meteor.dht.chord
Interface ChordService

All Superinterfaces:

DHTService, net.jxta.platform.Module, net.jxta.service.Service

All Known Implementing Classes:

ChordServiceImpl

public interface ChordService

extends DHTService

The interface defining the Chord Service

Author:

Vincent Matossian December 2003

Field Summary

static java.lang.String

refModuleClassID The module class identifier of this service that may be used as a handler name when filtering messages

Fields inherited from interface net.jxta.platform.Module

START_AGAIN_PROGRESS, START_AGAIN_STALLED, START_OK

Method Summary

void	addListener(DHTListener c) Add a listener
void	blockOnSend() Synchronization for the Messaging between peers
void	checkPredecessor() Checks if predecessor is alive If not remove the current predecessor
java.math.BigInteger	closest_preceding_node(java.math.BigInteger target) If the id of the successor of the node we are at is between this identifier and the desired identifier, return this node
java.math.BigInteger	find_predecessor(java.math.BigInteger id, int mode, int owner) Finds the predecessor of an id Blocking call
void	find_successor(QueryMessage q) Is called by lookup, it in turn calls find_predecessor and returns the successor of this (found) predecessor
void	fix_fingers() Periodically fix fingers by finding successor of the next identifier (n+1,2,4,8,16 etc...)
FingerTable	getFingerTable()
boolean	inInterval(java.math.BigInteger id, java.math.BigInteger begin, java.math.BigInteger end, boolean incLeft, boolean incRight) Checks whether id is in the interval [begin,end] or (begin,end) depending on the boolean inclusive
void	init_finger_table(java.math.BigInteger bootstrap) Init the finger table
boolean	isLocal(java.math.BigInteger id)
int	log2(java.math.BigInteger x) Log base 2
void	lookup(java.math.BigInteger id, int owner) Lookup the successor of an identifier
void	lookup(java.math.BigInteger id, int owner, java.lang.String squidQuery) Lookup the successor of an identifier with a Squid Query
void	notify(java.math.BigInteger yourPred) Notify a successor that id might be its predecessor
void	notifyReceived() Invoked in messageHandler's processResponse to notify the lookup Service that a response for its blocking query has just been received, and the response identifier of the query set as successor ID.
void	receivedPredecessor(java.math.BigInteger predecessor) When a predecessor query is answered this method is invoked from the MessageHandler processResponse.
void	receivedSuccessor(QueryMessage qm) This method is invoked from the MessageHandler processResponse.
void	removeListener(DHTListener c) Remove a listener
void	stabilize() Stabilization protocol
void	update_finger_table(QueryMessage q) UPdate finger table
void	update_others() Update others to point to newly joined node

Methods inherited from interface meteor.dht.DHTService

bootstrap, get, getNodeID, getTopologySize, join, lookup, put, setTopologySize

Methods inherited from interface net.jxta.service.Service

getImplAdvertisement, getInterface

Methods inherited from interface net.jxta.platform.Module

init, startApp, stopApp

Field Detail

refModuleClassID

public static final java.lang.String refModuleClassID

The module class identifier of this service that may be used as a handler name when filtering messages

See Also:

Constant Field Values

Method Detail

addListener

public void addListener(DHTListener c)

Add a listener

removeListener

public void removeListener(DHTListener c)

Remove a listener

getFingerTable

public FingerTable getFingerTable()

Returns:

returns the finger table

log2

public int log2(java.math.BigInteger x)

Log base 2

init_finger_table

public void init_finger_table(java.math.BigInteger bootstrap)

Init the finger table

update_others

public void update_others()

Update others to point to newly joined node

update_finger_table

public void update_finger_table(QueryMessage q)

UPdate finger table

find_successor

public void find_successor(QueryMessage q)

Is called by lookup, it in turn calls find_predecessor and returns the successor of this (found) predecessor

find_predecessor

public java.math.BigInteger find_predecessor(java.math.BigInteger id,
                                             int mode,
                                             int owner)

Finds the predecessor of an id Blocking call

closest_preceding_node

public java.math.BigInteger closest_preceding_node(java.math.BigInteger target)

If the id of the successor of the node we are at is between this identifier and the desired identifier, return this node

inInterval

public boolean inInterval(java.math.BigInteger id,
                          java.math.BigInteger begin,
                          java.math.BigInteger end,
                          boolean incLeft,
                          boolean incRight)

Checks whether id is in the interval [begin,end] or (begin,end) depending on the boolean inclusive

isLocal

public boolean isLocal(java.math.BigInteger id)

Returns:

true if the identifier is in range

stabilize

public void stabilize()

Stabilization protocol

notify

public void notify(java.math.BigInteger yourPred)

Notify a successor that id might be its predecessor

receivedPredecessor

public void receivedPredecessor(java.math.BigInteger predecessor)

When a predecessor query is answered this method is invoked from the MessageHandler processResponse. This is part of the stabilization protocol, when a successor node returns its predecessor. The predecessor ID is checked for existence in (localID,successor) If it does belong between this node's id and its successor then this node's successor is updated and a Notification message is sent to our successor to inform it that we are its "new" predecessor.

Parameters:

predecessor - the returned predecessor ID from this node's successor

receivedSuccessor

public void receivedSuccessor(QueryMessage qm)

This method is invoked from the MessageHandler processResponse. Similarly to receivedPredecessor, receivedSuccessor is raised when a node returns a successor identifier. This is used more often than for Predecessor queries, as it is needed by the JOIN Protocol, FINGER FIXING protocol as well as any Identifier LOOKUP.

blockOnSend

public void blockOnSend()

Synchronization for the Messaging between peers

notifyReceived

public void notifyReceived()

Invoked in messageHandler's processResponse to notify the lookup Service that a response for its blocking query has just been received, and the response identifier of the query set as successor ID.

fix_fingers

public void fix_fingers()

Periodically fix fingers by finding successor of the next identifier (n+1,2,4,8,16 etc...)

checkPredecessor

public void checkPredecessor()

Checks if predecessor is alive If not remove the current predecessor

lookup

public void lookup(java.math.BigInteger id,
                   int owner)

Lookup the successor of an identifier

lookup

public void lookup(java.math.BigInteger id,
                   int owner,
                   java.lang.String squidQuery)

Lookup the successor of an identifier with a Squid Query