com.orientechnologies.orient.graph.sql.functions

Class OSQLFunctionDijkstra

java.lang.Object

com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract

com.orientechnologies.orient.core.sql.functions.math.OSQLFunctionMathAbstract

com.orientechnologies.orient.graph.sql.functions.OSQLFunctionPathFinder

com.orientechnologies.orient.graph.sql.functions.OSQLFunctionDijkstra

All Implemented Interfaces:

OSQLFunction

public class OSQLFunctionDijkstra
extends OSQLFunctionPathFinder

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--orientechnologies.com)

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME

Fields inherited from class com.orientechnologies.orient.graph.sql.functions.OSQLFunctionPathFinder

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

Fields inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract

configuredParameters

Fields inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

maxParams, minParams, name

Constructor Summary

Constructors

Constructor and Description
OSQLFunctionDijkstra()

Method Summary

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

Methods inherited from class com.orientechnologies.orient.graph.sql.functions.OSQLFunctionPathFinder

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

Methods inherited from class com.orientechnologies.orient.core.sql.functions.math.OSQLFunctionMathAbstract

getClassWithMorePrecision, getContextValue, shouldMergeDistributedResult

Methods inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract

config, toString

Methods inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

filterResult, getDistributedStorageId, getMaxParams, getMinParams, getName, mergeDistributedResult, returnDistributedResult, setResult

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

OSQLFunctionDijkstra

public OSQLFunctionDijkstra()

Method Detail

execute

public LinkedList<OrientVertex> execute(Object iThis,
                                        OIdentifiable iCurrentRecord,
                                        Object iCurrentResult,
                                        Object[] iParams,
                                        OCommandContext iContext)

Description copied from interface: OSQLFunction

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: OSQLFunction

Returns a convinient 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(OrientVertex node,
                            OrientVertex target)

Specified by:

getDistance in class OSQLFunctionPathFinder

isVariableEdgeWeight

protected boolean isVariableEdgeWeight()

Overrides:

isVariableEdgeWeight in class OSQLFunctionPathFinder