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

Class SQLFunctionAstar

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.SQLFunctionHeuristicPathFinderAbstract

com.arcadedb.query.sql.function.graph.SQLFunctionAstar

All Implemented Interfaces:

SQLFunction

public class SQLFunctionAstar
extends SQLFunctionHeuristicPathFinderAbstract

A*'s algorithm describes how to find the cheapest path from one node to another node in a directed weighted graph with husrestic function.

The first parameter is source record. The second parameter is destination record. The third parameter is a name of property that represents 'weight' and fourth parameter represents the map of options.

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

Author:

Saeed Tabrizi (saeed a_t nowcando.com)

Field Summary

Fields

Modifier and Type	Field	Description
protected Map<Vertex,Vertex>	cameFrom
protected Set<Vertex>	closedSet
protected Map<Vertex,Double>	fScore
protected Map<Vertex,Double>	gScore
static String	NAME
protected PriorityQueue<Vertex>	open

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

context, MIN, PARAM_CUSTOM_HEURISTIC_FORMULA, PARAM_D_FACTOR, PARAM_DIRECTION, PARAM_EDGE_TYPE_NAMES, PARAM_EMPTY_IF_MAX_DEPTH, PARAM_HEURISTIC_FORMULA, PARAM_MAX_DEPTH, PARAM_PARALLEL, PARAM_TIE_BREAKER, PARAM_VERTEX_AXIS_NAMES, paramCustomHeuristicFormula, paramDestinationVertex, paramDFactor, paramDirection, paramEdgeTypeNames, paramEmptyIfMaxDepth, paramHeuristicFormula, paramMaxDepth, paramParallel, paramSourceVertex, paramTieBreaker, paramVertexAxisNames, rnd, route

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
SQLFunctionAstar()

Method Summary

Modifier and Type	Method	Description
boolean	aggregateResults()	A function can make calculation on several records before returning a result.
LinkedList<Vertex>	execute(Object iThis, Identifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, CommandContext iContext)	Process a record.
protected double	getDistance(Edge edge)
protected double	getDistance(Vertex node, Vertex parent, Vertex target)
protected double	getHeuristicCost(Vertex node, Vertex parent, Vertex target, CommandContext iContext)
protected Set<Edge>	getNeighborEdges(Vertex node)
Object	getResult()	Only called when function aggregates results after all records have been passed to the function.
String	getSyntax()	Returns a convenient SQL String representation of the function.
protected boolean	isVariableEdgeWeight()

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

booleanOrDefault, doubleOrDefault, gcdist, getDiagonalHeuristicCost, getDiagonalHeuristicCost, getEuclideanHeuristicCost, getEuclideanHeuristicCost, getEuclideanNoSQRHeuristicCost, getEuclideanNoSQRHeuristicCost, getManhattanHeuristicCost, getManhattanHeuristicCost, getMaxAxisHeuristicCost, getMaxAxisHeuristicCost, getNeighbors, getPath, getSimpleHeuristicCost, getTieBreakingHeuristicCost, getTieBreakingHeuristicCost, getTieBreakingRandomHeuristicCost, integerOrDefault, longOrDefault, stringArray, stringOrDefault

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

closedSet

protected final Set<Vertex> closedSet

cameFrom

protected final Map<Vertex,Vertex> cameFrom

gScore

protected final Map<Vertex,Double> gScore

fScore

protected final Map<Vertex,Double> fScore

open

protected final PriorityQueue<Vertex> open

Constructor Detail

SQLFunctionAstar

public SQLFunctionAstar()

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

getNeighborEdges

protected Set<Edge> getNeighborEdges(Vertex node)

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.

getResult

public Object getResult()

Description copied from interface: SQLFunction

Only called when function aggregates results after all records have been passed to the function.

Specified by:

getResult in interface SQLFunction

Overrides:

getResult in class SQLFunctionAbstract

Returns:

Aggregation result

getDistance

protected double getDistance(Vertex node,
                             Vertex parent,
                             Vertex target)

Specified by:

getDistance in class SQLFunctionHeuristicPathFinderAbstract

getDistance

protected double getDistance(Edge edge)

aggregateResults

public boolean aggregateResults()

Description copied from interface: SQLFunction

A function can make calculation on several records before returning a result.

Example of such function : sum, count, max, min ...

The final result of the aggregation is obtained by calling SQLFunction.getResult()

Specified by:

aggregateResults in interface SQLFunction

Overrides:

aggregateResults in class SQLFunctionMathAbstract

Returns:

true if function aggregate results

getHeuristicCost

protected double getHeuristicCost(Vertex node,
                                  Vertex parent,
                                  Vertex target,
                                  CommandContext iContext)

Specified by:

getHeuristicCost in class SQLFunctionHeuristicPathFinderAbstract

isVariableEdgeWeight

protected boolean isVariableEdgeWeight()

Overrides:

isVariableEdgeWeight in class SQLFunctionHeuristicPathFinderAbstract