contenthashpastcontenthandle.java

pastry的java实现的2.0b版

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

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

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package rice.p2p.past;

import java.io.*;

import rice.*;
import rice.p2p.commonapi.*;
import rice.p2p.commonapi.rawserialization.*;
import rice.p2p.past.rawserialization.RawPastContentHandle;

/**
 * @(#) ContentHashPastContentHandle.java A handle class for content-hash
 * objects stored in Past.
 *
 * @version $Id: ContentHashPastContentHandle.java 3274 2006-05-15 16:17:47Z
 *      jeffh $
 * @author Peter Druschel
 */
public class ContentHashPastContentHandle implements RawPastContentHandle {

  // the node on which the content object resides
  private NodeHandle storageNode;

  // the object's id
  private Id myId;
  /**
   * DESCRIBE THE FIELD
   */
  public final static short TYPE = -12;

  /**
   * Constructor
   *
   * @param nh The handle of the node which holds the object
   * @param id key identifying the object to be inserted
   */
  public ContentHashPastContentHandle(NodeHandle nh, Id id) {
    storageNode = nh;
    myId = id;
  }

  /**
   * Constructor for ContentHashPastContentHandle.
   *
   * @param buf DESCRIBE THE PARAMETER
   * @param endpoint DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public ContentHashPastContentHandle(InputBuffer buf, Endpoint endpoint) throws IOException {
    myId = endpoint.readId(buf, buf.readShort());
    storageNode = endpoint.readNodeHandle(buf);
  }


  // ----- PastCONTENTHANDLE METHODS -----

  /**
   * Returns the id of the PastContent object associated with this handle
   *
   * @return the id
   */
  public Id getId() {
    return myId;
  }

  /**
   * Returns the NodeHandle of the Past node on which the object associated with
   * this handle is stored
   *
   * @return the id
   */
  public NodeHandle getNodeHandle() {
    return storageNode;
  }

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

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public void serialize(OutputBuffer buf) throws IOException {
    buf.writeShort(myId.getType());
    myId.serialize(buf);
    storageNode.serialize(buf);
  }
}