content: /**
   * 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.activemq.broker.region.group;
  
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  import org.apache.activemq.broker.region.Destination;
  import org.apache.activemq.broker.region.Subscription;
  import org.apache.activemq.command.ConsumerId;
  import org.apache.activemq.memory.LRUMap;
  
  /**
   * A simple implementation which tracks every individual GroupID value in a LRUCache
   * 
   * 
   */
  public class CachedMessageGroupMap implements MessageGroupMap {
      private final LRUMap<String, ConsumerId> cache;
      private final int maximumCacheSize;
      Destination destination;
  
      CachedMessageGroupMap(int size){
        cache = new LRUMap<String, ConsumerId>(size) {
            @Override
            public boolean removeEldestEntry(final Map.Entry eldest) {
                boolean remove = super.removeEldestEntry(eldest);
                if (remove) {
                    if (destination != null) {
                        for (Subscription s : destination.getConsumers()) {
                          if (s.getConsumerInfo().getConsumerId().equals(eldest.getValue())) {
                              s.getConsumerInfo().decrementAssignedGroupCount(destination.getActiveMQDestination());
                              break;
                            }
                        }
                    }
                }
                return remove;
            }
        };
        maximumCacheSize = size;
      }
      public synchronized void put(String groupId, ConsumerId consumerId) {
          cache.put(groupId, consumerId);
      }
  
      public synchronized ConsumerId get(String groupId) {
          return cache.get(groupId);
      }
  
      public synchronized ConsumerId removeGroup(String groupId) {
          return cache.remove(groupId);
      }
  
      public synchronized MessageGroupSet removeConsumer(ConsumerId consumerId) {
          SimpleMessageGroupSet ownedGroups = new SimpleMessageGroupSet();
          Map<String,ConsumerId> map = new HashMap<String, ConsumerId>();
          map.putAll(cache);
          for (Iterator<String> iter = map.keySet().iterator(); iter.hasNext();) {
              String group = iter.next();
              ConsumerId owner = map.get(group);
              if (owner.equals(consumerId)) {
                  ownedGroups.add(group);
              }
          }
          for (String group:ownedGroups.getUnderlyingSet()){
              cache.remove(group);
          }
          return ownedGroups;
      }
  
  
      @Override
      public synchronized void removeAll(){
          cache.clear();
          if (destination != null) {
              for (Subscription s : destination.getConsumers()) {
                  s.getConsumerInfo().clearAssignedGroupCount(destination.getActiveMQDestination());
              }
          }
      }
  
      @Override
      public synchronized Map<String, String> getGroups() {
          Map<String,String> result = new HashMap<String,String>();
          for (Map.Entry<String,ConsumerId>entry: cache.entrySet()){
              result.put(entry.getKey(),entry.getValue().toString());
          }
          return result;
      }
  
      @Override
      public String getType() {
          return "cached";
      }
  
      public int getMaximumCacheSize(){
          return maximumCacheSize;
      }
  
      public String toString() {
          return "message groups: " + cache.size();
      }
  
      public void setDestination(Destination destination) {
          this.destination = destination;
      }
  }
  