code: /**
  Copyright (c) 2007-2013 Alysson Bessani, Eduardo Alchieri, Paulo Sousa, and the authors indicated in the @author tags
  
  Licensed 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 bftsmart.tom.leaderchange;
  
  import java.io.IOException;
  import java.io.ObjectInput;
  import java.io.ObjectOutput;
  
  import bftsmart.communication.SystemMessage;
  import bftsmart.tom.util.TOMUtil;
  
  /**
   * Message used during leader change and synchronization
   * @author Joao Sousa
   */
  public class LCMessage extends SystemMessage {
  
      private int type;
      private int ts;
      private byte[] payload;
      public final boolean TRIGGER_LC_LOCALLY; // indicates that the replica should
                                               // initiate the LC protocol locally
  
      /**
       * Empty constructor
       */
      public LCMessage(){
      
          this.TRIGGER_LC_LOCALLY = false;
      }
  
  
      /**
       * Constructor
       * @param from replica that creates this message
       * @param type type of the message (STOP, SYNC, CATCH-UP)
       * @param ts timestamp of leader change and synchronization
       * @param payload dada that comes with the message
       */
      public LCMessage(int from, int type, int ts, byte[] payload) {
          super(from);
          this.type = type;
          this.ts = ts;
          this.payload = payload == null ? new byte[0] : payload;
          if (type == TOMUtil.TRIGGER_LC_LOCALLY && from == -1) this.TRIGGER_LC_LOCALLY = true;
          else this.TRIGGER_LC_LOCALLY  = false;
      }
  
      /**
       * Get type of message
       * @return type of message
       */
      public int getType() {
          return type;
      }
  
      /**
       * Get timestamp of leader change and synchronization
       * @return timestamp of leader change and synchronization
       */
      public int getReg() {
          return ts;
      }
  
      /**
       * Obter data of the message
       * @return data of the message
       */
      public byte[] getPayload() {
          return payload;
      }
  
      @Override
      public void writeExternal(ObjectOutput out) throws IOException{
          super.writeExternal(out);
  
          out.writeInt(type);
          out.writeInt(ts);
          out.writeObject(payload);
      }
  
      @Override
      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException{
          super.readExternal(in);
  
          type = in.readInt();
          ts = in.readInt();
          payload = (byte[]) in.readObject();
      }
  }
  