Class Between

java.lang.Object

org.projog.core.predicate.builtin.compare.Between

All Implemented Interfaces:

PredicateFactory

public final class Between
extends Object
implements PredicateFactory

between(X,Y,Z) - checks if a number is within a specified range.

between(X,Y,Z) succeeds if the integer numeric value represented by Z is greater than or equal to the integer numeric value represented by X and is less than or equal to the integer numeric value represented by Y.

If Z is an uninstantiated variable then Z will be successively unified with all integer values in the range from X to Y.

Constructor Summary

Constructors

Constructor	Description
Between(KnowledgeBase kb)

Method Summary

Modifier and Type	Method	Description
Predicate	getPredicate(Term term)	Returns a Predicate to be used in the evaluation of a goal.
boolean	isRetryable()	Should instances of this implementation be re-evaluated when backtracking?

Methods inherited from class Object

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

Methods inherited from interface PredicateFactory

isAlwaysCutOnBacktrack, preprocess

Constructor Details

Between

public Between(KnowledgeBase kb)

Method Details

getPredicate

public Predicate getPredicate(Term term)

Description copied from interface: PredicateFactory

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

Specified by:

getPredicate in interface PredicateFactory

Parameters:

term - the term containing 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()

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