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.transport.reliable;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * 
   * 
   */
  public class DefaultReplayBuffer implements ReplayBuffer {
  
      private static final Logger LOG = LoggerFactory.getLogger(DefaultReplayBuffer.class);
  
      private final int size;
      private ReplayBufferListener listener;
      private Map<Integer, Object> map;
      private int lowestCommandId = 1;
      private Object lock = new Object();
  
      public DefaultReplayBuffer(int size) {
          this.size = size;
          map = createMap(size);
      }
  
      public void addBuffer(int commandId, Object buffer) {
          if (LOG.isDebugEnabled()) {
              LOG.debug("Adding command ID: " + commandId + " to replay buffer: " + this + " object: " + buffer);
          }
          synchronized (lock) {
              int max = size - 1;
              while (map.size() >= max) {
                  // lets find things to evict
                  Object evictedBuffer = map.remove(++lowestCommandId);
                  onEvictedBuffer(lowestCommandId, evictedBuffer);
              }
              map.put(commandId, buffer);
          }
      }
  
      public void setReplayBufferListener(ReplayBufferListener bufferPoolAdapter) {
          this.listener = bufferPoolAdapter;
      }
  
      public void replayMessages(int fromCommandId, int toCommandId, Replayer replayer) throws IOException {
          if (replayer == null) {
              throw new IllegalArgumentException("No Replayer parameter specified");
          }
          if (LOG.isDebugEnabled()) {
              LOG.debug("Buffer: " + this + " replaying messages from: " + fromCommandId + " to: " + toCommandId);
          }
          for (int i = fromCommandId; i <= toCommandId; i++) {
              Object buffer = null;
              synchronized (lock) {
                  buffer = map.get(i);
              }
              replayer.sendBuffer(i, buffer);
          }
      }
  
      protected Map<Integer, Object> createMap(int maximumSize) {
          return new HashMap<Integer, Object>(maximumSize);
      }
  
      protected void onEvictedBuffer(int commandId, Object buffer) {
          if (listener != null) {
              listener.onBufferDiscarded(commandId, buffer);
          }
      }
  }
  