Class InterpretedTailRecursivePredicateFactory

java.lang.Object
org.projog.core.predicate.udp.InterpretedTailRecursivePredicateFactory
All Implemented Interfaces:
PredicateFactory
public final class InterpretedTailRecursivePredicateFactory extends Object implements PredicateFactory
Creates "tail recursion optimised" versions of user defined predicates.

Each instance of InterpretedTailRecursivePredicateFactory creates new instances of InterpretedTailRecursivePredicate for a specific user defined predicate. The user defined predicate must be judged as eligible for tail recursion optimisation using the criteria used by TailRecursivePredicateMetaData.

See Also:

  • Field Details

    • spyPoint

      private final SpyPoints.SpyPoint spyPoint

    • metaData

      private final TailRecursivePredicateMetaData metaData

    • firstClausePredicateFactories

      private final PredicateFactory[] firstClausePredicateFactories

    • firstClauseConsequentArgs

      private final Term[] firstClauseConsequentArgs

    • firstClauseOriginalTerms

      private final Term[] firstClauseOriginalTerms

    • secondClausePredicateFactories

      private final PredicateFactory[] secondClausePredicateFactories

    • secondClauseConsequentArgs

      private final Term[] secondClauseConsequentArgs

    • secondClauseOriginalTerms

      private final Term[] secondClauseOriginalTerms

  • Constructor Details

  • Method Details

    • getPredicate

      public InterpretedTailRecursivePredicate 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:

    • isRetryable

      private boolean isRetryable(Term[] args)

    • getSpyPoint

      private static SpyPoints.SpyPoint getSpyPoint(KnowledgeBase kb, TailRecursivePredicateMetaData metaData)

    • 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