de.uni_tuebingen.sfb.lichtenstein.formulas
Class Subset

java.lang.Object
  de.uni_tuebingen.sfb.lichtenstein.formulas.FormulaImpl
      de.uni_tuebingen.sfb.lichtenstein.formulas.AtomicFormula
          de.uni_tuebingen.sfb.lichtenstein.formulas.Subset

All Implemented Interfaces:

Formula, Visitable, Serializable

public class Subset
extends AtomicFormula

A class for representing the atomic formula which says a variable is a subset of another variable

Author:

Hendrik Maryns

See Also:

Serialized Form

Constructor Summary

Subset(SetDenotator subSet, SetDenotator superSet)
Initialize a new subset formula, involving the variable which is a subset and the variable which is a superset.

Method Summary

void	accept(FormulaVisitor visitor) Accept a formula visitor.
protected Set<Predicate>	computePredicates() Return all predicates in this formula.
protected Set<Variable>	computeVariables() Simply return the two variables.
boolean	containsVariable(Variable var) Returns whether this formula contains the given variable.
boolean	equals(Object other) Indicates whether some other object is “equal to” this one.
SetDenotator	getSubsetVariable() Returns the subset variable.
SetDenotator	getSupersetVariable() Returns the superset variable.
int	hashCode() Returns a hash code value for the object.
String	toString() Returns a string representation of the object.

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

getNormalForm, isFree

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

and, exists, exists, forAll, forAll, getFreeVariables, getPredicates, getVariables, iff, implies, isClosed, not, or

Methods inherited from class java.lang.Object

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

Constructor Detail

Subset

public Subset(SetDenotator subSet,
              SetDenotator superSet)

Initialize a new subset formula, involving the variable which is a subset and the variable which is a superset.

Parameters:

subSet - The variable which is a subset.

superSet - The variable which is a superset.

Precondition:

Both variables must be effective. | subSet != null && superSet != null

Postconditions:

The subset variable is set to the given subset variable. | new.getSubsetVariable() == subSet

The superset variable is set to the given superset variable. | new.getSupersetVariable() == superSet

Method Detail

getSubsetVariable

public SetDenotator getSubsetVariable()

Returns the subset variable.

Returns:

The first variable.

getSupersetVariable

public SetDenotator getSupersetVariable()

Returns the superset variable.

Returns:

The second variable.

computeVariables

protected Set<Variable> computeVariables()

Simply return the two variables.

Specified by:

computeVariables in class FormulaImpl

Returns:

The two variables in the right order. | result.size() == 2 && | result.contains(getSubsetVariable()) && | result.contains(getSupersetVariable())

containsVariable

public boolean containsVariable(Variable var)

Returns whether this formula contains the given variable.

Parameters:

var - The variable to check.

Returns:

A subset formula does not contain any first order variables. | result == false

computePredicates

protected Set<Predicate> computePredicates()

Return all predicates in this formula.

Specified by:

computePredicates in class FormulaImpl

Returns:

Both variables can be a predicate. | if ( getSubsetVariable() instanceof Predicate ) | then result.contains(getSubsetVariable()) | if ( getSupersetVariable() instanceof Predicate ) | then result.contains(getSupersetVariable())

equals

public boolean equals(Object other)

Indicates whether some other object is “equal to” this one.

Overrides:

equals in class FormulaImpl

Returns:

Two subset atomic formulas are equal if they compare the same variables. | let otherSubset = (Subset) other in | if ( otherSubset.getSubsetVariable() == getSubsetVariable() ) | then result == false | else if ( otherSubset.getSupersetVariable() == getSupersetVariable() ) | then result == false | else result == true

hashCode

public int hashCode()

Returns a hash code value for the object.

Specified by:

hashCode in class FormulaImpl

Returns:

The hash code is based on the hash codes of the variables and of the characteristic symbol. | result == getSubsetVariable().hashCode() + "⊂".hashCode() + getSupersetVariable().hashCode()

toString

public String toString()

Returns a string representation of the object.

Specified by:

toString in class FormulaImpl

Returns:

The string representations of the variables are given, with the unicode symbol SUBSET OF: ⊂ in between them. | result == getSubsetVariable().toString() + "⊂" + getSupersetVariable().toString()

accept

public void accept(FormulaVisitor visitor)
            throws VisitorException

Accept a formula visitor. The iteration is done by the visitor, not by the composed formulas.

Parameters:

visitor - The visitor that is to be accepted to do its work.

Throws:

VisitorException - [CAN] A visitor can throw an exception.