fragmentkey.java

pastry的java实现的2.0b版

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

"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
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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.glacier;

import java.io.IOException;

import rice.p2p.commonapi.*;
import rice.p2p.commonapi.rawserialization.*;
import rice.p2p.glacier.VersionKey;
import rice.p2p.util.MathUtils;

/**
 * DESCRIBE THE CLASS
 *
 * @version $Id: FragmentKey.java 3274 2006-05-15 16:17:47Z jeffh $
 * @author ahae
 */
public class FragmentKey implements Id, Comparable {

  /**
   * DESCRIBE THE FIELD
   */
  protected VersionKey key;
  /**
   * DESCRIBE THE FIELD
   */
  protected int id;
  /**
   * DESCRIBE THE FIELD
   */
  public final static short TYPE = 42;

  private final static long serialVersionUID = 5373228569261524536L;

  /**
   * Constructor for FragmentKey.
   *
   * @param key DESCRIBE THE PARAMETER
   * @param id DESCRIBE THE PARAMETER
   */
  public FragmentKey(VersionKey key, int id) {
    this.id = id;
    this.key = key;
  }

  /**
   * Constructor for FragmentKey.
   *
   * @param buf DESCRIBE THE PARAMETER
   * @param endpoint DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public FragmentKey(InputBuffer buf, Endpoint endpoint) throws IOException {
    id = buf.readInt();
    key = new VersionKey(buf, endpoint);
  }

  /**
   * Gets the Between attribute of the FragmentKey object
   *
   * @param ccw DESCRIBE THE PARAMETER
   * @param cw DESCRIBE THE PARAMETER
   * @return The Between value
   */
  public boolean isBetween(Id ccw, Id cw) {
    throw new RuntimeException("FragmentKey.isBetween() is not supported!");
  }

  /**
   * Gets the VersionKey attribute of the FragmentKey object
   *
   * @return The VersionKey value
   */
  public VersionKey getVersionKey() {
    return key;
  }

  /**
   * Gets the FragmentID attribute of the FragmentKey object
   *
   * @return The FragmentID value
   */
  public int getFragmentID() {
    return id;
  }

  /**
   * Gets the PeerKey attribute of the FragmentKey object
   *
   * @param otherId DESCRIBE THE PARAMETER
   * @return The PeerKey value
   */
  public FragmentKey getPeerKey(int otherId) {
    return new FragmentKey(key, otherId);
  }

  /**
   * Returns the length of the byte[] representing this Id
   *
   * @return The length of the byte[] representing this Id
   */
  public int getByteArrayLength() {
    return key.getByteArrayLength() + 4;
  }

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

  /**
   * DESCRIBE THE METHOD
   *
   * @param peer DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public boolean equals(Object peer) {
    if (!(peer instanceof FragmentKey)) {
      return false;
    }

    FragmentKey sk = (FragmentKey) peer;
    return (sk.key.equals(this.key) && (sk.id == this.id));
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  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 result DESCRIBE THE PARAMETER
   * @param offset DESCRIBE THE PARAMETER
   */
  public void toByteArray(byte[] result, int offset) {
    key.toByteArray(result, offset);
    MathUtils.intToByteArray(id, result, offset + key.getByteArrayLength());
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  public String toStringFull() {
    return key.toStringFull() + "#" + id;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  public String toString() {
    return key.toString() + "#" + id;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param nid DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public Distance longDistanceFromId(Id nid) {
    throw new RuntimeException("FragmentKey.longDistanceFromId() is not supported!");
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param nid DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public Distance distanceFromId(Id nid) {
    throw new RuntimeException("FragmentKey.distanceFromId() is not supported!");
  }

  /**
   * Adds a feature to the ToId attribute of the FragmentKey object
   *
   * @param offset The feature to be added to the ToId attribute
   * @return DESCRIBE THE RETURN VALUE
   */
  public Id addToId(Distance offset) {
    throw new RuntimeException("FragmentKey.addToId() is not supported!");
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param nid DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public boolean clockwise(Id nid) {
    throw new RuntimeException("FragmentKey.clockwise() is not supported!");
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param o DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public int compareTo(Object o) {
    int keyResult = key.compareTo(((FragmentKey) o).key);
    if (keyResult != 0) {
      return keyResult;
    }

    if (this.id < ((FragmentKey) o).id) {
      return -1;
    }
    if (this.id > ((FragmentKey) o).id) {
      return 1;
    }

    return 0;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  public int hashCode() {
    return (key.hashCode() + id);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public void serialize(OutputBuffer buf) throws IOException {
    buf.writeInt(id);
    key.serialize(buf);
//    throw new RuntimeException("FragmentKey.serialize() is not supported!");
  }
}