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

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

- Neither  the name  of Rice  University (RICE) nor  the names  of its
contributors may be  used to endorse or promote  products derived from
this software without specific prior written permission.

This software is provided by RICE and the contributors on an "as is"
basis, without any representations or warranties of any kind, express
or implied including, but not limited to, representations or
warranties of non-infringement, merchantability or fitness for a
particular purpose. In no event shall RICE or contributors be liable
for any direct, indirect, incidental, special, exemplary, or
consequential damages (including, but not limited to, procurement of
substitute goods or services; loss of use, data, or profits; or
business interruption) however caused and on any theory of liability,
whether in contract, strict liability, or tort (including negligence
or otherwise) arising in any way out of the use of this software, even
if advised of the possibility of such damage.

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

package rice.p2p.commonapi;

import java.io.*;

/**
 * @(#) Message.java This interface is an abstraction of a message which is sent
 * through the common API-based system.
 *
 * @version $Id: Message.java 2302 2005-03-11 00:58:26Z jeffh $
 * @author Alan Mislove
 * @author Peter Druschel
 */
public interface Message extends Serializable {

  // different priority levels
  /**
   * DESCRIBE THE FIELD
   */
  public final static int HIGH_PRIORITY = 5;
  /**
   * DESCRIBE THE FIELD
   */
  public final static int MEDIUM_HIGH_PRIORITY = 10;
  /**
   * DESCRIBE THE FIELD
   */
  public final static int MEDIUM_PRIORITY = 15;
  /**
   * DESCRIBE THE FIELD
   */
  public final static int MEDIUM_LOW_PRIORITY = 20;
  /**
   * DESCRIBE THE FIELD
   */
  public final static int LOW_PRIORITY = 25;

  /**
   * Method which should return the priority level of this message. The messages
   * can range in priority from 0 (highest priority) to Integer.MAX_VALUE
   * (lowest) - when sending messages across the wire, the queue is sorted by
   * message priority. If the queue reaches its limit, the lowest priority
   * messages are discarded. Thus, applications which are very verbose should
   * have LOW_PRIORITY or lower, and applications which are somewhat quiet are
   * allowed to have MEDIUM_PRIORITY or possibly even HIGH_PRIORITY.
   *
   * @return This message's priority
   */
  public int getPriority();

}

