net.ontopia.topicmaps.query.impl.utils

Class PredicateDrivenCostEstimator

java.lang.Object

net.ontopia.topicmaps.query.impl.utils.CostEstimator

net.ontopia.topicmaps.query.impl.utils.PredicateDrivenCostEstimator

public class PredicateDrivenCostEstimator
extends CostEstimator

Field Summary

Fields

Modifier and Type	Field and Description
static int	BIG_RESULT
static int	FAIL_RESULT
static int	FILTER_RESULT
static int	INFINITE_RESULT
static int	MEDIUM_RESULT
static int	SINGLE_RESULT
static int	SMALL_RESULT
static int	WHOLE_TM_RESULT

Constructor Summary

Constructors

Constructor and Description
PredicateDrivenCostEstimator()

Method Summary

Modifier and Type	Method and Description
int	computeCost(Set context, AbstractClause clause, Set literalvars, String rulename) INTERNAL: Computes the cost of evaluating the given clause in the given context of variable bindings.
static int	getComparisonPredicateCost(boolean[] boundparams)

Methods inherited from class java.lang.Object

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

Field Detail

INFINITE_RESULT

public static int INFINITE_RESULT

WHOLE_TM_RESULT

public static int WHOLE_TM_RESULT

BIG_RESULT

public static int BIG_RESULT

MEDIUM_RESULT

public static int MEDIUM_RESULT

SMALL_RESULT

public static int SMALL_RESULT

SINGLE_RESULT

public static int SINGLE_RESULT

FILTER_RESULT

public static int FILTER_RESULT

FAIL_RESULT

public static int FAIL_RESULT

Constructor Detail

PredicateDrivenCostEstimator

public PredicateDrivenCostEstimator()

Method Detail

computeCost

public int computeCost(Set context,
                       AbstractClause clause,
                       Set literalvars,
                       String rulename)

INTERNAL: Computes the cost of evaluating the given clause in the given context of variable bindings. The cost largely depends on the number of unbound variables in the clause.

Specified by:

computeCost in class CostEstimator

Parameters:

context - A set of bound variables.

clause - The clause whose cost we want to compute.

literalvars - Contains the variables representing literals. Only an issue in rules.

rulename - The name of the current rule (so we can delay recursive evaluation).

getComparisonPredicateCost

public static int getComparisonPredicateCost(boolean[] boundparams)