net.sf.tweety.lp.asp.syntax

Class Rule

java.lang.Object

net.sf.tweety.logics.commons.syntax.ComplexLogicalFormulaAdapter

net.sf.tweety.lp.asp.syntax.DLPElementAdapter

net.sf.tweety.lp.asp.syntax.Rule

All Implemented Interfaces:

Comparable<Rule>, net.sf.tweety.commons.Formula, net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>, net.sf.tweety.logics.commons.syntax.interfaces.ComplexLogicalFormula, net.sf.tweety.logics.commons.syntax.interfaces.LogicStructure, net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula, DLPElement

public class Rule
extends DLPElementAdapter
implements Comparable<Rule>, DLPElement, net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

This class models a rule for a disjunctive logic program. A rule is a collection of literals and more sophisticated rule elements like Aggregate or Arithmetic. It uses separate lists for the head and the body. It also implements the Comparable interface to allow the ordering in collections.

Author:

Tim Janus, Thomas Vengels

Constructor Summary

Constructors

Constructor and Description
Rule() Default-Ctor: Creates an empty rule without any head literals or body elements
Rule(DLPHead head) Ctor: Create a rule with the given head, cause there are no body elements the created rule is a fact.
Rule(DLPLiteral head) Ctor: Create a rule with the given head, cause there are no body elements the created rule is a fact.
Rule(DLPLiteral head, DLPElement body)
Rule(DLPLiteral head, List<DLPElement> litsBody)
Rule(List<DLPLiteral> litsHead, List<DLPElement> litsBody)
Rule(Rule other) Copy-Ctor: Makes a deep copy of the given rule
Rule(String ruleexpr)

Method Summary

Modifier and Type	Method and Description
void	addPremise(DLPElement premise)
void	addPremises(Collection<? extends DLPElement> premises)
Rule	clone()
int	compareTo(Rule arg0)
boolean	equals(Object other)
Set<DLPAtom>	getAtoms()
DLPHead	getConclusion()
SortedSet<DLPLiteral>	getLiterals()
Set<DLPPredicate>	getPredicates()
Collection<DLPElement>	getPremise()
net.sf.tweety.logics.fol.syntax.FolSignature	getSignature()
Set<net.sf.tweety.logics.commons.syntax.interfaces.Term<?>>	getTerms()
int	hashCode()
boolean	isConstraint()
boolean	isFact()
boolean	isSafe() Proofs if the given rule is safe for use in a solver.
void	setConclusion(DLPHead conclusion)
void	setConclusion(DLPLiteral literal)
Rule	substitute(net.sf.tweety.logics.commons.syntax.interfaces.Term<?> v, net.sf.tweety.logics.commons.syntax.interfaces.Term<?> t)
String	toString()

Methods inherited from class net.sf.tweety.lp.asp.syntax.DLPElementAdapter

getPredicateCls

Methods inherited from class net.sf.tweety.logics.commons.syntax.ComplexLogicalFormulaAdapter

containsTermsOfType, exchange, getTerms, isGround, isLiteral, isWellFormed, substitute

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.tweety.logics.commons.syntax.interfaces.ComplexLogicalFormula

exchange, isGround, isWellFormed, substitute

Methods inherited from interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

getPredicateCls, isLiteral

Methods inherited from interface net.sf.tweety.logics.commons.syntax.interfaces.LogicStructure

containsTermsOfType, getTerms

Constructor Detail

Rule

public Rule()

Default-Ctor: Creates an empty rule without any head literals or body elements

Rule

public Rule(Rule other)

Copy-Ctor: Makes a deep copy of the given rule

Rule

public Rule(DLPHead head)

Ctor: Create a rule with the given head, cause there are no body elements the created rule is a fact.

Parameters:

head - The head of the rule as ELPHead

Rule

public Rule(DLPLiteral head)

Ctor: Create a rule with the given head, cause there are no body elements the created rule is a fact.

Parameters:

head - The head of the rule as ELPLiteral

Rule

public Rule(DLPLiteral head,
            DLPElement body)

Rule

public Rule(DLPLiteral head,
            List<DLPElement> litsBody)

Rule

public Rule(List<DLPLiteral> litsHead,
            List<DLPElement> litsBody)

Rule

public Rule(String ruleexpr)

Method Detail

getLiterals

public SortedSet<DLPLiteral> getLiterals()

Specified by:

getLiterals in interface DLPElement

Returns:

all the literals used in the rule element

isFact

public boolean isFact()

Specified by:

isFact in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

isConstraint

public boolean isConstraint()

Specified by:

isConstraint in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

isSafe

public boolean isSafe()

Proofs if the given rule is safe for use in a solver. To get a felling when a rule is safe read the following text from the dlv documentation: A variable X in an aggregate-free rule is safe if at least one of the following conditions is satisfied: X occurs in a positive standard predicate in the body of the rule; X occurs in a true negated standard predicate in the body of the rule; X occurs in the last argument of an arithmetic predicate A and all other arguments of A are safe. (*not supported yet) A rule is safe if all its variables are safe. However, cyclic dependencies are disallowed, e.g., :- #succ(X,Y), #succ(Y,X) is not safe.

Returns:

true if the rule is safe considering the above conditions, false otherwise.

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object other)

Specified by:

equals in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Overrides:

equals in class Object

hashCode

public int hashCode()

Specified by:

hashCode in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Overrides:

hashCode in class Object

compareTo

public int compareTo(Rule arg0)

Specified by:

compareTo in interface Comparable<Rule>

clone

public Rule clone()

Specified by:

clone in interface net.sf.tweety.logics.commons.syntax.interfaces.ComplexLogicalFormula

Specified by:

clone in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

clone in interface DLPElement

Specified by:

clone in class DLPElementAdapter

getSignature

public net.sf.tweety.logics.fol.syntax.FolSignature getSignature()

Specified by:

getSignature in interface net.sf.tweety.commons.Formula

Specified by:

getSignature in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

Specified by:

getSignature in interface DLPElement

getPremise

public Collection<DLPElement> getPremise()

Specified by:

getPremise in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

getConclusion

public DLPHead getConclusion()

Specified by:

getConclusion in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

substitute

public Rule substitute(net.sf.tweety.logics.commons.syntax.interfaces.Term<?> v,
                       net.sf.tweety.logics.commons.syntax.interfaces.Term<?> t)
                throws IllegalArgumentException

Specified by:

substitute in interface net.sf.tweety.logics.commons.syntax.interfaces.ComplexLogicalFormula

Specified by:

substitute in interface DLPElement

Throws:

IllegalArgumentException

getAtoms

public Set<DLPAtom> getAtoms()

Specified by:

getAtoms in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

getAtoms in interface DLPElement

getPredicates

public Set<DLPPredicate> getPredicates()

Specified by:

getPredicates in interface net.sf.tweety.logics.commons.syntax.interfaces.SimpleLogicalFormula

Specified by:

getPredicates in interface DLPElement

getTerms

public Set<net.sf.tweety.logics.commons.syntax.interfaces.Term<?>> getTerms()

Specified by:

getTerms in interface net.sf.tweety.logics.commons.syntax.interfaces.LogicStructure

setConclusion

public void setConclusion(DLPHead conclusion)

Specified by:

setConclusion in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

setConclusion

public void setConclusion(DLPLiteral literal)

addPremise

public void addPremise(DLPElement premise)

Specified by:

addPremise in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>

addPremises

public void addPremises(Collection<? extends DLPElement> premises)

Specified by:

addPremises in interface net.sf.tweety.commons.util.rules.Rule<DLPHead,DLPElement>