rice.pastry.client
Class CommonAPIAppl

java.lang.Object
  rice.pastry.client.PastryAppl
      rice.pastry.client.CommonAPIAppl

Direct Known Subclasses:

RegrTestApp

public abstract class CommonAPIAppl
extends PastryAppl

CommonAPIAppl is an abstract class that all new applications should extend. It provides the common KBR API defined in "Towards a Common API for Structured Peer-to-Peer Overlays." Frank Dabek, Ben Zhao, Peter Druschel, John Kubiatowicz and Ion Stoica. In Proceedings of the 2nd International Workshop on Peer-to-peer Systems (IPTPS'03) , Berkeley, CA, February 2003.

Version:

$Id: CommonAPIAppl.java 3524 2007-01-09 14:09:27Z jeffh $

Author:

Peter Druschel

Field Summary

Fields inherited from class rice.pastry.client.PastryAppl

address, deserializer, instance, logger, receiver, thePastryNode

Constructor Summary

CommonAPIAppl(PastryNode pn)
Constructor.

CommonAPIAppl(PastryNode pn, java.lang.String instance)
Constructor.

Method Summary

abstract void	deliver(Id key, Message msg) Called by pastry when a message arrives for this application.
void	forward(RouteMessage msg) Called by pastry when a message is enroute and is passing through this node.
void	leafSetChange(NodeHandle nh, boolean wasAdded) Called by pastry when the leaf set changes.
NodeSet	localLookup(Id key, int num, boolean safe) This method produces a list of nodes that can be used as next hops on a route towards key, such that the resulting route satisfies the overlay protocol's bounds on the number of hops taken.
void	messageForAppl(Message msg) Called by pastry when a message arrives for this application.
NodeSet	neighborSet(int num) This method produces an unordered list of nodehandles that are neighbors of the local node in the ID space.
void	notifyReady() Invoked when the Pastry node has joined the overlay network and is ready to send and receive messages
IdRange	range(NodeHandle n, int r, Id key) This method provides information about ranges of keys for which the node n is currently a r-root.
IdRange	range(NodeHandle n, int r, Id key, boolean cumulative) This method provides information about ranges of keys for which the node n is currently a r-root.
void	receiveMessage(Message msg) Called by pastry to deliver a message to this client.
NodeSet	replicaSet(Id key, int max_rank) This method returns an ordered set of nodehandles on which replicas of the object with key can be stored.
void	route(Id key, Message msg, NodeHandle hint) This operation forwards a message towards the root of key.
void	update(NodeHandle nh, boolean joined) Called by pastry when the neighbor set changes.

Methods inherited from class rice.pastry.client.PastryAppl

accept, connect, deliverWhenNotReady, destroy, enrouteMessage, getAddress, getLeafSet, getNodeHandle, getNodeId, getRoutingTable, isClosest, receiveMessageInternal, receiveSocket, register, routeMsg, routeMsgDirect, routeSetChange, setDeserializer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CommonAPIAppl

public CommonAPIAppl(PastryNode pn)

Constructor.

Parameters:

pn - the pastry node that the application attaches to.

CommonAPIAppl

public CommonAPIAppl(PastryNode pn,
                     java.lang.String instance)

Constructor.

Parameters:

pn - the pastry node that the application attaches to.

Method Detail

route

public void route(Id key,
                  Message msg,
                  NodeHandle hint)

This operation forwards a message towards the root of key. The optional hint argument specifies a node that should be used as a first hop in routing the message. A good hint, e.g. one that refers to the key's current root, can result in the message being delivered in one hop; a bad hint adds at most one extra hop to the route. Either K or hint may be NULL, but not both. The operation provides a best-effort service: the message may be lost, duplicated, corrupted, or delayed indefinitely.

Parameters:

key - the key

msg - the message to deliver.

hint - the hint

localLookup

public NodeSet localLookup(Id key,
                           int num,
                           boolean safe)

This method produces a list of nodes that can be used as next hops on a route towards key, such that the resulting route satisfies the overlay protocol's bounds on the number of hops taken. If safe is true, the expected fraction of faulty nodes in the list is guaranteed to be no higher than the fraction of faulty nodes in the overlay; if false, the set may be chosen to optimize performance at the expense of a potentially higher fraction of faulty nodes. This option allows applications to implement routing in overlays with byzantine node failures. Implementations that assume fail-stop behavior may ignore the safe argument. The fraction of faulty nodes in the returned list may be higher if the safe parameter is not true because, for instance, malicious nodes have caused the local node to build a routing table that is biased towards malicious nodes~\cite{Castro02osdi}.

Parameters:

key - the message's key

num - the maximal number of next hops nodes requested

safe -

Returns:

the nodehandle set

neighborSet

public NodeSet neighborSet(int num)

This method produces an unordered list of nodehandles that are neighbors of the local node in the ID space. Up to num node handles are returned.

Parameters:

num - the maximal number of nodehandles requested

Returns:

the nodehandle set

replicaSet

public NodeSet replicaSet(Id key,
                          int max_rank)

This method returns an ordered set of nodehandles on which replicas of the object with key can be stored. The call returns nodes with a rank up to and including max_rank. If max_rank exceeds the implementation's maximum replica set size, then its maximum replica set is returned. The returned nodes may be used for replicating data since they are precisely the nodes which become roots for the key when the local node fails.

Parameters:

key - the key

max_rank - the maximal number of nodehandles returned

Returns:

the replica set

range

public IdRange range(NodeHandle n,
                     int r,
                     Id key,
                     boolean cumulative)

This method provides information about ranges of keys for which the node n is currently a r-root. The operations returns null if the range could not be determined. It is an error to query the range of a node not present in the neighbor set as returned by the update upcall or the neighborSet call. Some implementations may have multiple, disjoint ranges of keys for which a given node is responsible (Pastry has two). The parameter key allows the caller to specify which range should be returned. If the node referenced by n is the r-root for key, then the resulting range includes key. Otherwise, the result is the nearest range clockwise from key for which n is responsible.

Parameters:

n - nodeHandle of the node whose range is being queried

r - the rank

key - the key

cumulative - if true, returns ranges for which n is an i-root for 0 Returns:

the range of keys, or null if range could not be determined for the given node and rank

range

public IdRange range(NodeHandle n,
                     int r,
                     Id key)

This method provides information about ranges of keys for which the node n is currently a r-root. The operations returns null if the range could not be determined. It is an error to query the range of a node not present in the neighbor set as returned by the update upcall or the neighborSet call. Some implementations may have multiple, disjoint ranges of keys for which a given node is responsible (Pastry has two). The parameter key allows the caller to specify which range should be returned. If the node referenced by n is the r-root for key, then the resulting range includes key. Otherwise, the result is the nearest range clockwise from key for which n is responsible.

Parameters:

n - nodeHandle of the node whose range is being queried

r - the rank

key - the key

Returns:

the range of keys, or null if range could not be determined for the given node and rank

deliver

public abstract void deliver(Id key,
                             Message msg)

Called by pastry when a message arrives for this application.

Parameters:

msg - the message that is arriving.

forward

public void forward(RouteMessage msg)

Called by pastry when a message is enroute and is passing through this node. If this method is not overridden, the default behaviour is to let the message pass through.

Parameters:

msg - the message that is passing through.

key - the key

nextHop - the default next hop for the message.

update

public void update(NodeHandle nh,
                   boolean joined)

Called by pastry when the neighbor set changes.

Parameters:

nh - the handle of the node that was added or removed.

wasAdded - true if the node was added, false if the node was removed.

notifyReady

public void notifyReady()

Invoked when the Pastry node has joined the overlay network and is ready to send and receive messages

Overrides:

notifyReady in class PastryAppl

messageForAppl

public final void messageForAppl(Message msg)

Description copied from class: PastryAppl

Called by pastry when a message arrives for this application.

Specified by:

messageForAppl in class PastryAppl

Parameters:

msg - the message that is arriving.

leafSetChange

public final void leafSetChange(NodeHandle nh,
                                boolean wasAdded)

Called by pastry when the leaf set changes.

Overrides:

leafSetChange in class PastryAppl

Parameters:

nh - the handle of the node that was added or removed.

wasAdded - true if the node was added, false if the node was removed.

receiveMessage

public void receiveMessage(Message msg)

Called by pastry to deliver a message to this client. Not to be overridden.

Overrides:

receiveMessage in class PastryAppl

Parameters:

msg - the message that is arriving.