de.uni_tuebingen.sfb.lichtenstein.formulas
Class NaryJunctor

java.lang.Object
  de.uni_tuebingen.sfb.lichtenstein.formulas.FormulaImpl
      de.uni_tuebingen.sfb.lichtenstein.formulas.ComposedFormula
          de.uni_tuebingen.sfb.lichtenstein.formulas.NaryJunctor

All Implemented Interfaces:

Formula, Visitable, Serializable

Direct Known Subclasses:

Conjunction, Disjunction

public abstract class NaryJunctor
extends ComposedFormula

A superclass for conjunction and disjunction, implementing common methods for binary junctors.

Author:

Hendrik Maryns

See Also:

Serialized Form

Method Summary

boolean	containsVariable(Variable var) Returns whether this formula contains the given variable.
Formula	getArgument(int index) Get the indexth argument.
int	getFirstIndexOf(Variable var) Get the first index at which the given variable occurs.
int	getNbArguments() Return the number of arguments.
int	getNbBoundVariables() Returns the number of bound variables in this formula.
int	getNbFreeVariables() Returns the number of free variables in this formula.
int	getNbSubformulas() Returns the number of subformulas of this formula.
int	getNbVariables() Returns the number of variables in this formula.
Set<Predicate>	getPredicates() Return all predicates that occur in this formula.
Formula	getSubformulaAt(int index) Returns the indexth subformula of this formula.
Variable	getVariableAt(int index) Get the indexth variable.
boolean	hasAsArgument(Formula form) Returns whether this n-ary junctor has the given formula as an argument.
int	hashCode() Returns a hash code value for the object.
boolean	isFreeVariable(Variable variable) Check whether the given variable is free in this formula.
String	toString() Returns a string representation of the object.

Methods inherited from class de.uni_tuebingen.sfb.lichtenstein.formulas.ComposedFormula

getAllSubformulas, getSymbol

Methods inherited from class de.uni_tuebingen.sfb.lichtenstein.formulas.FormulaImpl

accept, and, equals, exists, exists, forAll, forAll, getFreeVariables, getVariables, iff, implies, isClosed, not, or

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface de.uni_tuebingen.sfb.lichtenstein.formulas.Formula

getNormalForm

Method Detail

getNbArguments

public int getNbArguments()

Return the number of arguments.

Returns:

The number of arguments. This is the same as the number of subformulas.

| result == getNbSubformulas()

getArgument

public Formula getArgument(int index)
                    throws IndexOutOfBoundsException

Get the indexth argument.

Parameters:

index - The index of the argument wanted.

Returns:

The indexth argument.

| getSubformulaAt(index)

Throws:

IndexOutOfBoundsException

If the index is less than zero or more than the number of outgoing edges.

| index < 0 || index >=
         getNbArguments()

hasAsArgument

public boolean hasAsArgument(Formula form)

Returns whether this n-ary junctor has the given formula as an argument.

Parameters:

form - The formula which has to be checked.

Returns:

Whether the formula is an argument.

getNbSubformulas

public int getNbSubformulas()

Returns the number of subformulas of this formula.

Specified by:

getNbSubformulas in class ComposedFormula

getSubformulaAt

public Formula getSubformulaAt(int index)
                        throws IndexOutOfBoundsException

Returns the indexth subformula of this formula.

Specified by:

getSubformulaAt in class ComposedFormula

Parameters:

index - The index of the wanted subformula. Indices start from 0.

containsVariable

public boolean containsVariable(Variable var)

Returns whether this formula contains the given variable.

Parameters:

var - The variable to check.

Returns:

True if any of the arguments contains the given variable, false otherwise.

| if ( for one i in
         0..getNbArguments(): getArgument(i).containsVariable(var) )
| then result == true | else result == false

getFirstIndexOf

public int getFirstIndexOf(Variable var)

Get the first index at which the given variable occurs.

Parameters:

var - The variable of which the index is wanted.

getNbBoundVariables

public int getNbBoundVariables()

Returns the number of bound variables in this formula.

Returns:

The sum of the number of bound variables of the arguments.

| result ==
         Sum{getArgument(i).getNbBoundVariables()
|for each i in 0..getNbArguments()}

getNbFreeVariables

public int getNbFreeVariables()

Returns the number of free variables in this formula.

Returns:

The sum of the number of free variables of the arguments.

| result ==
         Sum{getArgument(i).getNbFreeVariables()
|for each i in 0..getNbArguments()}

getNbVariables

public int getNbVariables()

Returns the number of variables in this formula.

Returns:

The sum of the number of variables of the arguments.

| result == Sum{getArgument(i).getNbVariables()|for
         each i in 0..getNbArguments()}

getPredicates

public Set<Predicate> getPredicates()

Return all predicates that occur in this formula. TODO

getVariableAt

public Variable getVariableAt(int index)
                       throws IndexOutOfBoundsException

Get the indexth variable.

Parameters:

index - The index of the wanted variable

isFreeVariable

public boolean isFreeVariable(Variable variable)

Check whether the given variable is free in this formula.

Parameters:

variable - The variable to check.

Returns:

True if it is free in either argument.

| result == for one i in 0..getNbArguments():
         getArgument(i).isFreeVariable(variable)

hashCode

public int hashCode()

Returns a hash code value for the object.

This method should be overridden along with equals. For the reason, see Object.hashCode().

Specified by:

hashCode in class FormulaImpl

Returns:

The hash code is based on the hash codes of the arguments and of the characteristic symbol.

toString

public String toString()

Returns a string representation of the object.

formulas have a traditional string representation. No elimination of unnecessary parentheses is performed.

Specified by:

toString in class FormulaImpl

Returns:

The string representation of an n-ary junctor is the string representation of its arguments with an appropriate sign in between.

| for each i in 0..getNbArguments():
         result.contains(getArgument(i).toString())
| result.contains(getSymbol())