org.projog.core.predicate

Class Predicates

java.lang.Object

org.projog.core.predicate.Predicates

public class Predicates
extends Object

Acts as a repository of rules and facts.

Constructor Summary

Constructors

Constructor and Description
Predicates(KnowledgeBase kb)

Method Summary

Modifier and Type	Method and Description
void	addPredicateFactory(PredicateKey key, PredicateFactory predicateFactory) Associates a PredicateFactory with this KnowledgeBase.
void	addPredicateFactory(PredicateKey key, String predicateFactoryClassName) Associates a PredicateFactory with this KnowledgeBase.
void	addUserDefinedPredicate(UserDefinedPredicateFactory userDefinedPredicate) Adds a user defined predicate to this object.
UserDefinedPredicateFactory	createOrReturnUserDefinedPredicate(PredicateKey key) Returns the UserDefinedPredicateFactory for the specified PredicateKey.
Set<PredicateKey>	getAllDefinedPredicateKeys() Returns details of all predicates, both user-defined and built-in predicates.
Predicate	getPredicate(Term t)
PredicateFactory	getPredicateFactory(PredicateKey key) Returns the PredicateFactory associated with the specified PredicateKey.
PredicateFactory	getPredicateFactory(Term term) Returns the PredicateFactory associated with the specified Term.
PredicateFactory	getPreprocessedPredicateFactory(Term term)
Map<PredicateKey,UserDefinedPredicateFactory>	getUserDefinedPredicates() Returns details of all the user define predicates of this object.

Methods inherited from class java.lang.Object

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

Constructor Detail

Predicates

public Predicates(KnowledgeBase kb)

Method Detail

getPredicate

public Predicate getPredicate(Term t)

getAllDefinedPredicateKeys

public Set<PredicateKey> getAllDefinedPredicateKeys()

Returns details of all predicates, both user-defined and built-in predicates.

getUserDefinedPredicates

public Map<PredicateKey,UserDefinedPredicateFactory> getUserDefinedPredicates()

Returns details of all the user define predicates of this object.

createOrReturnUserDefinedPredicate

public UserDefinedPredicateFactory createOrReturnUserDefinedPredicate(PredicateKey key)

Returns the UserDefinedPredicateFactory for the specified PredicateKey.

If this object does not already have a UserDefinedPredicateFactory for the specified PredicateKey then it will create it.

Throws:

ProjogException - if the specified PredicateKey represents an existing "plugin" predicate

addUserDefinedPredicate

public void addUserDefinedPredicate(UserDefinedPredicateFactory userDefinedPredicate)

Adds a user defined predicate to this object.

Any existing UserDefinedPredicateFactory with the same PredicateKey will be replaced.

Throws:

ProjogException - if the PredicateKey of the specified UserDefinedPredicateFactory represents an existing "plugin" predicate

getPreprocessedPredicateFactory

public PredicateFactory getPreprocessedPredicateFactory(Term term)

getPredicateFactory

public PredicateFactory getPredicateFactory(Term term)

Returns the PredicateFactory associated with the specified Term.

If this object has no PredicateFactory associated with the PredicateKey of the specified Term then a new instance of UnknownPredicate is returned.

getPredicateFactory

public PredicateFactory getPredicateFactory(PredicateKey key)

Returns the PredicateFactory associated with the specified PredicateKey.

If this object has no PredicateFactory associated with the specified PredicateKey then a new instance of UnknownPredicate is returned.

addPredicateFactory

public void addPredicateFactory(PredicateKey key,
                                String predicateFactoryClassName)

Associates a PredicateFactory with this KnowledgeBase.

This method provides a mechanism for "plugging in" or "injecting" implementations of PredicateFactory at runtime. This mechanism provides an easy way to configure and extend the functionality of Projog - including adding functionality not possible to define in pure Prolog syntax.

Parameters:

key - The name and arity to associate the PredicateFactory with.

predicateFactoryClassName - The name of a class that implements PredicateFactory.

Throws:

ProjogException - if there is already a PredicateFactory associated with the PredicateKey

addPredicateFactory

public void addPredicateFactory(PredicateKey key,
                                PredicateFactory predicateFactory)

Associates a PredicateFactory with this KnowledgeBase.

This method provides a mechanism for "plugging in" or "injecting" implementations of PredicateFactory at runtime. This mechanism provides an easy way to configure and extend the functionality of Projog - including adding functionality not possible to define in pure Prolog syntax.

Parameters:

key - The name and arity to associate the PredicateFactory with.

predicateFactory - The PredicateFactory to be added.

Throws:

ProjogException - if there is already a PredicateFactory associated with the PredicateKey