Package net.sf.tweety.lp.asp.syntax

Class ASPRule

java.lang.Object

net.sf.tweety.lp.asp.syntax.ASPElement

net.sf.tweety.lp.asp.syntax.ASPRule

All Implemented Interfaces:

java.lang.Comparable<ASPRule>, Formula, Rule<ASPHead,ASPBodyElement>, ComplexLogicalFormula, LogicStructure, SimpleLogicalFormula

public class ASPRule
extends ASPElement
implements Rule<ASPHead,ASPBodyElement>, java.lang.Comparable<ASPRule>

This class models a rule in ASP. A rule consists of a head and a body. The head contains n>=0 classical atoms and the body contains n>=0 literals. Rules with non-empty heads and empty bodies are called facts, rules with empty heads and non-empty bodies are called constraints.

Author:

Anna Gessler, Tim Janus, Thomas Vengels

Constructor Summary

Constructors

Constructor	Description
ASPRule()	Empty constructor
ASPRule(java.util.List<ASPBodyElement> body)	Creates a constraint with the given body.
ASPRule(java.util.List<ASPBodyElement> nafliterals, Term<?> weight, java.util.List<Term<?>> terms)	Creates a constraint with the given weight and terms.
ASPRule(java.util.List<ASPBodyElement> body, Term<?> weight, Term<?> level, java.util.List<Term<?>> terms)	Creates a constraint with the given weight, level and terms.
ASPRule(ASPHead head)	Creates a fact with the given ASPHead.
ASPRule(ASPHead head, java.util.List<ASPBodyElement> body)	Creates a rule with the given head and body.
ASPRule(ASPLiteral literal)	Creates a fact with the given literal.
ASPRule(ASPLiteral head, java.util.List<ASPBodyElement> body)	Creates a rule with the given head and body.
ASPRule(ASPLiteral head, ASPBodyElement b)	Creates a rule with the given head and a single-element body.
ASPRule(ASPRule other)	Copy-Constructor

Method Summary

Modifier and Type	Method	Description
void	addPremise(ASPBodyElement premise)
void	addPremises(java.util.Collection<? extends ASPBodyElement> premises)
void	addToHead(ASPLiteral h)
ASPRule	clone()	Creates a deep copy of this formula
int	compareTo(ASPRule arg0)
boolean	equals(java.lang.Object other)
ASPRule	exchange(Term<?> v, Term<?> t)	Substitutes all occurrences of term "v" in this formula by term "t" and at the same time replaces all occurrences of term "t" by term "v" and eventually returns the new formula.
java.util.Set<ASPAtom>	getAtoms()	Processes the set of all atoms which appear in this formula
java.util.List<ASPBodyElement>	getBody()
ASPHead	getConclusion()	Returns the conclusion of this rule.
java.util.List<Term<?>>	getConstraintTerms()
ASPHead	getHead()
Term<?>	getLevel()
java.util.Collection<? extends ASPLiteral>	getLiterals()
java.util.Set<Predicate>	getPredicates()	Processes the set of all predicates which appear in this formula
java.util.List<ASPBodyElement>	getPremise()	Returns the premise of this rule.
FolSignature	getSignature()	Returns the signature of the language of this formula.
java.util.Set<Term<?>>	getTerms()
<C extends Term<?>> java.util.Set<C>	getTerms(java.lang.Class<C> cls)	Processes the set containing all terms of type C.
Term<?>	getWeight()
int	hashCode()
boolean	isConstraint()
boolean	isEmpty()
boolean	isFact()
boolean	isGround()	Checks whether this formula is ground, i.e.
boolean	isLiteral()
java.lang.Boolean	isSafe()	This methods tests a rule for safety.
void	setBody(java.util.List<ASPBodyElement> body)
void	setConclusion(ASPHead conclusion)
void	setConclusion(ASPLiteral head)
void	setHead(ASPHead head)
void	setLevel(Term<?> level)
void	setWeight(Term<?> weight)
ASPRule	substitute(Term<?> v, Term<?> t)	Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula.
java.lang.String	toString()

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

containsTermsOfType, getPredicateCls, isWellFormed, substitute

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ASPRule

public ASPRule()

Empty constructor

ASPRule

public ASPRule(ASPHead head)

Creates a fact with the given ASPHead.

Parameters:

head - an ASPHead

ASPRule

public ASPRule(ASPLiteral literal)

Creates a fact with the given literal.

Parameters:

literal - a literal

ASPRule

public ASPRule(ASPHead head,
               java.util.List<ASPBodyElement> body)

Creates a rule with the given head and body.

Parameters:

head - an ASPHead

body - a list of ASPBodyElement

ASPRule

public ASPRule(ASPLiteral head,
               ASPBodyElement b)

Creates a rule with the given head and a single-element body.

Parameters:

head - an ASPLiteral

b - a body element

ASPRule

public ASPRule(ASPLiteral head,
               java.util.List<ASPBodyElement> body)

Creates a rule with the given head and body.

Parameters:

head - an ASPLiteral

body - a list of ASPBodyElement

ASPRule

public ASPRule(java.util.List<ASPBodyElement> body)

Creates a constraint with the given body.

Parameters:

body - a list of ASPBodyElement

ASPRule

public ASPRule(java.util.List<ASPBodyElement> nafliterals,
               Term<?> weight,
               java.util.List<Term<?>> terms)

Creates a constraint with the given weight and terms.

Parameters:

nafliterals - the naf literals

weight - some weight

terms - a list of terms

ASPRule

public ASPRule(java.util.List<ASPBodyElement> body,
               Term<?> weight,
               Term<?> level,
               java.util.List<Term<?>> terms)

Creates a constraint with the given weight, level and terms.

Parameters:

body - a list of ASPBodyElement

weight - a term

level - a term

terms - a list of terms

ASPRule

public ASPRule(ASPRule other)

Copy-Constructor

Parameters:

other - another ASPRule

Method Detail

isSafe

public java.lang.Boolean isSafe()

This methods tests a rule for safety. Safety is defined as follows in the ASP-Core-2 standard: A rule, weak constraint or query is safe, if the set V of global variables

Returns:

true if the rule is safe, false otherwise

isFact

public boolean isFact()

Specified by:

isFact in interface Rule<ASPHead,ASPBodyElement>

isConstraint

public boolean isConstraint()

Specified by:

isConstraint in interface Rule<ASPHead,ASPBodyElement>

addPremises

public void addPremises(java.util.Collection<? extends ASPBodyElement> premises)

Specified by:

addPremises in interface Rule<ASPHead,ASPBodyElement>

getSignature

public FolSignature getSignature()

Description copied from interface: Formula

Returns the signature of the language of this formula.

Specified by:

getSignature in interface Formula

Specified by:

getSignature in interface Rule<ASPHead,ASPBodyElement>

Specified by:

getSignature in class ASPElement

Returns:

the signature of the language of this formula.

setConclusion

public void setConclusion(ASPHead conclusion)

Specified by:

setConclusion in interface Rule<ASPHead,ASPBodyElement>

setConclusion

public void setConclusion(ASPLiteral head)

addPremise

public void addPremise(ASPBodyElement premise)

Specified by:

addPremise in interface Rule<ASPHead,ASPBodyElement>

getPremise

public java.util.List<ASPBodyElement> getPremise()

Description copied from interface: Rule

Returns the premise of this rule.

Specified by:

getPremise in interface Rule<ASPHead,ASPBodyElement>

Returns:

the premise of this rule.

getConclusion

public ASPHead getConclusion()

Description copied from interface: Rule

Returns the conclusion of this rule.

Specified by:

getConclusion in interface Rule<ASPHead,ASPBodyElement>

Returns:

the conclusion of this rule.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getWeight

public Term<?> getWeight()

setWeight

public void setWeight(Term<?> weight)

getLevel

public Term<?> getLevel()

setLevel

public void setLevel(Term<?> level)

getHead

public ASPHead getHead()

setHead

public void setHead(ASPHead head)

addToHead

public void addToHead(ASPLiteral h)

getBody

public java.util.List<ASPBodyElement> getBody()

setBody

public void setBody(java.util.List<ASPBodyElement> body)

getConstraintTerms

public java.util.List<Term<?>> getConstraintTerms()

isGround

public boolean isGround()

Description copied from interface: ComplexLogicalFormula

Checks whether this formula is ground, i.e. whether there appears no variable in this formula.

Specified by:

isGround in interface ComplexLogicalFormula

Overrides:

isGround in class ASPElement

Returns:

"true" if this formula is ground.

compareTo

public int compareTo(ASPRule arg0)

Specified by:

compareTo in interface java.lang.Comparable<ASPRule>

getLiterals

public java.util.Collection<? extends ASPLiteral> getLiterals()

substitute

public ASPRule substitute(Term<?> v,
                          Term<?> t)

Description copied from interface: ComplexLogicalFormula

Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula.

Specified by:

substitute in interface ComplexLogicalFormula

Specified by:

substitute in class ASPElement

Parameters:

v - the term to be substituted.

t - the term to substitute.

Returns:

a formula where every occurrence of "v" is replaced by "t".

exchange

public ASPRule exchange(Term<?> v,
                        Term<?> t)

Description copied from interface: ComplexLogicalFormula

Substitutes all occurrences of term "v" in this formula by term "t" and at the same time replaces all occurrences of term "t" by term "v" and eventually returns the new formula.

Specified by:

exchange in interface ComplexLogicalFormula

Overrides:

exchange in class ASPElement

Parameters:

v - a term.

t - a term.

Returns:

a new logical formula with both "v" and "t" exchanged.

isLiteral

public boolean isLiteral()

Specified by:

isLiteral in interface SimpleLogicalFormula

Returns:

true if the formula represents a literal in the language or false otherwise

getTerms

public java.util.Set<Term<?>> getTerms()

Specified by:

getTerms in interface LogicStructure

Returns:

a set containing all terms of this logical structure

getTerms

public <C extends Term<?>> java.util.Set<C> getTerms(java.lang.Class<C> cls)

Description copied from interface: LogicStructure

Processes the set containing all terms of type C. This method uses the equals method of the given Class and therefore does not add terms which are sub classes of type C to the set.

Specified by:

getTerms in interface LogicStructure

Type Parameters:

C - the type of terms

Parameters:

cls - The Class structure containing type information about the searched term

Returns:

A set containing all terms of type C of this logical structure

getPredicates

public java.util.Set<Predicate> getPredicates()

Description copied from interface: SimpleLogicalFormula

Processes the set of all predicates which appear in this formula

Specified by:

getPredicates in interface SimpleLogicalFormula

Specified by:

getPredicates in class ASPElement

Returns:

all predicates that appear in this formula

getAtoms

public java.util.Set<ASPAtom> getAtoms()

Description copied from interface: SimpleLogicalFormula

Processes the set of all atoms which appear in this formula

Specified by:

getAtoms in interface SimpleLogicalFormula

Specified by:

getAtoms in class ASPElement

Returns:

The set of all atoms

clone

public ASPRule clone()

Description copied from interface: SimpleLogicalFormula

Creates a deep copy of this formula

Specified by:

clone in interface ComplexLogicalFormula

Specified by:

clone in interface SimpleLogicalFormula

Specified by:

clone in class ASPElement

Returns:

the cloned formula

equals

public boolean equals(java.lang.Object other)

Specified by:

equals in interface SimpleLogicalFormula

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface SimpleLogicalFormula

Overrides:

hashCode in class java.lang.Object

isEmpty

public boolean isEmpty()

Returns:

true if the rule's head and body are both empty, false otherwise.