| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package java.lang; |
| |
| |
| /** |
| * A thread-local variable whose value is passed from parent to child thread. By |
| * default, the value of an inheritable thread-local variable of a child thread |
| * is initialized with the value of the parent thread's variable at thread |
| * creation time. However, subclasses may override {code #childValue(Object)} |
| * to provide an arbitrary function for passing the value of a parent's |
| * thread-local variable to the child's thread-local variable. |
| * |
| * @see java.lang.Thread |
| * @see java.lang.ThreadLocal |
| */ |
| public class InheritableThreadLocal<T> extends ThreadLocal<T> { |
| |
| /** |
| * Creates a new inheritable thread-local variable. |
| */ |
| public InheritableThreadLocal() { |
| } |
| |
| /** |
| * Computes the initial value of this thread-local variable for the child |
| * thread given the parent thread's value. Called from the parent thread when |
| * creating a child thread. The default implementation returns the parent |
| * thread's value. |
| * |
| * @param parentValue the value of the variable in the parent thread. |
| * @return the initial value of the variable for the child thread. |
| */ |
| protected T childValue(T parentValue) { |
| return parentValue; |
| } |
| |
| @Override |
| Values values(Thread current) { |
| return current.inheritableValues; |
| } |
| |
| @Override |
| Values initializeValues(Thread current) { |
| return current.inheritableValues = new Values(); |
| } |
| } |