viceroy
Class TraverseTreePlusAlgorithm

java.lang.Object
  |
  +--viceroy.PapersAlgorithm
        |
        +--viceroy.TraverseTreePlusAlgorithm

All Implemented Interfaces:

LookupAlgorithm

public class TraverseTreePlusAlgorithm

extends PapersAlgorithm

implements LookupAlgorithm

Change the TraverseTree phase in the lookup algorithm The change is as follows: if one of the children exists - certainly go to one of them. else goto TraveseRingPhase

Since:

1.72

Author:

Anat Talmy

, Oren Dobzinski

Field Summary

private static org.apache.log4j.Logger

logger logger for debug

Fields inherited from class viceroy.PapersAlgorithm

messagePath, state

Constructor Summary

TraverseTreePlusAlgorithm(AuthorizedViceroyPeer peer)
a constructor

Method Summary

protected ViceroyPeer	lookupTraverseTree(AuthorizedViceroyPeer peer, Resource valueToLook) Performs the traverse tree phase in the lookup algorithm.
LookupAlgorithm	newLookupAlgorithm(AuthorizedViceroyPeer peer) creates a fresh new lookup algorithm, with empty path

Methods inherited from class viceroy.PapersAlgorithm

getLookupState, getMessagePath, goToLeftChild, goToParent, goToPredecessor, goToRightChild, goToSuccessor, howOvershoots, lookupProceedToRoot, lookupTraverseRing, nextOnLookup, overshoots

Methods inherited from class java.lang.Object

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

Methods inherited from interface viceroy.LookupAlgorithm

getMessagePath, nextOnLookup

Field Detail

logger

private static final org.apache.log4j.Logger logger

logger for debug

Constructor Detail

TraverseTreePlusAlgorithm

public TraverseTreePlusAlgorithm(AuthorizedViceroyPeer peer)

a constructor

Parameters:

peer -

Method Detail

lookupTraverseTree

protected ViceroyPeer lookupTraverseTree(AuthorizedViceroyPeer peer,
                                         Resource valueToLook)
                                  throws ResourceNotFoundException

Performs the traverse tree phase in the lookup algorithm. This phase is as follows: if one of the children exists - certainly go to one of them.

 if( clockwiseDist(this,val) < 1/2^level &&
     leftChild &&
     !overshoot(leftChild,val) )
   goto leftChild
 
 else if ( clockwiseDist(this,val) >=1/2^level &&
           rightChild &&
           !overshoot(rightChild,val) )
        goto rightChild
 
 else if ( leftChild && rightChild==null )
        goto leftChild
        
 else if ( rightChild && leftChild==null )
        goto rightChild
        
 else if ( leftChild && rightChild)
         goto the child that least overshoots
               
 else goto traverse ring phase
 

Overrides:

lookupTraverseTree in class PapersAlgorithm

Parameters:

peer - the current peer

valueToLook -

Returns:

the next peer to go to according the lookup algorithm

Throws:

ResourceNotFoundException

newLookupAlgorithm

public LookupAlgorithm newLookupAlgorithm(AuthorizedViceroyPeer peer)

creates a fresh new lookup algorithm, with empty path

Specified by:

newLookupAlgorithm in interface LookupAlgorithm

Overrides:

newLookupAlgorithm in class PapersAlgorithm

Parameters:

peer - starting point of the new algorithm

Returns:

a fresh new lookup algorithm, with empty path