/*
    * 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 org.apache.log4j;
  
  import java.util.HashMap;
  import java.util.Hashtable;
  import java.util.Map;
  
  import org.apache.logging.log4j.ThreadContext;
  
  /**
   * This class behaves just like Log4j's MDC would - and so can cause issues with the redeployment of web
   * applications if the Objects stored in the threads Map cannot be garbage collected.
   */
  public final class MDC {
  
  
      private static ThreadLocal<Map<String, Object>> localMap =
          new InheritableThreadLocal<Map<String, Object>>() {
              @Override
              protected Map<String, Object> initialValue() {
                  return new HashMap<String, Object>();
              }
  
              @Override
              protected Map<String, Object> childValue(final Map<String, Object> parentValue) {
                  return parentValue == null ? new HashMap<String, Object>() : new HashMap<String, Object>(parentValue);
              }
          };
  
      private MDC() {
      }
  
  
      public static void put(final String key, final String value) {
          localMap.get().put(key, value);
          ThreadContext.put(key, value);
      }
  
  
      public static void put(final String key, final Object value) {
          localMap.get().put(key, value);
          ThreadContext.put(key, value.toString());
      }
  
      public static Object get(final String key) {
          return localMap.get().get(key);
      }
  
      public static void remove(final String key) {
          localMap.get().remove(key);
          ThreadContext.remove(key);
      }
  
      public static void clear() {
          localMap.get().clear();
          ThreadContext.clearMap();
      }
  
      public static Hashtable<String, Object> getContext() {
          return new Hashtable<String, Object>(localMap.get());
      }
  }