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    package org.apache.activemq.util;
018    
019    import org.slf4j.MDC;
020    
021    import java.util.Hashtable;
022    import java.util.Map;
023    
024    /**
025     *  Helper class as MDC Log4J adapter doesn't behave well with null values
026     */
027    public class MDCHelper {
028    
029        public static Map getCopyOfContextMap() {
030            Map map = MDC.getCopyOfContextMap();
031            if (map == null) {
032                map = new Hashtable();
033            }
034            return map;
035        }
036    
037        public static void setContextMap(Map map) {
038            if (map == null) {
039                map = new Hashtable();
040            }
041            MDC.setContextMap(map);
042        }
043    
044    }