Class SingleNonRetryableRulePredicateFactory

java.lang.Object

org.projog.core.predicate.udp.SingleNonRetryableRulePredicateFactory

All Implemented Interfaces:

PredicateFactory, PreprocessablePredicateFactory

final class SingleNonRetryableRulePredicateFactory
extends Object
implements PreprocessablePredicateFactory

Field Summary

Fields

Modifier and Type	Field	Description
private final ClauseAction	clause
private final SpyPoints.SpyPoint	spyPoint

Constructor Summary

Constructors

Constructor	Description
SingleNonRetryableRulePredicateFactory(ClauseAction clause, SpyPoints.SpyPoint spyPoint)

Method Summary

Modifier and Type	Method	Description
(package private) static Predicate	evaluateClause(ClauseAction clause, SpyPoints.SpyPoint spyPoint, Term[] args)
Predicate	getPredicate(Term[] args)	Returns a Predicate to be used in the evaluation of a goal.
boolean	isRetryable()	Should instances of this implementation be re-evaluated when backtracking?
PredicateFactory	preprocess(Term arg)

Methods inherited from class Object

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

Methods inherited from interface PredicateFactory

isAlwaysCutOnBacktrack

Field Details

clause

private final ClauseAction clause

spyPoint

private final SpyPoints.SpyPoint spyPoint

Constructor Details

SingleNonRetryableRulePredicateFactory

SingleNonRetryableRulePredicateFactory(ClauseAction clause,
 SpyPoints.SpyPoint spyPoint)

Method Details

getPredicate

public Predicate getPredicate(Term[] args)

Description copied from interface: PredicateFactory

Returns a Predicate to be used in the evaluation of a goal.

Specified by:

getPredicate in interface PredicateFactory

Parameters:

args - the arguments to use in the evaluation of the goal

Returns:

Predicate to be used in the evaluation of the goal

See Also:

• Predicate.evaluate()

evaluateClause

static Predicate evaluateClause(ClauseAction clause,
 SpyPoints.SpyPoint spyPoint,
 Term[] args)

isRetryable

public boolean isRetryable()

Description copied from interface: PredicateFactory

Should instances of this implementation be re-evaluated when backtracking?

Some goals (e.g. X is 1) are only meant to be evaluated once (the statement is either true or false) while others (e.g. repeat(3)) are meant to be evaluated multiple times. For instances of Predicate that are designed to possibly have Predicate.evaluate() called on them multiple times for the same individual query this method should return true. For instances of Predicate that are designed to only be evaluated once per individual query this method should return false.

Specified by:

isRetryable in interface PredicateFactory

Returns:

true if an attempt should be made to re-evaluate instances of implementing classes when backtracking, false otherwise

preprocess

public PredicateFactory preprocess(Term arg)

Specified by:

preprocess in interface PreprocessablePredicateFactory