jdrew.oo.bu
Class Subsumption

java.lang.Object
  jdrew.oo.bu.Subsumption

public class Subsumption
extends java.lang.Object

This class is used for checking if one (newly selected) fact is subsumed by another fact that has already been processed. Subsumption checking is a two step process; first the newly selected fact is ground (all variables are bound to newly created constants), once the fact has been made ground then subsumption is checked by attempting to unify the ground atom with other facts; if unification succeedes then the fact it was unified wtih subsumes the fact that was made ground.

Title: OO jDREW

Description: Reasoning Engine for the Semantic Web - Supporting OO RuleML 0.88

Copyright: Copyright (c) 2005

Constructor Summary

Subsumption(DefiniteClause base)
This creates a subsumption checker; First it initializes all data structures based upon the fact that is passed (this is the one to be checked if it is subsumed by another fact); then it will call the ground(Term) method to ground the fact.

Method Summary

boolean

subsumedBy(DefiniteClause oldfact) This method is called to check to see if the passed fact subsumes the fact that was used in the consturctor of the Subsumption object.

Methods inherited from class java.lang.Object

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

Constructor Detail

Subsumption

public Subsumption(DefiniteClause base)

This creates a subsumption checker; First it initializes all data structures based upon the fact that is passed (this is the one to be checked if it is subsumed by another fact); then it will call the ground(Term) method to ground the fact.

Parameters:

base - DefiniteClause The fact to check for subsumption; this is generally a newly selected fact in the runForwardReasoner method of a ForwardReasoner object.

Method Detail

subsumedBy

public boolean subsumedBy(DefiniteClause oldfact)

This method is called to check to see if the passed fact subsumes the fact that was used in the consturctor of the Subsumption object. This method can be called multiple times to check the newly selcted fact for subsumption by more than one old processed fact.

Parameters:

oldfact - DefiniteClause The old fact to test for subsumption with.

Returns:

boolean returns true if the passed fact subsums the fact given to the constructor; false otherwise.