multiringendpoint.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.multiring;

import rice.*;

import java.io.IOException;
import java.util.*;

import rice.environment.Environment;
import rice.p2p.commonapi.*;
import rice.p2p.commonapi.appsocket.AppSocketReceiver;
import rice.p2p.commonapi.rawserialization.*;
import rice.p2p.multiring.messaging.RingMessage;
import rice.p2p.util.JavaSerializedMessage;

/**
 * @(#) MultiringEndpoint.java This class wraps an endpoint and allows for
 * applications to transparently use multiring functionality.
 *
 * @version $Id: MultiringEndpoint.java 3274 2006-05-15 16:17:47Z jeffh $
 * @author Alan Mislove
 */
public class MultiringEndpoint implements Endpoint {

  /**
   * The multiring node supporting this endpoint
   */
  protected MultiringNode node;

  /**
   * The application this endpoint is for
   */
  protected Application application;

  /**
   * The node which this mulitring node is wrapping
   */
  protected Endpoint endpoint;

//  protected MessageDeserializer myDeserializer;

  /**
   * Constructor
   *
   * @param node The node to base this node off of
   * @param endpoint DESCRIBE THE PARAMETER
   * @param application DESCRIBE THE PARAMETER
   */
  protected MultiringEndpoint(MultiringNode node, Endpoint endpoint, Application application) {
    this.node = node;
    this.endpoint = endpoint;
    this.application = application;
//    myDeserializer = endpoint.getDeserializer();
//    endpoint.setDeserializer(new MessageDeserializer() {
//
//      public Message deserialize(InputBuffer buf, short type, byte priority,
//          NodeHandle sender) throws IOException {
//        switch (type) {
//          case RingMessage.TYPE:
//            return new RingMessage(buf,MultiringEndpoint.this.endpoint,myDeserializer,sender,priority);
//        }
//        throw new IllegalArgumentException("Invalid type:"+type);
//      }
//
//    });
  }

  /**
   * Returns this node's id, which is its identifier in the namespace.
   *
   * @return The local node's id
   */
  public Id getId() {
    return RingId.build(node.getRingId(), endpoint.getId());
  }

  /**
   * Returns a handle to the local node below this endpoint. This node handle is
   * serializable, and can therefore be sent to other nodes in the network and
   * still be valid.
   *
   * @return A NodeHandle referring to the local node.
   */
  public NodeHandle getLocalNodeHandle() {
    return new MultiringNodeHandle(node.getRingId(), endpoint.getLocalNodeHandle());
  }

  /**
   * Returns a unique instance name of this endpoint, sort of a mailbox name for
   * this application.
   *
   * @return The unique instance name of this application
   */
  public String getInstance() {
    return "multiring" + endpoint.getInstance();
  }

  /*
   *  (non-Javadoc)
   *  @see rice.p2p.commonapi.Endpoint#getEnvironment()
   */
  /**
   * Gets the Environment attribute of the MultiringEndpoint object
   *
   * @return The Environment value
   */
  public Environment getEnvironment() {
    return node.getEnvironment();
  }

  /**
   * Gets the Deserializer attribute of the MultiringEndpoint object
   *
   * @return The Deserializer value
   */
  public MessageDeserializer getDeserializer() {
    return endpoint.getDeserializer();
  }

  /**
   * Sets the Deserializer attribute of the MultiringEndpoint object
   *
   * @param md The new Deserializer value
   */
  public void setDeserializer(MessageDeserializer md) {
    endpoint.setDeserializer(md);
  }

  /**
   * This method makes an attempt to route the message to the root of the given
   * id. The hint handle will be the first hop in the route. If the id field is
   * null, then the message is routed directly to the given node, and delivers
   * the message there. If the hint field is null, then this method makes an
   * attempt to route the message to the root of the given id. Note that one of
   * the id and hint fields can be null, but not both.
   *
   * @param id The destination Id of the message.
   * @param message The message to deliver
   * @param hint The first node to send this message to, optional
   */
  public void route(Id id, Message message, NodeHandle hint) {
    if (message instanceof RawMessage) {
      route(id, (RawMessage) message, hint);
    } else {
      route(id, new JavaSerializedMessage(message), hint);
    }
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param id DESCRIBE THE PARAMETER
   * @param message DESCRIBE THE PARAMETER
   * @param hint DESCRIBE THE PARAMETER
   */
  public void route(Id id, RawMessage message, NodeHandle hint) {
    RingId mId = (RingId) id;
    MultiringNodeHandle mHint = (MultiringNodeHandle) hint;

    if (mId == null) {
      if (mHint.getRingId().equals(node.getRingId())) {
        endpoint.route(null, message, mHint.getHandle());
      } else {
        route(mHint.getId(), message, null);
      }
    } else {
      if (mId.getRingId().equals(node.getRingId())) {
        if ((mHint != null) && (mHint.getRingId().equals(node.getRingId()))) {
          endpoint.route(mId.getId(), message, mHint.getHandle());
        } else {
          endpoint.route(mId.getId(), message, null);
        }
      } else {
        node.getCollection().route(mId, message, getInstance());
      }
    }
  }


  /**
   * This call produces a list of nodes that can be used as next hops on a route
   * towards the given id, such that the resulting route satisfies the overlay
   * protocol's bounds on the number of hops taken. If the safe flag is
   * specified, then the fraction of faulty nodes returned is no higher than the
   * fraction of faulty nodes in the overlay.
   *
   * @param id The destination id.
   * @param num The number of nodes to return.
   * @param safe Whether or not to return safe nodes.
   * @return DESCRIBE THE RETURN VALUE
   */
  public NodeHandleSet localLookup(Id id, int num, boolean safe) {
    return new MultiringNodeHandleSet(node.getRingId(), endpoint.localLookup(((RingId) id).getId(), num, safe));
  }

  /**
   * This methods returns an unordered set of nodehandles on which are neighbors
   * of the local node in the id space. Up to num handles are returned.
   *
   * @param num The number of desired handle to return.
   * @return DESCRIBE THE RETURN VALUE
   */
  public NodeHandleSet neighborSet(int num) {
    return new MultiringNodeHandleSet(node.getRingId(), endpoint.neighborSet(num));
  }

  /**
   * This methods returns an ordered set of nodehandles on which replicas of an
   * object with a given id can be stored. The call returns nodes up to and
   * including a node with maxRank.
   *
   * @param id The object's id.
   * @param maxRank The number of desired replicas.
   * @return DESCRIBE THE RETURN VALUE
   */
  public NodeHandleSet replicaSet(Id id, int maxRank) {
    if (((RingId) id).getRingId().equals(node.getRingId())) {
      return new MultiringNodeHandleSet(node.getRingId(), endpoint.replicaSet(((RingId) id).getId(), maxRank));
    } else {
      return new MultiringNodeHandleSet(((RingId) id).getRingId(), node.getNode().getIdFactory().buildNodeHandleSet());
    }
  }

  /**
   * This methods returns an ordered set of nodehandles on which replicas of an