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

"FreePastry" Peer-to-Peer Application Development Substrate

Copyright 2002-2007, Rice University. Copyright 2006-2007, Max Planck Institute 
for Software Systems.  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), Max Planck Institute for Software 
Systems (MPI-SWS) 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, MPI-SWS 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, MPI-SWS 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.*;

import java.lang.Comparable;

import rice.p2p.commonapi.rawserialization.*;

/**
 * @(#) Id.java This interface is an abstraction of an Id (or key) from the CommonAPI paper.
 *
 * @version $Id: Id.java 3613 2007-02-15 14:45:14Z jstewart $
 * @author Alan Mislove
 * @author Peter Druschel
 */
public interface Id extends Comparable, Serializable {

  /**
   * Checks if this Id is between two given ids ccw (inclusive) and cw (exclusive) on the circle
   *
   * @param ccw the counterclockwise id
   * @param cw the clockwise id
   * @return true if this is between ccw (inclusive) and cw (exclusive), false otherwise
   */
  public boolean isBetween(Id ccw, Id cw);

  /**
   * Checks to see if the Id nid is clockwise or counterclockwise from this, on the ring. An Id is
   * clockwise if it is within the half circle clockwise from this on the ring. An Id is considered
   * counter-clockwise from itself.
   *
   * @param nid The id to compare to
   * @return true if clockwise, false otherwise.
   */
  public boolean clockwise(Id nid);

  /**
   * Returns an Id corresponding to this Id plus a given distance
   *
   * @param offset the distance to add
   * @return the new Id
   */
  public Id addToId(Distance offset);

  /**
   * Returns the shorter numerical distance on the ring between a pair of Ids.
   *
   * @param nid the other node id.
   * @return the distance between this and nid.
   */
  public Distance distanceFromId(Id nid);

  /**
   * Returns the longer numerical distance on the ring between a pair of Ids.
   *
   * @param nid the other node id.
   * @return the distance between this and nid.
   */
  public Distance longDistanceFromId(Id nid);

  /**
   * A class for representing and manipulating the distance between two Ids on the circle.
   *
   * @version $Id: Id.java 3613 2007-02-15 14:45:14Z jstewart $
   * @author amislove
   */
  public static interface Distance extends Comparable, Serializable {

    /**
     * Shift operator. shift(-1,0) multiplies value of this by two, shift(1,0) divides by 2
     *
     * @param cnt the number of bits to shift, negative shifts left, positive shifts right
     * @param fill value of bit shifted in (0 if fill == 0, 1 otherwise)
     * @return this
     */
    public Distance shiftDistance(int cnt, int fill);
  }

  /**
   * Returns a (mutable) byte array representing this Id
   *
   * @return A byte[] representing this Id
   */
  public byte[] toByteArray();
  
  /**
   * Stores the byte[] value of this Id in the provided byte array
   *
   * @return A byte[] representing this Id
   */
  public void toByteArray(byte[] array, int offset);
  
  /**
   * Returns the length of the byte[] representing this Id
   *
   * @return The length of the byte[] representing this Id
   */
  public int getByteArrayLength();

  /**
   * Returns a string representing the full length of this Id.
   *
   * @return A string with all of this Id
   */
  public String toStringFull();
  
  /**
   * Serialize
   * @param buf
   * @throws IOException
   */
  public void serialize(OutputBuffer buf) throws IOException;

  public short getType();
  
}

