net.sf.tweety.logics.fol.syntax

Class FOLAtom

java.lang.Object

net.sf.tweety.logics.fol.syntax.RelationalFormula

net.sf.tweety.logics.fol.syntax.FolFormula

net.sf.tweety.logics.fol.syntax.FOLAtom

All Implemented Interfaces:

Formula, Atom, ClassicalFormula, ComplexLogicalFormula, Conjuctable, Disjunctable, Invertable, LogicStructure, ProbabilityAware, QuantifiedFormula, SimpleLogicalFormula

public class FOLAtom
extends FolFormula
implements Atom

An atom in first-order logic, i.e. a predicate and a list of argument terms.

Author:

Matthias Thimm

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.tweety.logics.commons.syntax.interfaces.Atom

Atom.AtomImpl, Atom.RETURN_SET_PREDICATE

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.List<Term<?>>	arguments The arguments of the atom
private Predicate	predicate The predicate of this atom

Constructor Summary

Constructors

Constructor and Description
FOLAtom() Default-Ctor: Creates new empty FOL-Atom
FOLAtom(FOLAtom other)
FOLAtom(Predicate predicate) Creates a new atom with the given predicate and initializes an empty argument list.
FOLAtom(Predicate predicate, java.util.List<? extends Term<?>> arguments) Creates a new atom with the given predicate and list of terms
FOLAtom(Predicate predicate, Term<?>... terms)

Method Summary

Modifier and Type	Method and Description
void	addArgument(Term<?> term) Appends the given argument to this atom's arguments and returns itself.
FOLAtom	clone() Creates a deep copy of this formula
FolFormula	collapseAssociativeFormulas() This method collapses all associative operations appearing in this term, e.g.
boolean	containsQuantifier() Checks whether this formula contains any quantification.
boolean	equals(java.lang.Object obj)
java.util.List<Term<?>>	getArguments()
java.util.Set<FOLAtom>	getAtoms() Processes the set of all atoms which appear in this formula
java.util.Set<Functor>	getFunctors()
java.lang.String	getName()
Predicate	getPredicate() Returns the predicate of this atom
java.util.Set<Predicate>	getPredicates() Processes the set of all predicates which appear in 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.
java.util.Set<Variable>	getUnboundVariables()
int	hashCode()
boolean	isClosed() Checks whether this formula is closed, i.e.
boolean	isClosed(java.util.Set<Variable> boundVariables) Checks whether this formula is closed, i.e.
boolean	isComplete() Checks whether this atom is complete, i.e.
boolean	isDnf() Checks whether this formula is in disjunctive normal form.
boolean	isLiteral()
boolean	isWellBound() Checks whether this formula is well-bound, i.e.
boolean	isWellBound(java.util.Set<Variable> boundVariables) Checks whether this formula is well-bound, i.e.
Atom.RETURN_SET_PREDICATE	setPredicate(Predicate newer) Changes the predicate of the atom.
FOLAtom	substitute(Term<?> v, Term<?> t) Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula.
FolFormula	toNnf() Makes the negation normal form of this formula.
java.lang.String	toString()

Methods inherited from class net.sf.tweety.logics.fol.syntax.FolFormula

combineWithAnd, combineWithOr, complement, getQuantifierVariables, getUniformProbability, toDnf

Methods inherited from class net.sf.tweety.logics.fol.syntax.RelationalFormula

allGroundInstances, allSubstitutions, containsTermsOfType, exchange, getFormula, getPredicateCls, getSatisfactionRatio, getSignature, isGround, 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.SimpleLogicalFormula

getPredicateCls

Methods inherited from interface net.sf.tweety.commons.Formula

getSignature

Field Detail

predicate

private Predicate predicate

The predicate of this atom

arguments

private java.util.List<Term<?>> arguments

The arguments of the atom

Constructor Detail

FOLAtom

public FOLAtom()

Default-Ctor: Creates new empty FOL-Atom

FOLAtom

public FOLAtom(Predicate predicate)

Creates a new atom with the given predicate and initializes an empty argument list.

Parameters:

predicate - the predicate of the atom.

FOLAtom

public FOLAtom(Predicate predicate,
               Term<?>... terms)

FOLAtom

public FOLAtom(Predicate predicate,
               java.util.List<? extends Term<?>> arguments)

Creates a new atom with the given predicate and list of terms

Parameters:

predicate - the predicate of the atom

arguments - the arguments (terms) of the atom

FOLAtom

public FOLAtom(FOLAtom other)

Method Detail

addArgument

public void addArgument(Term<?> term)
                 throws java.lang.IllegalArgumentException

Appends the given argument to this atom's arguments and returns itself.

Specified by:

addArgument in interface Atom

Parameters:

term - an argument to be added

Throws:

java.lang.IllegalArgumentException - if the given term does not correspond to the expected sort or the argument list is complete.

substitute

public FOLAtom substitute(Term<?> v,
                          Term<?> t)
                   throws java.lang.IllegalArgumentException

Description copied from class: RelationalFormula

Substitutes all occurrences of term "v" in this formula by term "t" and returns the new formula. NOTE: if "v" is a variable and bound to a quantifier then "v" is not substituted in that quantifiers inner formula.

Specified by:

substitute in interface ComplexLogicalFormula

Specified by:

substitute in class FolFormula

Parameters:

v - the term to be substituted.

t - the term to substitute.

Returns:

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

Throws:

java.lang.IllegalArgumentException - if "v" and "t" are of different sorts (NOTE: this exception is only thrown when "v" actually appears in this formula).

getAtoms

public java.util.Set<FOLAtom> 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 RelationalFormula

Returns:

all atoms that appear in this formula.

isComplete

public boolean isComplete()

Checks whether this atom is complete, i.e. whether every argument is set.

Specified by:

isComplete in interface Atom

Returns:

"true" if the atom is complete.

getUnboundVariables

public java.util.Set<Variable> getUnboundVariables()

Specified by:

getUnboundVariables in interface QuantifiedFormula

Returns:

a set of of unbound variables

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

Returns:

all predicates that appear in this formula

getFunctors

public java.util.Set<Functor> getFunctors()

Specified by:

getFunctors in class RelationalFormula

Returns:

all functor that appear in this formula.

isClosed

public boolean isClosed()

Description copied from interface: QuantifiedFormula

Checks whether this formula is closed, i.e. whether every variables occurring in the formula is bound by a quantifier.

Specified by:

isClosed in interface QuantifiedFormula

Returns:

"true" if this formula is closed, "false" otherwise.

isClosed

public boolean isClosed(java.util.Set<Variable> boundVariables)

Description copied from interface: QuantifiedFormula

Checks whether this formula is closed, i.e. whether every variables occurring in the formula is bound by a quantifier. Every variable in "boundVariables" is already assumed to be bound.

Specified by:

isClosed in interface QuantifiedFormula

Parameters:

boundVariables - the variables assumed to be bound.

Returns:

"true" if this formula is closed wrt. "boundVariables", "false" otherwise.

isWellBound

public boolean isWellBound()

Description copied from interface: QuantifiedFormula

Checks whether this formula is well-bound, i.e. whether no variable bound by a quantifier is again bound by another quantifier within the first quantifier's range.

Specified by:

isWellBound in interface QuantifiedFormula

Returns:

"true" if this formula is well-bound, "false" otherwise.

isWellBound

public boolean isWellBound(java.util.Set<Variable> boundVariables)

Description copied from interface: QuantifiedFormula

Checks whether this formula is well-bound, i.e. whether no variable bound by a quantifier is again bound by another quantifier within the first quantifier range. Every variable in "boundVariables" is assumed to be bound already.

Specified by:

isWellBound in interface QuantifiedFormula

Parameters:

boundVariables - the variables assumed to be bound.

Returns:

"true" if this formula is well-bound, "false" otherwise.

containsQuantifier

public boolean containsQuantifier()

Description copied from interface: QuantifiedFormula

Checks whether this formula contains any quantification.

Specified by:

containsQuantifier in interface QuantifiedFormula

Returns:

"true" if this formula contains a quantification.

getPredicate

public Predicate getPredicate()

Returns the predicate of this atom

Specified by:

getPredicate in interface Atom

Returns:

the predicate of this atom

getArguments

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

Specified by:

getArguments in interface Atom

Returns:

the arguments of this atom.

isDnf

public boolean isDnf()

Description copied from class: FolFormula

Checks whether this formula is in disjunctive normal form.

Specified by:

isDnf in class FolFormula

Returns:

"true" iff this formula is in disjunctive normal form.

isLiteral

public boolean isLiteral()

Specified by:

isLiteral in interface SimpleLogicalFormula

Returns:

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

toString

public java.lang.String toString()

Specified by:

toString in class RelationalFormula

toNnf

public FolFormula toNnf()

Description copied from class: FolFormula

Makes the negation normal form of this formula.

Specified by:

toNnf in class FolFormula

Returns:

the NNF of this formula

collapseAssociativeFormulas

public FolFormula collapseAssociativeFormulas()

Description copied from class: FolFormula

This method collapses all associative operations appearing in this term, e.g. every a||(b||c) becomes a||b||c.

Specified by:

collapseAssociativeFormulas in class FolFormula

Returns:

the collapsed formula.

hashCode

public int hashCode()

Specified by:

hashCode in interface SimpleLogicalFormula

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface SimpleLogicalFormula

Overrides:

equals in class java.lang.Object

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

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

clone

public FOLAtom 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 FolFormula

setPredicate

public Atom.RETURN_SET_PREDICATE setPredicate(Predicate newer)

Description copied from interface: Atom

Changes the predicate of the atom. Given an old Predicate po and a new predicate pn with their list of arguments types at(po) and at(pn) and the arguments of this Atom: arg(this) this method distinguishes between three cases: 1. The predicate only differ in the names, returning RSP_SUCCESS 2. The old predicates argument types is a sub-list of the new argument types then the method returns RSP_INCOMPLETE and the atoms isComplete() method returns false 3. The new predicates argument types is a sub-list of the old argument types then the method returns RSP_TRUNCATED and the arguments of this atom are truncated too and isComplete() returns true. 4. The old and new predicates' argument types differ then the list of arguments of the atom get cleared and isComplete() returns false.

Specified by:

setPredicate in interface Atom

Returns:

Depends on the cases described above: 1. RSP_SUCCESS 2. RSP_INCOMPLETE 3. RSP_TRUNCATED 4. RSP_CLEARED

getName

public java.lang.String getName()

Specified by:

getName in interface Atom

Returns:

the name of the predicate