Package com.orientechnologies.orient.core.sql.functions.graph

Class OSQLFunctionAstar

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.core.sql.functions.graph.OSQLFunctionHeuristicPathFinderAbstract

com.orientechnologies.orient.core.sql.functions.graph.OSQLFunctionAstar

All Implemented Interfaces:

OSQLFunction

public class OSQLFunctionAstar
extends OSQLFunctionHeuristicPathFinderAbstract

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 represnts 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<OVertex,OVertex>	cameFrom
protected Set<OVertex>	closedSet
protected Map<OVertex,Double>	fScore
protected Map<OVertex,Double>	gScore
static final String	NAME
protected PriorityQueue<OVertex>	open

Fields inherited from class com.orientechnologies.orient.core.sql.functions.graph.OSQLFunctionHeuristicPathFinderAbstract

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.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	Description
OSQLFunctionAstar()

Method Summary

Modifier and Type	Method	Description
boolean	aggregateResults()	A function can make calculation on several records before returning a result.
LinkedList<OVertex>	execute(Object iThis, OIdentifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, OCommandContext iContext)	Process a record.
protected double	getDistance(OEdge edge)
protected double	getDistance(OVertex node, OVertex parent, OVertex target)
protected double	getHeuristicCost(OVertex node, OVertex parent, OVertex target, OCommandContext iContext)
protected Set<OEdge>	getNeighborEdges(OVertex 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.orientechnologies.orient.core.sql.functions.graph.OSQLFunctionHeuristicPathFinderAbstract

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

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, getSingleItem, getSingleProperty, mergeDistributedResult, returnDistributedResult, setResult

Methods inherited from class java.lang.Object

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

Field Details

NAME

public static final String NAME

See Also:

• Constant Field Values

closedSet

protected Set<OVertex> closedSet

cameFrom

protected Map<OVertex,OVertex> cameFrom

gScore

protected Map<OVertex,Double> gScore

fScore

protected Map<OVertex,Double> fScore

open

protected PriorityQueue<OVertex> open

Constructor Details

OSQLFunctionAstar

public OSQLFunctionAstar()

Method Details

execute

public LinkedList<OVertex> 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

getNeighborEdges

protected Set<OEdge> getNeighborEdges(OVertex node)

getSyntax

public String getSyntax()

Description copied from interface: OSQLFunction

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: OSQLFunction

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

Specified by:

getResult in interface OSQLFunction

Overrides:

getResult in class OSQLFunctionAbstract

Returns:

Aggregation result

getDistance

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

Specified by:

getDistance in class OSQLFunctionHeuristicPathFinderAbstract

getDistance

protected double getDistance(OEdge edge)

aggregateResults

public boolean aggregateResults()

Description copied from interface: OSQLFunction

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 obtain by calling OSQLFunction.getResult()

Specified by:

aggregateResults in interface OSQLFunction

Overrides:

aggregateResults in class OSQLFunctionMathAbstract

Returns:

true if function aggregate results

getHeuristicCost

protected double getHeuristicCost(OVertex node,
 OVertex parent,
 OVertex target,
 OCommandContext iContext)

Specified by:

getHeuristicCost in class OSQLFunctionHeuristicPathFinderAbstract

isVariableEdgeWeight

protected boolean isVariableEdgeWeight()

Overrides:

isVariableEdgeWeight in class OSQLFunctionHeuristicPathFinderAbstract