--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/lang/InheritableThreadLocal.java	Sat Dec 01 00:00:00 2007 +0000
@@ -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);
+    }
+}