endpoint.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
for any direct, indirect, incidental, special, exemplary, or
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.commonapi;

import java.io.IOException;

import rice.*;
import rice.environment.Environment;
import rice.p2p.commonapi.appsocket.AppSocketReceiver;
import rice.p2p.commonapi.rawserialization.*;

/**
 * @(#) Endpoint.java Interface which represents a node in a peer-to-peer
 * system, regardless of the underlying protocol. This represents the *local*
 * node, upon which applications can call methods.
 *
 * @version $Id: Endpoint.java 3274 2006-05-15 16:17:47Z jeffh $
 * @author Alan Mislove
 * @author Peter Druschel
 */
public interface Endpoint extends NodeHandleReader {

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

  /**
   * 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
   */
  void route(Id id, Message message, NodeHandle hint);

  /**
   * Same as the other call, but uses the Raw serialization rather than java
   * serialization.
   *
   * @param id
   * @param message
   * @param hint
   */
  void route(Id id, RawMessage message, NodeHandle 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
   */
  NodeHandleSet localLookup(Id id, int num, boolean 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
   */
  NodeHandleSet neighborSet(int num);

  /**
   * This method 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 method is equivalent to calling
   * replicaSet(id, maxRank, getLocalNodeHandle(),
   * neighborSet(Integer.MAX_VALUE));
   *
   * @param id The object's id.
   * @param maxRank The number of desired replicas.
   * @return DESCRIBE THE RETURN VALUE
   */
  NodeHandleSet replicaSet(Id id, int 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 remote "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
   */
  NodeHandleSet replicaSet(Id id, int maxRank, NodeHandle root, NodeHandleSet 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
   * @exception RangeCannotBeDeterminedException DESCRIBE THE EXCEPTION
   */
  IdRange range(NodeHandle handle, int rank, Id lkey) throws RangeCannotBeDeterminedException;

  /**
   * 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
   * @exception RangeCannotBeDeterminedException DESCRIBE THE EXCEPTION
   */
  IdRange range(NodeHandle handle, int rank, Id lkey, boolean cumulative) throws RangeCannotBeDeterminedException;

  /**
   * 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.
   */
  NodeHandle getLocalNodeHandle();

  /**
   * 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
   */
  CancellableTask scheduleMessage(Message message, long 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
   */
  CancellableTask scheduleMessage(Message message, long delay, long period);

  /**
   * 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
   */
  CancellableTask scheduleMessageAtFixedRate(Message message, long delay, long 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
   */
  void process(Executable task, Continuation command);

  /**
   * 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();

  /**
   * Returns the environment. This allows the nodes to be virtualized within the
   * JVM
   *
   * @return the environment for this node/app.
   */
  public Environment getEnvironment();

  /**
   * Set's the acceptor for this application. If no acceptor is set, then when a
   * remote node's application opens a socket here, they will get an *Exception*
   *
   * @param receiver calls receiveSocket() when a new AppSocket is opened to
   *      this application from a remote node. Note that you must call accept()
   *      again after each socket is received to properly handle socket
   *      backlogging
   */
  public void accept(AppSocketReceiver receiver);

  /**
   * Opens a connection to this application on a remote node. If no acceptor is
   * set, then receiver will get an *Exception*
   *
   * @param receiver calls receiveSocket() when a new AppSocket is opened to
   *      this application on a remote node.
   * @param handle DESCRIBE THE PARAMETER
   * @param timeout DESCRIBE THE PARAMETER
   */
  public void connect(NodeHandle handle, AppSocketReceiver receiver, int timeout);

  /**
   * To use a more efficient serialization format than Java Serialization
   *
   * @param md
   */
  public void setDeserializer(MessageDeserializer md);

  /**
   * Returns the deserializer. The default deserializer can deserialize
   * rice.p2p.util.JavaSerializedMessage
   *
   * @return
   */
  public MessageDeserializer getDeserializer();

  /**
   * To use a more efficient serialization format than Java Serialization
   *
   * @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;

  /**
   * To use Raw Serialization
   *
   * @param buf
   * @return
   * @throws IOException
   */
  public IdRange readIdRange(InputBuffer buf) throws IOException;

  /**
   * 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;

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