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;
  
  /**
   * Throws an exception if packets are dropped causing the transport to be
   * closed.
   * 
   * 
   */
  public class ExceptionIfDroppedReplayStrategy implements ReplayStrategy {
  
      private int maximumDifference = 5;
  
      public ExceptionIfDroppedReplayStrategy() {
      }
  
      public ExceptionIfDroppedReplayStrategy(int maximumDifference) {
          this.maximumDifference = maximumDifference;
      }
  
      public boolean onDroppedPackets(ReliableTransport transport, int expectedCounter, int actualCounter, int nextAvailableCounter) throws IOException {
          int difference = actualCounter - expectedCounter;
          long count = Math.abs(difference);
          if (count > maximumDifference) {
              throw new IOException("Packets dropped on: " + transport + " count: " + count + " expected: " + expectedCounter + " but was: " + actualCounter);
          }
  
          // lets discard old commands
          return difference > 0;
      }
  
      public void onReceivedPacket(ReliableTransport transport, long expectedCounter) {
      }
  
      public int getMaximumDifference() {
          return maximumDifference;
      }
  
      /**
       * Sets the maximum allowed difference between an expected packet and an
       * actual packet before an error occurs
       */
      public void setMaximumDifference(int maximumDifference) {
          this.maximumDifference = maximumDifference;
      }
  
  }
  