/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software License
 * version 1.1, a copy of which has been included  with this distribution in
 * the LICENSE.txt file.
 */

package org.apache.log4j.helpers;

import java.util.Hashtable;

/**
   <code>ThreadLocalMap</code> extends {@link InheritableThreadLocal}
   to bequeath a copy of the hashtable of the MDC of the parent
   thread.

   @author Ceki G&uuml;lc&uuml;
   @since 1.2
*/
final public class ThreadLocalMap extends InheritableThreadLocal {

  public final Object childValue(Object parentValue) {
    Hashtable ht = (Hashtable) parentValue;
    if(ht != null) {
      return ht.clone();
    } else {
      return null;
    }
  }
}