net.ontopia.topicmaps.query.impl.utils
Class SimpleCostEstimator

java.lang.Object
  net.ontopia.topicmaps.query.impl.utils.CostEstimator
      net.ontopia.topicmaps.query.impl.utils.SimpleCostEstimator

public class SimpleCostEstimator
extends CostEstimator

Constructor Summary

SimpleCostEstimator()

Method Summary

int	computeCost(java.util.Set context, AbstractClause clause, java.util.Set literalvars, java.lang.String rulename) INTERNAL: Computes the cost of evaluating the given clause in the given context of variable bindings.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleCostEstimator

public SimpleCostEstimator()

Method Detail

computeCost

public int computeCost(java.util.Set context,
                       AbstractClause clause,
                       java.util.Set literalvars,
                       java.lang.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).