Package org.projog.core.predicate.builtin.list

Class MapList

java.lang.Object

org.projog.core.predicate.builtin.list.MapList

All Implemented Interfaces:

KnowledgeBaseConsumer, PredicateFactory, PreprocessablePredicateFactory

public final class MapList
extends java.lang.Object
implements PredicateFactory, PreprocessablePredicateFactory, KnowledgeBaseConsumer

maplist(X,Y) / maplist(X,Y,Z) - determines if a goal succeeds against elements of a list.

maplist(X,Y) succeeds if the goal X can be successfully applied to each elements of the list Y.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	MapList.PreprocessedMapList
private static class	MapList.Retryable

Field Summary

Fields

Modifier and Type	Field	Description
private Predicates	predicates

Constructor Summary

Constructors

Constructor	Description
MapList()

Method Summary

Modifier and Type	Method	Description
private static Predicate	getMapListPredicate(PredicateFactory pf, Term[] input)
Predicate	getPredicate(Term[] input)	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 input)
void	setKnowledgeBase(KnowledgeBase kb)	Provides a reference to a KnowledgeBase.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.projog.core.predicate.PredicateFactory

isAlwaysCutOnBacktrack

Field Detail

predicates

private Predicates predicates

Constructor Detail

MapList

public MapList()

Method Detail

setKnowledgeBase

public void setKnowledgeBase(KnowledgeBase kb)

Description copied from interface: KnowledgeBaseConsumer

Provides a reference to a KnowledgeBase.

Specified by:

setKnowledgeBase in interface KnowledgeBaseConsumer

preprocess

public PredicateFactory preprocess(Term input)

Specified by:

preprocess in interface PreprocessablePredicateFactory

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

getPredicate

public Predicate getPredicate(Term[] input)

Description copied from interface: PredicateFactory

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

Specified by:

getPredicate in interface PredicateFactory

Parameters:

input - 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()

getMapListPredicate

private static Predicate getMapListPredicate(PredicateFactory pf,
                                             Term[] input)