Package com.arcadedb.query.sql.function.graph

Class SQLFunctionDijkstra

java.lang.Object

com.arcadedb.query.sql.function.SQLFunctionAbstract

com.arcadedb.query.sql.function.SQLFunctionConfigurableAbstract

com.arcadedb.query.sql.function.math.SQLFunctionMathAbstract

com.arcadedb.query.sql.function.graph.SQLFunctionPathFinder

com.arcadedb.query.sql.function.graph.SQLFunctionDijkstra

All Implemented Interfaces:

SQLFunction

public class SQLFunctionDijkstra
extends SQLFunctionPathFinder

Dijkstra's algorithm describes how to find the cheapest path from one node to another node in a directed weighted graph.

The first parameter is source record. The second parameter is destination record. The third parameter is a name of property that represents 'weight'.

If property is not defined in edge or is null, distance between vertexes are 0.

Author:

Luca Garulli (l.garulli--(at)--gmail.com)

Field Summary

Fields

Modifier and Type	Field	Description
static String	NAME

Fields inherited from class com.arcadedb.query.sql.function.graph.SQLFunctionPathFinder

context, distance, MIN, paramDestinationVertex, paramDirection, paramSourceVertex, predecessors, unSettledNodes

Fields inherited from class com.arcadedb.query.sql.function.SQLFunctionConfigurableAbstract

configuredParameters

Fields inherited from class com.arcadedb.query.sql.function.SQLFunctionAbstract

name

Constructor Summary

Constructors

Constructor	Description
SQLFunctionDijkstra()

Method Summary

Modifier and Type	Method	Description
LinkedList<Vertex>	execute(Object iThis, Identifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, CommandContext iContext)	Process a record.
protected float	getDistance(Vertex node, Vertex target)
String	getSyntax()	Returns a convenient SQL String representation of the function.
protected boolean	isVariableEdgeWeight()

Methods inherited from class com.arcadedb.query.sql.function.graph.SQLFunctionPathFinder

aggregateResults, continueTraversing, execute, findMinimalDistances, getMinimum, getNeighbors, getPath, getResult, getShortestDistance, isNotSettled, sumDistances

Methods inherited from class com.arcadedb.query.sql.function.math.SQLFunctionMathAbstract

getClassWithMorePrecision, getContextValue

Methods inherited from class com.arcadedb.query.sql.function.SQLFunctionConfigurableAbstract

config, toString

Methods inherited from class com.arcadedb.query.sql.function.SQLFunctionAbstract

getName

Methods inherited from class java.lang.Object

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

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

Constructor Detail

SQLFunctionDijkstra

public SQLFunctionDijkstra()

Method Detail

execute

public LinkedList<Vertex> execute(Object iThis,
                                  Identifiable iCurrentRecord,
                                  Object iCurrentResult,
                                  Object[] iParams,
                                  CommandContext iContext)

Description copied from interface: SQLFunction

Process a record.

iCurrentRecord - : current record

iCurrentResult - TODO

iParams - : function parameters, number is ensured to be within minParams and maxParams.

iContext - : object calling this function

Returns:

function result, can be null. Special cases : can be null if function aggregate results, can be null if function filter results : this mean result is excluded

getSyntax

public String getSyntax()

Description copied from interface: SQLFunction

Returns a convenient SQL String representation of the function.

Example :

  myFunction( param1, param2, [optionalParam3])
 

This text will be used in exception messages.

Returns:

String , never null.

getDistance

protected float getDistance(Vertex node,
                            Vertex target)

Specified by:

getDistance in class SQLFunctionPathFinder

isVariableEdgeWeight

protected boolean isVariableEdgeWeight()

Overrides:

isVariableEdgeWeight in class SQLFunctionPathFinder