eu.stratosphere.example.java.record.shortestpaths

Class PairwiseSP

java.lang.Object

eu.stratosphere.example.java.record.shortestpaths.PairwiseSP

All Implemented Interfaces:

Program, ProgramDescription

public class PairwiseSP
extends Object
implements Program, ProgramDescription

Implementation of the Pairwise Shortest Path example PACT program. The program implements one iteration of the algorithm and must be run multiple times until no changes are computed. The pairwise shortest path algorithm comes from the domain graph problems. The goal is to find all shortest paths between any two transitively connected nodes in a graph. In this implementation edges are interpreted as directed and weighted. For the first iteration, the program allows two input formats: 1) RDF triples with foaf:knows predicates. A triple is interpreted as an edge from the RDF subject to the RDF object with weight 1. 2) The programs text-serialization for paths (see @see PathInFormat and @see PathOutFormat). The RDF input format is used if the 4th parameter of the getPlan() method is set to "true". If set to "false" the path input format is used.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PairwiseSP.ConcatPaths Concatenates two paths where the from-node of the first path and the to-node of the second path are the same.
static class	PairwiseSP.FindShortestPath Gets two lists of paths as input and emits for each included from-node/to-node combination the shortest path(s).
static class	PairwiseSP.PathInFormat The PathInFormat reads paths consisting of a from-node a to-node, a length, and hop node list serialized as a string.
static class	PairwiseSP.PathOutFormat The PathOutFormat serializes paths to text.
static class	PairwiseSP.RDFTripleInFormat Reads RDF triples and filters on the foaf:knows RDF predicate.

Constructor Summary

Constructors

Constructor and Description
PairwiseSP()

Method Summary

Methods

Modifier and Type	Method and Description
String	getDescription()
Plan	getPlan(String... args) Assembles the Plan of the Pairwise Shortest Paths example Pact program.

Methods inherited from class java.lang.Object

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

Constructor Detail

PairwiseSP

public PairwiseSP()

Method Detail

getPlan

public Plan getPlan(String... args)

Assembles the Plan of the Pairwise Shortest Paths example Pact program. The program computes one iteration of the Pairwise Shortest Paths algorithm. For the first iteration, two input formats can be chosen: 1) RDF triples with foaf:knows predicates 2) Text-serialized paths (see PathInFormat and PathOutFormat) To choose 1) set the forth parameter to "true". If set to "false" 2) will be used.

Specified by:

getPlan in interface Program

getDescription

public String getDescription()

Specified by:

getDescription in interface ProgramDescription