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

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

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- Redistributions of source code must retain the above copyright
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- Redistributions in binary form must reproduce the above copyright
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- Neither  the name  of Rice  University (RICE) nor  the names  of its
contributors may be  used to endorse or promote  products derived from
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This software is provided by RICE and the contributors on an "as is"
basis, without any representations or warranties of any kind, express
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********************************************************************************/

package rice.p2p.multiring;

import rice.*;
import java.util.*;

import rice.environment.Environment;
import rice.p2p.commonapi.*;

/**
 * @(#) MultiringEndpoint.java This class wraps an endpoint and allows for
 * applications to transparently use multiring functionality.
 *
 * @version $Id: MultiringEndpoint.java 2807 2005-11-21 11:20:52Z 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;

  /**
   * 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;
  }

  /**
   * 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();
  }

  /**
   * 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) {
    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
   * 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) {
    if (((RingId) id).getRingId().equals(node.getRingId())) {
      return new MultiringNodeHandleSet(node.getRingId(), endpoint.replicaSet(((RingId) id).getId(),
        maxRank,
        ((MultiringNodeHandle) root).getHandle(),
        ((MultiringNodeHandleSet) set).getSet()));
    } else {
      return new MultiringNodeHandleSet(((RingId) id).getRingId(), node.getNode().getIdFactory().buildNodeHandleSet());
    }
  }

  /**
   * 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) {
    if (lkey != null) {
      lkey = ((RingId) lkey).getId();
    }

    IdRange result = endpoint.range(((MultiringNodeHandle) handle).getHandle(), rank, lkey);

    if (result != null) {
      return new MultiringIdRange(node.getRingId(), result);
    } else {
      return null;
    }
  }

  /**
   * 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) {
    if (lkey != null) {
      lkey = ((RingId) lkey).getId();
    }

    IdRange result = endpoint.range(((MultiringNodeHandle) handle).getHandle(), rank, lkey, cumulative);

    if (result != null) {
      return new MultiringIdRange(node.getRingId(), result);
    } else {
      return null;
    }
  }

  /**
   * 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);
  }

  /**
   * Internal method which delivers the message to the application
   *
   * @param id The target id
   * @param target DESCRIBE THE PARAMETER
   */
  protected void deliver(RingId id, Message target) {
    application.deliver(id, target);
  }

}


