messagelostmessage.java

pastry的java实现的2.0b版

/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

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- Redistributions in binary form must reproduce the above copyright
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- Neither  the name  of Rice  University (RICE) nor  the names  of its
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This software is provided by RICE and the contributors on an "as is"
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********************************************************************************/

package rice.p2p.past.messaging;

import java.io.IOException;

import rice.*;
import rice.environment.Environment;
import rice.environment.logging.Logger;
import rice.p2p.commonapi.*;
import rice.p2p.commonapi.rawserialization.*;
import rice.p2p.past.*;
import rice.p2p.util.JavaSerializedMessage;

/**
 * @(#) MessageLostMessage.java This class represents a reminder to Past that an
 * outstanding message exists, and that the waiting continuation should be
 * informed if the message is lost.
 *
 * @version $Id: MessageLostMessage.java 3274 2006-05-15 16:17:47Z jeffh $
 * @author Alan Mislove
 * @author Ansley Post
 * @author Peter Druschel
 */
public class MessageLostMessage extends PastMessage {

  // the id the message was sent to
  /**
   * DESCRIBE THE FIELD
   */
  protected Id id;

  // the hint the message was sent to
  /**
   * DESCRIBE THE FIELD
   */
  protected NodeHandle hint;

  // the message
  /**
   * DESCRIBE THE FIELD
   */
  protected String messageString;
  /**
   * DESCRIBE THE FIELD
   */
  public final static short TYPE = 7;

  private final static long serialVersionUID = -8664827144233122095L;

  /**
   * Constructor which takes a unique integer Id and the local id
   *
   * @param uid The unique id
   * @param local The local nodehandle
   * @param id DESCRIBE THE PARAMETER
   * @param message DESCRIBE THE PARAMETER
   * @param hint DESCRIBE THE PARAMETER
   */
  public MessageLostMessage(int uid, NodeHandle local, Id id, Message message, NodeHandle hint) {
    super(uid, local, local.getId());

    setResponse();
    this.hint = hint;
    if (message != null) {
      this.messageString = message.toString();
    } else {
      this.messageString = "";
    }
    this.id = id;
  }

  /**
   * Gets the Type attribute of the MessageLostMessage object
   *
   * @return The Type value
   */
  public short getType() {
    return TYPE;
  }

  /**
   * Method by which this message is supposed to return it's response - in this
   * case, it lets the continuation know that a the message was lost via the
   * receiveException method.
   *
   * @param c The continuation to return the reponse to.
   * @param env DESCRIBE THE PARAMETER
   * @param instance DESCRIBE THE PARAMETER
   */
  public void returnResponse(Continuation c, Environment env, String instance) {
    Logger logger = env.getLogManager().getLogger(getClass(), instance);
    Exception e = new PastException("Outgoing message '" + messageString + "' to " + id + "/" + hint + " was lost - please try again.");
    if (logger.level <= Logger.WARNING) {
      logger.logException("ERROR: Outgoing PAST message " + messageString + " with UID " + getUID() + " was lost", e);
    }
    c.receiveException(e);
  }

  /**
   * Returns a string representation of this message
   *
   * @return A string representing this message
   */
  public String toString() {
    return "[MessageLostMessage]";
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public void serialize(OutputBuffer buf) throws IOException {
    throw new RuntimeException("serialize() not supported in MessageLostMessage");
//    super.serialize(buf);
//
//    if (hint == null) {
//      buf.writeBoolean(false);
//    } else {
//      buf.writeBoolean(true);
//      hint.serialize(buf);
//    }
//
//    if (id == null) {
//      buf.writeBoolean(false);
//    } else {
//      buf.writeBoolean(true);
//      buf.writeShort(id.getType());
//      id.serialize(buf);
//    }
//
//    buf.writeUTF(messageString);
  }

//  public MessageLostMessage(InputBuffer buf, Endpoint endpoint) throws IOException {
//    super(buf, endpoint);
//
//    if (buf.readBoolean()) {
//      hint = endpoint.readNodeHandle(buf);
//    }
//    if (buf.readBoolean()) {
//      id = endpoint.readId(buf, buf.readShort());
//    }
//
//    messageString = buf.readUTF();
//  }
}