id.java

pastry的java实现的2.0b版

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"FreePastry" Peer-to-Peer Application Development Substrate 

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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 3274 2006-05-15 16:17:47Z jeffh $
 * @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 3274 2006-05-15 16:17:47Z jeffh $
   * @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
   *
   * @param array DESCRIBE THE PARAMETER
   * @param offset DESCRIBE THE PARAMETER
   */
  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;

  /**
   * Gets the Type attribute of the Id object
   *
   * @return The Type value
   */
  public short getType();

}