread(isolatedStatics, this);
this.vmThread.setPriority(this.getPriority());
this.vmThread.updateName();
-
- InheritableThreadLocal.newChildThread(this); // FDy : CLASSPATH patch ?
+
+ //todo review it: should thread locals be inherited accorss isolates? Probably not...
+ ThreadLocal.ThreadLocalMap parentLocals = currentThread().inheritableThreadLocals;
+ if (parentLocals != null)
+ this.inheritableThreadLocals = ThreadLocal.createInheritedMap(parentLocals);
}
/**
@@ -1067,19 +1074,6 @@
}
/**
- * Returns the map used by ThreadLocal to store the thread local values.
- */
- static Map getThreadLocals() {
- Thread thread = currentThread();
- Map locals = thread.locals;
- if (locals == null)
- {
- locals = thread.locals = new WeakHashMap();
- }
- return locals;
- }
-
- /**
* Assigns the given <code>UncaughtExceptionHandler</code> to this
* thread. This will then be called if the thread terminates due
* to an uncaught exception, pre-empting that of the
@@ -1213,6 +1207,8 @@
public final void onExit() {
if (vmThread.isStopping()) {
group.remove(this);
+ threadLocals = null;
+ inheritableThreadLocals = null;
}
}
@@ -1466,5 +1462,4 @@
// blocker = b;
// }
}
-
}
Added: trunk/core/src/openjdk/java/java/lang/InheritableThreadLocal.java
===================================================================
--- trunk/core/src/openjdk/java/java/lang/InheritableThreadLocal.java (rev 0)
+++ trunk/core/src/openjdk/java/java/lang/InheritableThreadLocal.java 2009-03-13 20:11:26 UTC (rev 5099)
@@ -0,0 +1,84 @@
+/*
+ * Copyright 1998-2004 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.lang;
+import java.lang.ref.*;
+
+/**
+ * This class extends <tt>ThreadLocal</tt> to provide inheritance of values
+ * from parent thread to child thread: when a child thread is created, the
+ * child receives initial values for all inheritable thread-local variables
+ * for which the parent has values. Normally the child's values will be
+ * identical to the parent's; however, the child's value can be made an
+ * arbitrary function of the parent's by overriding the <tt>childValue</tt>
+ * method in this class.
+ *
+ * <p>Inheritable thread-local variables are used in preference to
+ * ordinary thread-local variables when the per-thread-attribute being
+ * maintained in the variable (e.g., User ID, Transaction ID) must be
+ * automatically transmitted to any child threads that are created.
+ *
+ * @author Josh Bloch and Doug Lea
+ * @see ThreadLocal
+ * @since 1.2
+ */
+
+public class InheritableThreadLocal<T> extends ThreadLocal<T> {
+ /**
+ * Computes the child's initial value for this inheritable thread-local
+ * variable as a function of the parent's value at the time the child
+ * thread is created. This method is called from within the parent
+ * thread before the child is started.
+ * <p>
+ * This method merely returns its input argument, and should be overridden
+ * if a different behavior is desired.
+ *
+ * @param parentValue the parent thread's value
+ * @return the child thread's initial value
+ */
+ protected T childValue(T parentValue) {
+ return parentValue;
+ }
+
+ /**
+ * Get the map associated with a ThreadLocal.
+ *
+ * @param t the current thread
+ */
+ ThreadLocalMap getMap(Thread t) {
+ return t.inheritableThreadLocals;
+ }
+
+ /**
+ * Create the map associated with a ThreadLocal.
+ *
+ * @param t the current thread
+ * @param firstValue value for the initial entry of the table.
+ * @param map the map to store.
+ */
+ void createMap(Thread t, T firstValue) {
+ t.inheritableThreadLocals = new ThreadLocalMap(this, firstValue);
+ }
+}
Added: trunk/core/src/openjdk/java/java/lang/ThreadLocal.java
===================================================================
--- trunk/core/src/openjdk/java/java/lang/ThreadLocal.java (rev 0)
+++ trunk/core/src/openjdk/java/java/lang/ThreadLocal.java 2009-03-13 20:11:26 UTC (rev 5099)
@@ -0,0 +1,697 @@
+/*
+ * Copyright 1997-2007 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.lang;
+import java.lang.ref.*;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * This class provides thread-local variables. These variables differ from
+ * their normal counterparts in that each thread that accesses one (via its
+ * <tt>get</tt> or <tt>set</tt> method) has its own, independently initialized
+ * copy of the variable. <tt>ThreadLocal</tt> instances are typically private
+ * static fields in classes that wish to associate state with a thread (e.g.,
+ * a user ID or Transaction ID).
+ *
+ * <p>For example, the class below generates unique identifiers local to each
+ * thread.
+ * A thread's id is assigned the first time it invokes <tt>ThreadId.get()</tt>
+ * and remains unchanged on subsequent calls.
+ * <pre>
+ * import java.util.concurrent.atomic.AtomicInteger;
+ *
+ * public class ThreadId {
+ * // Atomic integer containing the next thread ID to be assigned
+ * private static final AtomicInteger nextId = new AtomicInteger(0);
+ *
+ * // Thread local variable containing each thread's ID
+ * private static final ThreadLocal<Integer> threadId =
+ * new ThreadLocal<Integer>() {
+ * @Override protected Integer initialValue() {
+ * return nextId.getAndIncrement();
+ * }
+ * };
+ *
+ * // Returns the current thread's unique ID, assigning it if necessary
+ * public static int get() {
+ * return threadId.get();
+ * }
+ * }
+ * </pre>
+ * <p>Each thread holds an implicit reference to its copy of a thread-local
+ * variable as long as the thread is alive and the <tt>ThreadLocal</tt>
+ * instance is accessible; after a thread goes away, all of its copies of
+ * thread-local instances are subject to garbage collection (unless other
+ * references to these copies exist).
+ *
+ * @author Josh Bloch and Doug Lea
+ * @since 1.2
+ */
+public class ThreadLocal<T> {
+ /**
+ * ThreadLocals rely on per-thread linear-probe hash maps attached
+ * to each thread (Thread.threadLocals and
+ * inheritableThreadLocals). The ThreadLocal objects act as keys,
+ * searched via threadLocalHashCode. This is a custom hash code
+ * (useful only within ThreadLocalMaps) that eliminates collisions
+ * in the common case where consecutively constructed ThreadLocals
+ * are used by the same threads, while remaining well-behaved in
+ * less common cases.
+ */
+ private final int threadLocalHashCode = nextHashCode();
+
+ /**
+ * The next hash code to be given out. Updated atomically. Starts at
+ * zero.
+ */
+//jnode todo: unsing AtomicInteger here breaks the boot process, why?
+// private static AtomicInteger nextHashCode =
+// new AtomicInteger();
+ private static Integer nextHashCode = 0;
+
+ /**
+ * The difference between successively generated hash codes - turns
+ * implicit sequential thread-local IDs into near-optimally spread
+ * multiplicative hash values for power-of-two-sized tables.
+ */
+ private static final int HASH_INCREMENT = 0x61c88647;
+
+ /**
+ * Returns the next hash code.
+ */
+ private static int nextHashCode() {
+// return nextHashCode.getAndAdd(HASH_INCREMENT);
+ return nextHashCode += HASH_INCREMENT;
+ }
+
+ /**
+ * Returns the current thread's "initial value" for this
+ * thread-local variable. This method will be invoked the first
+ * time a thread accesses the variable with the {@link #get}
+ * method, unless the thread previously invoked the {@link #set}
+ * method, in which case the <tt>initialValue</tt> method will not
+ * be invoked for the thread. Normally, this method is invoked at
+ * most once per thread, but it may be invoked again in case of
+ * subsequent invocations of {@link #remove} followed by {@link #get}.
+ *
+ * <p>This implementation simply returns <tt>null</tt>; if the
+ * programmer desires thread-local variables to have an initial
+ * value other than <tt>null</tt>, <tt>ThreadLocal</tt> must be
+ * subclassed, and this method overridden. Typically, an
+ * anonymous inner class will be used.
+ *
+ * @return the initial value for this thread-local
+ */
+ protected T initialValue() {
+ return null;
+ }
+
+ /**
+ * Creates a thread local variable.
+ */
+ public ThreadLocal() {
+ }
+
+ /**
+ * Returns the value in the current thread's copy of this
+ * thread-local variable. If the variable has no value for the
+ * current thread, it is first initialized to the value returned
+ * by an invocation of the {@link #initialValue} method.
+ *
+ * @return the current thread's value of this thread-local
+ */
+ public T get() {
+ Thread t = Thread.currentThread();
+ ThreadLocalMap map = getMap(t);
+ if (map != null) {
+ ThreadLocalMap.Entry e = map.getEntry(this);
+ if (e != null)
+ return (T)e.value;
+ }
+ return setInitialValue();
+ }
+
+ /**
+ * Variant of set() to establish initialValue. Used instead
+ * of set() in case user has overridden the set() method.
+ *
+ * @return the initial value
+ */
+ private T setInitialValue() {
+ T value = initialValue();
+ Thread t = Thread.currentThread();
+ ThreadLocalMap map = getMap(t);
+ if (map != null)
+ map.set(this, value);
+ else
+ createMap(t, value);
+ return value;
+ }
+
+ /**
+ * Sets the current thread's copy of this thread-local variable
+ * to the specified value. Most subclasses will have no need to
+ * override this method, relying solely on the {@link #initialValue}
+ * method to set the values of thread-locals.
+ *
+ * @param value the value to be stored in the current thread's copy of
+ * this thread-local.
+ */
+ public void set(T value) {
+ Thread t = Thread.currentThread();
+ ThreadLocalMap map = getMap(t);
+ if (map != null)
+ map.set(this, value);
+ else
+ createMap(t, value);
+ }
+
+ /**
+ * Removes the current thread's value for this thread-local
+ * variable. If this thread-local variable is subsequently
+ * {@linkplain #get read} by the current thread, its value will be
+ * reinitialized by invoking its {@link #initialValue} method,
+ * unless its value is {@linkplain #set set} by the current thread
+ * in the interim. This may result in multiple invocations of the
+ * <tt>initialValue</tt> method in the current thread.
+ *
+ * @since 1.5
+ */
+ public void remove() {
+ ThreadLocalMap m = getMap(Thread.currentThread());
+ if (m != null)
+ m.remove(this);
+ }
+
+ /**
+ * Get the map associated with a ThreadLocal. Overridden in
+ * InheritableThreadLocal.
+ *
+ * @param t the current thread
+ * @return the map
+ */
+ ThreadLocalMap getMap(Thread t) {
+ return t.threadLocals;
+ }
+
+ /**
+ * Create the map associated with a ThreadLocal. Overridden in
+ * InheritableThreadLocal.
+ *
+ * @param t the current thread
+ * @param firstValue value for the initial entry of the map
+ * @param map the map to store.
+ */
+ void createMap(Thread t, T firstValue) {
+ t.threadLocals = new ThreadLocalMap(this, firstValue);
+ }
+
+ /**
+ * Factory method to create map of inherited thread locals.
+ * Designed to be called only from Thread constructor.
+ *
+ * @param parentMap the map associated with parent thread
+ * @return a map containing the parent's inheritable bindings
+ */
+ static ThreadLocalMap createInheritedMap(ThreadLocalMap parentMap) {
+ return new ThreadLocalMap(parentMap);
+ }
+
+ /**
+ * Method childValue is visibly defined in subclass
+ * InheritableThreadLocal, but is internally defined here for the
+ * sake of providing createInheritedMap factory method without
+ * needing to subclass the map class in InheritableThreadLocal.
+ * This technique is preferable to the alternative of embedding
+ * instanceof tests in methods.
+ */
+ T childValue(T parentValue) {
+ throw new UnsupportedOperationException();
+ }
+
+ /**
+ * ThreadLocalMap is a customized hash map suitable only for
+ * maintaining thread local values. No operations are exported
+ * outside of the ThreadLocal class. The class is package private to
+ * allow declaration of fields in class Thread. To help deal with
+ * very large and long-lived usages, the hash table entries use
+ * WeakReferences for keys. However, since reference queues are not
+ * used, stale entries are guaranteed to be removed only when
+ * the table starts running out of space.
+ */
+ static class ThreadLocalMap {
+
+ /**
+ * The entries in this hash map extend WeakReference, using
+ * its main ref field as the key (which is always a
+ * ThreadLocal object). Note that null keys (i.e. entry.get()
+ * == null) mean that the key is no longer referenced, so the
+ * entry can be expunged from table. Such entries are referred to
+ * as "stale entries" in the code that follows.
+ */
+ static class Entry { //jnode
+ /** The value associated with this ThreadLocal. */
+ Object value;
+ ThreadLocal k;
+
+ public ThreadLocal get() {
+ return k;
+ }
+
+ public void clear() {
+ k = null;
+ }
+
+ Entry(ThreadLocal k, Object v) {
+ this.k = k;
+ value = v;
+ }
+ }
+
+ /**
+ * The initial capacity -- MUST be a power of two.
+ */
+ private static final int INITIAL_CAPACITY = 16;
+
+ /**
+ * The table, resized as necessary.
+ * table.length MUST always be a power of two.
+ */
+ private Entry[] table;
+
+ /**
+ * The number of entries in the table.
+ */
+ private int size = 0;
+
+ /**
+ * The next size value at which to resize.
+ */
+ private int threshold; // Default to 0
+
+ /**
+ * Set the resize threshold to maintain at worst a 2/3 load factor.
+ */
+ private void setThreshold(int len) {
+ threshold = len * 2 / 3;
+ }
+
+ /**
+ * Increment i modulo len.
+ */
+ private static int nextIndex(int i, int len) {
+ return ((i + 1 < len) ? i + 1 : 0);
+ }
+
+ /**
+ * Decrement i modulo len.
+ */
+ private static int prevIndex(int i, int len) {
+ return ((i - 1 >= 0) ? i - 1 : len - 1);
+ }
+
+ /**
+ * Construct a new map initially containing (firstKey, firstValue).
+ * ThreadLocalMaps are constructed lazily, so we only create
+ * one when we have at least one entry to put in it.
+ */
+ ThreadLocalMap(ThreadLocal firstKey, Object firstValue) {
+ table = new Entry[INITIAL_CAPACITY];
+ int i = firstKey.threadLocalHashCode & (INITIAL_CAPACITY - 1);
+ table[i] = new Entry(firstKey, firstValue);
+ size = 1;
+ setThreshold(INITIAL_CAPACITY);
+ }
+
+ /**
+ * Construct a new map including all Inheritable ThreadLocals
+ * from given parent map. Called only by createInheritedMap.
+ *
+ * @param parentMap the map associated with parent thread.
+ */
+ private ThreadLocalMap(ThreadLocalMap parentMap) {
+ Entry[] parentTable = parentMap.table;
+ int len = parentTable.length;
+ setThreshold(len);
+ table = new Entry[len];
+
+ for (int j = 0; j < len; j++) {
+ Entry e = parentTable[j];
+ if (e != null) {
+ ThreadLocal key = e.get();
+ if (key != null) {
+ Object value = key.childValue(e.value);
+ Entry c = new Entry(key, value);
+ int h = key.threadLocalHashCode & (len - 1);
+ while (table[h] != null)
+ h = nextIndex(h, len);
+ table[h] = c;
+ size++;
+ }
+ }
+ }
+ }
+
+ /**
+ * Get the entry associated with key. This method
+ * itself handles only the fast path: a direct hit of existing
+ * key. It otherwise relays to getEntryAfterMiss. This is
+ * designed to maximize performance for direct hits, in part
+ * by making this method readily inlinable.
+ *
+ * @param key the thread local object
+ * @return the entry associated with key, or null if no such
+ */
+ private Entry getEntry(ThreadLocal key) {
+ int i = key.threadLocalHashCode & (table.length - 1);
+ Entry e = table[i];
+ if (e != null && e.get() == key)
+ return e;
+ else
+ return getEntryAfterMiss(key, i, e);
+ }
+
+ /**
+ * Version of getEntry method for use when key is not found in
+ * its direct hash slot.
+ *
+ * @param key the thread local object
+ * @param i the table index for key's hash code
+ * @param e the entry at table[i]
+ * @return the entry associated with key, or null if no such
+ */
+ private Entry getEntryAfterMiss(ThreadLocal key, int i, Entry e) {
+ Entry[] tab = table;
+ int len = tab.length;
+
+ while (e != null) {
+ ThreadLocal k = e.get();
+ if (k == key)
+ return e;
+ if (k == null)
+ expungeStaleEntry(i);
+ else
+ i = nextIndex(i, len);
+ e = tab[i];
+ }
+ return null;
+ }
+
+ /**
+ * Set the value associated with key.
+ *
+ * @param key the thread local object
+ * @param value the value to be set
+ */
+ private void set(ThreadLocal key, Object value) {
+
+ // We don't use a fast path as with get() because it is at
+ // least as common to use set() to create new entries as
+ // it is to replace existing ones, in which case, a fast
+ // path would fail more often than not.
+
+ Entry[] tab = table;
+ int len = tab.length;
+ int i = key.threadLocalHashCode & (len-1);
+
+ for (Entry e = tab[i];
+ e != null;
+ e = tab[i = nextIndex(i, len)]) {
+ ThreadLocal k = e.get();
+
+ if (k == key) {
+ e.value = value;
+ return;
+ }
+
+ if (k == null) {
+ replaceStaleEntry(key, value, i);
+ return;
+ }
+ }
+
+ tab[i] = new Entry(key, value);
+ int sz = ++size;
+ if (!cleanSomeSlots(i, sz) && sz >= threshold)
+ rehash();
+ }
+
+ /**
+ * Remove the entry for key.
+ */
+ private void remove(ThreadLocal key) {
+ Entry[] tab = table;
+ int len = tab.length;
+ int i = key.threadLocalHashCode & (len-1);
+ for (Entry e = tab[i];
+ e != null;
+ e = tab[i = nextIndex(i, len)]) {
+ if (e.get() == key) {
+ e.clear();
+ expungeStaleEntry(i);
+ return;
+ }
+ }
+ }
+
+ /**
+ * Replace a stale entry encountered during a set operation
+ * with an entry for the specified key. The value passed in
+ * the value parameter is stored in the entry, whether or not
+ * an entry already exists for the specified key.
+ *
+ * As a side effect, this method expunges all stale entries in the
+ * "run" containing the stale entry. (A run is a sequence of entries
+ * between two null slots.)
+ *
+ * @param key the key
+ * @param value the value to be associated with key
+ * @param staleSlot index of the first stale entry encountered while
+ * searching for key.
+ */
+ private void replaceStaleEntry(ThreadLocal key, Object value,
+ int staleSlot) {
+ Entry[] tab = table;
+ int len = tab.length;
+ Entry e;
+
+ // Back up to check for prior stale entry in current run.
+ // We clean out whole runs at a time to avoid continual
+ // incremental rehashing due to garbage collector freeing
+ // up refs in bunches (i.e., whenever the collector runs).
+ int slotToExpunge = staleSlot;
+ for (int i = prevIndex(staleSlot, len);
+ (e = tab[i]) != null;
+ i = prevIndex(i, len))
+ if (e.get() == null)
+ slotToExpunge = i;
+
+ // Find either the key or trailing null slot of run, whichever
+ // occurs first
+ for (int i = nextIndex(staleSlot, len);
+ (e = tab[i]) != null;
+ i = nextIndex(i, len)) {
+ ThreadLocal k = e.get();
+
+ // If we find key, then we need to swap it
+ // with the stale entry to maintain hash table order.
+ // The newly stale slot, or any other stale slot
+ // encountered above it, can then be sent to expungeStaleEntry
+ // to remove or rehash all of the other entries in run.
+ if (k == key) {
+ e.value = value;
+
+ tab[i] = tab[staleSlot];
+ tab[staleSlot] = e;
+
+ // Start expunge at preceding stale entry if it exists
+ if (slotToExpunge == staleSlot)
+ slotToExpunge = i;
+ cleanSomeSlots(expungeStaleEntry(slotToExpunge), len);
+ return;
+ }
+
+ // If we didn't find stale entry on backward scan, the
+ // first stale entry seen while scanning for key is the
+ // first still present in the run.
+ if (k == null && slotToExpunge == staleSlot)
+ slotToExpunge = i;
+ }
+
+ // If key not found, put new entry in stale slot
+ tab[staleSlot].value = null;
+ tab[staleSlot] = new Entry(key, value);
+
+ // If there are any other stale entries in run, expunge them
+ if (slotToExpunge != staleSlot)
+ cleanSomeSlots(expungeStaleEntry(slotToExpunge), len);
+ }
+
+ /**
+ * Expunge a stale entry by rehashing any possibly colliding entries
+ * lying between staleSlot and the next null slot. This also expunges
+ * any other stale entries encountered before the trailing null. See
+ * Knuth, Section 6.4
+ *
+ * @param staleSlot index of slot known to have null key
+ * @return the index of the next null slot after staleSlot
+ * (all between staleSlot and this slot will have been checked
+ * for expunging).
+ */
+ private int expungeStaleEntry(int staleSlot) {
+ Entry[] tab = table;
+ int len = tab.length;
+
+ // expunge entry at staleSlot
+ tab[staleSlot].value = null;
+ tab[staleSlot] = null;
+ size--;
+
+ // Rehash until we encounter null
+ Entry e;
+ int i;
+ for (i = nextIndex(staleSlot, len);
+ (e = tab[i]) != null;
+ i = nextIndex(i, len)) {
+ ThreadLocal k = e.get();
+ if (k == null) {
+ e.value = null;
+ tab[i] = null;
+ size--;
+ } else {
+ int h = k.threadLocalHashCode & (len - 1);
+ if (h != i) {
+ tab[i] = null;
+
+ // Unlike Knuth 6.4 Algorithm R, we must scan until
+ // null because multiple entries could have been stale.
+ while (tab[h] != null)
+ h = nextIndex(h, len);
+ tab[h] = e;
+ }
+ }
+ }
+ return i;
+ }
+
+ /**
+ * Heuristically scan some cells looking for stale entries.
+ * This is invoked when either a new element is added, or
+ * another stale one has been expunged. It performs a
+ * logarithmic number of scans, as a balance between no
+ * scanning (fast but retains garbage) and a number of scans
+ * proportional to number of elements, that would find all
+ * garbage but would cause some insertions to take O(n) time.
+ *
+ * @param i a position known NOT to hold a stale entry. The
+ * scan starts at the element after i.
+ *
+ * @param n scan control: <tt>log2(n)</tt> cells are scanned,
+ * unless a stale entry is found, in which case
+ * <tt>log2(table.length)-1</tt> additional cells are scanned.
+ * When called from insertions, this parameter is the number
+ * of elements, but when from replaceStaleEntry, it is the
+ * table length. (Note: all this could be changed to be either
+ * more or less aggressive by weighting n instead of just
+ * using straight log n. But this version is simple, fast, and
+ * seems to work well.)
+ *
+ * @return true if any stale entries have been removed.
+ */
+ private boolean cleanSomeSlots(int i, int n) {
+ boolean removed = false;
+ Entry[] tab = table;
+ int len = tab.length;
+ do {
+ i = nextIndex(i, len);
+ Entry e = tab[i];
+ if (e != null && e.get() == null) {
+ n = len;
+ removed = true;
+ i = expungeStaleEntry(i);
+ }
+ } while ( (n >>>= 1) != 0);
+ return removed;
+ }
+
+ /**
+ * Re-pack and/or re-size the table. First scan the entire
+ * table removing stale entries. If this doesn't sufficiently
+ * shrink the size of the table, double the table size.
+ */
+ private void rehash() {
+ expungeStaleEntries();
+
+ // Use lower threshold for doubling to avoid hysteresis
+ if (size >= threshold - threshold / 4)
+ resize();
+ }
+
+ /**
+ * Double the capacity of the table.
+ */
+ private void resize() {
+ Entry[] oldTab = table;
+ int oldLen = oldTab.length;
+ int newLen = oldLen * 2;
+ Entry[] newTab = new Entry[newLen];
+ int count = 0;
+
+ for (int j = 0; j < oldLen; ++j) {
+ Entry e = oldTab[j];
+ if (e != null) {
+ ThreadLocal k = e.get();
+ if (k == null) {
+ e.value = null; // Help the GC
+ } else {
+ int h = k.threadLocalHashCode & (newLen - 1);
+ while (newTab[h] != null)
+ h = nextIndex(h, newLen);
+ newTab[h] = e;
+ count++;
+ }
+ }
+ }
+
+ setThreshold(newLen);
+ size = count;
+ table = newTab;
+ }
+
+ /**
+ * Expunge all stale entries in the table.
+ */
+ private void expungeStaleEntries() {
+ Entry[] tab = table;
+ int len = tab.length;
+ for (int j = 0; j < len; j++) {
+ Entry e = tab[j];
+ if (e != null && e.get() == null)
+ expungeStaleEntry(j);
+ }
+ }
+ }
+}
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