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 */
017package org.apache.log4j;
018
019import java.util.HashMap;
020import java.util.Hashtable;
021import java.util.Map;
022
023import org.apache.logging.log4j.ThreadContext;
024
025/**
026 * This class behaves just like Log4j's MDC would - and so can cause issues with the redeployment of web
027 * applications if the Objects stored in the threads Map cannot be garbage collected.
028 */
029public final class MDC {
030
031    private static ThreadLocal<Map<String, Object>> localMap =
032        new InheritableThreadLocal<Map<String, Object>>() {
033            @Override
034            protected Map<String, Object> initialValue() {
035                return new HashMap<>();
036            }
037
038            @Override
039            protected Map<String, Object> childValue(final Map<String, Object> parentValue) {
040                return parentValue == null ? new HashMap<>() : new HashMap<>(parentValue);
041            }
042        };
043
044    private MDC() {
045    }
046
047
048    public static void put(final String key, final String value) {
049        localMap.get().put(key, value);
050        ThreadContext.put(key, value);
051    }
052
053
054    public static void put(final String key, final Object value) {
055        localMap.get().put(key, value);
056        ThreadContext.put(key, value.toString());
057    }
058
059    public static Object get(final String key) {
060        return localMap.get().get(key);
061    }
062
063    public static void remove(final String key) {
064        localMap.get().remove(key);
065        ThreadContext.remove(key);
066    }
067
068    public static void clear() {
069        localMap.get().clear();
070        ThreadContext.clearMap();
071    }
072
073    public static Hashtable<String, Object> getContext() {
074        return new Hashtable<>(localMap.get());
075    }
076}