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

"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
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- Redistributions in binary form must reproduce the above copyright
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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
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********************************************************************************/

package rice.p2p.past.gc;

import rice.p2p.commonapi.*;
import rice.p2p.util.*;

/**
 * @(#) GCId.java This class is the internal representation of an Id with an
 * expiration time in the GC Past system. Should not be used by applications.
 *
 * @version $Id: GCId.java 2302 2005-03-11 00:58:26Z jeffh $
 * @author Alan Mislove
 */
public class GCId implements Id {

  /**
   * The id which this ringId represents
   */
  protected Id id;

  /**
   * The ringId which this ringId represents
   */
  protected long expiration;

  /**
   * Constructor
   *
   * @param id DESCRIBE THE PARAMETER
   * @param expiration DESCRIBE THE PARAMETER
   */
  public GCId(Id id, long expiration) {
    this.id = id;
    this.expiration = expiration;
  }

  /**
   * Returns this gcid's id
   *
   * @return The id of this ringid
   */
  public Id getId() {
    return id;
  }

  /**
   * Returns this gcid's expiration time
   *
   * @return The expiration time of this gcid
   */
  public long getExpiration() {
    return expiration;
  }

  /**
   * 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) {
    return id.isBetween(((GCId) ccw).getId(), ((GCId) cw).getId());
  }

  /**
   * Returns the length of the byte[] representing this Id
   *
   * @return The length of the byte[] representing this Id
   */
  public int getByteArrayLength() {
    return id.getByteArrayLength() + 8;
  }

  /**
   * 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) {
    return id.clockwise(((GCId) nid).getId());
  }

  /**
   * 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) {
    return new GCId(id.addToId(offset), expiration);
  }

  /**
   * 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) {
    return id.distanceFromId(((GCId) nid).getId());
  }

  /**
   * 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) {
    return id.longDistanceFromId(((GCId) nid).getId());
  }

  /**
   * Returns a (mutable) byte array representing this Id
   *
   * @return A byte[] representing this Id
   */
  public byte[] toByteArray() {
    byte[] result = new byte[getByteArrayLength()];

    toByteArray(result, 0);

    return result;
  }

  /**
   * Stores the byte[] value of this Id in the provided byte array
   *
   * @param array DESCRIBE THE PARAMETER
   * @param offset DESCRIBE THE PARAMETER
   */
  public void toByteArray(byte[] array, int offset) {
    id.toByteArray(array, offset);
    MathUtils.longToByteArray(expiration, array, offset + id.getByteArrayLength());
  }

  /**
   * Returns whether or not this object is equal to the provided one
   *
   * @param o The object to compare to
   * @return Whether or not this is object is equal
   */
  public boolean equals(Object o) {
    if (!(o instanceof GCId)) {
      return false;
    }

    return (((GCId) o).id.equals(id) && (((GCId) o).expiration == expiration));
  }

  /**
   * Returns the hashCode
   *
   * @return hashCode
   */
  public int hashCode() {
    return id.hashCode();
  }

  /**
   * Returns a string representing this ring Id.
   *
   * @return A string with all of this Id
   */
  public String toString() {
    return id + "-" + expiration;
  }

  /**
   * Returns a string representing the full length of this Id.
   *
   * @return A string with all of this Id
   */
  public String toStringFull() {
    return id.toStringFull() + "-" + expiration;
  }

  /**
   * Returns this id compared to the target
   *
   * @param o DESCRIBE THE PARAMETER
   * @return The comparison
   */
  public int compareTo(Object o) {
    return id.compareTo(((GCId) o).id);
  }
}


