001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.log4j.helpers; 019 020import java.util.Hashtable; 021 022/** 023 <code>ThreadLocalMap</code> extends {@link InheritableThreadLocal} 024 to bequeath a copy of the hashtable of the MDC of the parent 025 thread. 026 027 @author Ceki Gülcü 028 @since 1.2 029*/ 030final public class ThreadLocalMap extends InheritableThreadLocal { 031 032 public 033 final 034 Object childValue(Object parentValue) { 035 Hashtable ht = (Hashtable) parentValue; 036 if(ht != null) { 037 return ht.clone(); 038 } else { 039 return null; 040 } 041 } 042}