gcendpoint.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.gc;

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.*;

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

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

  /**
   * Constructor
   *
   * @param endpoint DESCRIBE THE PARAMETER
   */
  protected GCEndpoint(Endpoint endpoint) {
    this.endpoint = endpoint;
  }

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

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

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

  /**
   * Sets the Deserializer attribute of the GCEndpoint 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) {
    endpoint.route(id, 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) {
    endpoint.route(id, message, hint);
  }

  /**
   * 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 endpoint.localLookup(id, 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 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) {
    return endpoint.replicaSet(id, maxRank);
  }

  /**
   * 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. This call also allows the application to
   * provide a remove "center" node, as well as other nodes in the vicinity.
   *
   * @param id The object's id.
   * @param maxRank The number of desired replicas.
   * @param set The set of other nodes around the root handle
   * @param root DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public NodeHandleSet replicaSet(Id id, int maxRank, NodeHandle root, NodeHandleSet set) {
    return endpoint.replicaSet(id, maxRank, root, set);
  }

  /**
   * This operation provides information about ranges of keys for which the node
   * is currently a rank-root. The operations returns null if the range could
   * not be determined, the range otherwise. It is an error to query the range
   * of a node not present in the neighbor set as returned bythe update upcall
   * or the neighborSet call. Certain implementations may return an error if
   * rank is greater than zero. Some protocols may have multiple, disjoint
   * ranges of keys for which a given node is responsible. The parameter lkey
   * allows the caller to specify which region should be returned. If the node
   * referenced by is responsible for key lkey, then the resulting range
   * includes lkey. Otherwise, the result is the nearest range clockwise from
   * lkey for which is responsible.
   *
   * @param handle The handle whose range to check.
   * @param rank The root rank.
   * @param lkey An "index" in case of multiple ranges.
   * @return DESCRIBE THE RETURN VALUE
   */
  public IdRange range(NodeHandle handle, int rank, Id lkey) {
    IdRange range = endpoint.range(handle, rank, lkey);
    return (range == null ? null : new GCIdRange(range));
  }

  /**
   * This operation provides information about ranges of keys for which the node
   * is currently a rank-root. The operations returns null if the range could
   * not be determined, the range otherwise. It is an error to query the range
   * of a node not present in the neighbor set as returned bythe update upcall
   * or the neighborSet call. Certain implementations may return an error if
   * rank is greater than zero. Some protocols may have multiple, disjoint
   * ranges of keys for which a given node is responsible. The parameter lkey
   * allows the caller to specify which region should be returned. If the node
   * referenced by is responsible for key lkey, then the resulting range
   * includes lkey. Otherwise, the result is the nearest range clockwise from
   * lkey for which is responsible.
   *
   * @param handle The handle whose range to check.
   * @param rank The root rank.
   * @param lkey An "index" in case of multiple ranges.
   * @param cumulative Whether to return the cumulative or single range
   * @return DESCRIBE THE RETURN VALUE
   */
  public IdRange range(NodeHandle handle, int rank, Id lkey, boolean cumulative) {
    IdRange range = endpoint.range(handle, rank, lkey, cumulative);
    return (range == null ? null : new GCIdRange(range));
  }

  /**
   * Schedules a message to be delivered to this application after the provided
   * number of milliseconds.
   *
   * @param message The message to be delivered
   * @param delay The number of milliseconds to wait before delivering the
   *      message
   * @return DESCRIBE THE RETURN VALUE
   */
  public CancellableTask scheduleMessage(Message message, long delay) {
    return endpoint.scheduleMessage(message, delay);
  }

  /**
   * Schedules a message to be delivered to this application every period number
   * of milliseconds, after delay number of miliseconds have passed.
   *
   * @param message The message to be delivered
   * @param delay The number of milliseconds to wait before delivering the fist
   *      message
   * @param period DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public CancellableTask scheduleMessage(Message message, long delay, long period) {
    return endpoint.scheduleMessage(message, delay, period);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param message DESCRIBE THE PARAMETER
   * @param delay DESCRIBE THE PARAMETER
   * @param period DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public CancellableTask scheduleMessageAtFixedRate(Message message, long delay, long period) {
    return endpoint.scheduleMessageAtFixedRate(message, delay, period);
  }

  /**
   * Schedules a job for processing on the dedicated processing thread. CPU
   * intensive jobs, such as encryption, erasure encoding, or bloom filter
   * creation should never be done in the context of the underlying node's
   * thread, and should only be done via this method.
   *
   * @param task The task to run on the processing thread
   * @param command The command to return the result to once it's done
   */
  public void process(Executable task, Continuation command) {
    endpoint.process(task, command);
  }

  /**
   * Passthrough to the sub endpoint.
   *
   * @param handle DESCRIBE THE PARAMETER
   * @param receiver DESCRIBE THE PARAMETER
   * @param timeout DESCRIBE THE PARAMETER
   */
  public void connect(NodeHandle handle, AppSocketReceiver receiver, int timeout) {
    endpoint.connect(handle, receiver, timeout);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param receiver DESCRIBE THE PARAMETER
   */
  public void accept(AppSocketReceiver receiver) {
    endpoint.accept(receiver);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @param type DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public Id readId(InputBuffer buf, short type) throws IOException {
    if (type == GCId.TYPE) {
      return new GCId(buf, endpoint);
    }

    return endpoint.readId(buf, type);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public NodeHandle readNodeHandle(InputBuffer buf) throws IOException {
    return endpoint.readNodeHandle(buf);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public IdRange readIdRange(InputBuffer buf) throws IOException {
    return new GCIdRange(buf, endpoint);
    //.readIdRange(buf);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param handle DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public NodeHandle coalesce(NodeHandle handle) {
    return endpoint.coalesce(handle);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @param type DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public NodeHandleSet readNodeHandleSet(InputBuffer buf, short type) throws IOException {
    return endpoint.readNodeHandleSet(buf, type);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  public String toString() {
    return "GCE[" + endpoint + "]";
  }

  /**
   * DESCRIBE THE METHOD
   */
  public void register() {
    endpoint.register();
  }
}