jtp.frame
Class EnumeratingReasoner

java.lang.Object
  |
  +--jtp.frame.EnumeratingReasoner

All Implemented Interfaces:

Reasoner

public class EnumeratingReasoner

extends Object

implements Reasoner

EnumeratingReasoner.java Created: Fri Jan 12 00:38:44 2001

Nested Class Summary

static class

EnumeratingReasoner.ProofStep This intermediate proof step is necessary for the frame system when the query does not have enough variables bound to prove the goal directly.

Constructor Summary

EnumeratingReasoner()

Method Summary

boolean	acceptable(Object o) decides if the goal is suitable for being processed by this reasoner.
ReasoningStepIterator	process(Object o) This method attempts to find proof for the goal.

Methods inherited from class java.lang.Object

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

Constructor Detail

EnumeratingReasoner

public EnumeratingReasoner()

Method Detail

acceptable

public boolean acceptable(Object o)

Description copied from interface: Reasoner

decides if the goal is suitable for being processed by this reasoner. This method should be fast; if there are doubts as to whether a goal is acceptable, and it looks like determining it might take some time, the method should return true and let the process method figure it out.

Example. Many reasoners only process literals with certain predicates and arity. These reasoners will use those criteria to determine acceptability, for example a reasoner dealing with equality could accept goals that are:

1. Literals,
2. have = as their relation predicate,
3. have exactly two arguments.

Specified by:

acceptable in interface Reasoner

Returns:

true if the goal is suitable for this reasoner, false otherwise.

process

public ReasoningStepIterator process(Object o)

Description copied from interface: Reasoner

This method attempts to find proof for the goal. It returns an enumeration of reasoning steps that correspond to alternative proofs for the goal. Consequently, the items of the enumeration can actually belong to different models of the goal sentence, and have incompatible variable assignments.

Example. A reasoner that performs unification of the goal with facts in a knowledge base can return the following enumeration for the goal (parent joe ?x):

1. A reasoning step proving (parent joe fred) with variable assignment ?x=fred,
2. A reasoning step proving (parent joe mary) with variable assignment ?x=mary.

Specified by:

process in interface Reasoner

Parameters:

o - the goal: either a query or an assertion

Returns:

the iterator of reasoning steps - proofs for the query, or consequences of the assertion.