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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2005-2014 Red Hat, Inc.
 * Red Hat 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.hornetq.utils;

import java.util.AbstractSet;
import java.util.Iterator;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 *
 * A ConcurrentHashSet.
 *
 * Offers same concurrency as ConcurrentHashMap but for a Set
 *
 * @author Tim Fox
 * @version $Revision: 1935 $
 *
 */
public class ConcurrentHashSet extends AbstractSet implements ConcurrentSet
{
   private final ConcurrentMap theMap;

   private static final Object dummy = new Object();

   public ConcurrentHashSet()
   {
      theMap = new ConcurrentHashMap();
   }

   @Override
   public int size()
   {
      return theMap.size();
   }

   @Override
   public Iterator iterator()
   {
      return theMap.keySet().iterator();
   }

   @Override
   public boolean isEmpty()
   {
      return theMap.isEmpty();
   }

   @Override
   public boolean add(final E o)
   {
      return theMap.put(o, ConcurrentHashSet.dummy) == null;
   }

   @Override
   public boolean contains(final Object o)
   {
      return theMap.containsKey(o);
   }

   @Override
   public void clear()
   {
      theMap.clear();
   }

   @Override
   public boolean remove(final Object o)
   {
      return theMap.remove(o) == ConcurrentHashSet.dummy;
   }

   public boolean addIfAbsent(final E o)
   {
      Object obj = theMap.putIfAbsent(o, ConcurrentHashSet.dummy);

      return obj == null;
   }

}