diff -r fd16c54261b3 -r 90ce3da70b43 jdk/src/share/classes/java/lang/InheritableThreadLocal.java --- /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 ThreadLocal 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 childValue + * method in this class. + * + *
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
+ * 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);
+ }
+}