de.uni_tuebingen.sfb.lichtenstein.formulas
Class Precedence

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

All Implemented Interfaces:

Formula, Visitable, Serializable

public final class Precedence
extends AtomicFormula

A class representing the atomic formula which says one node precedes another.

Author:

Hendrik Maryns

See Also:

Serialized Form

Constructor Summary

Precedence(FirstOrderVariable preceder, FirstOrderVariable preceded)
Initialize a new precedence, taking two variables as arguments.

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.
FirstOrderVariable	getPrecededVariable() Returns the preceded variable.
FirstOrderVariable	getPrecedingVariable() Returns the preceding 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

Precedence

public Precedence(FirstOrderVariable preceder,
                  FirstOrderVariable preceded)

Initialize a new precedence, taking two variables as arguments.

Parameters:

preceder - The variable which is preceding the other variable.

preceded - The variable which is preceded by the other variable.

Precondition:

Both variables must be effective. | preceding != null && preceded != null

Postconditions:

The preceding variable is set to the given preceding variable. | new.getPrecedingVariable() == preceding

The preceded variable is set to the given preceded variable. | new.getPrecededVariable() == preceded

Method Detail

getPrecedingVariable

public FirstOrderVariable getPrecedingVariable()

Returns the preceding variable.

Returns:

The first variable.

getPrecededVariable

public FirstOrderVariable getPrecededVariable()

Returns the preceded 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(getPrecedingVariable()) && | result.contains(getPrecededVariable())

containsVariable

public boolean containsVariable(Variable var)

Returns whether this formula contains the given variable. TODO

Parameters:

var - The variable to check.

computePredicates

protected Set<Predicate> computePredicates()

Return all predicates in this formula.

Specified by:

computePredicates in class FormulaImpl

Returns:

A precedence cannot contain predicates. | result.isEmpty()

equals

public boolean equals(Object other)

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

Overrides:

equals in class FormulaImpl

Returns:

Two precedences are equal if they compare the same variables. | let otherPrec = (Precedence) other in | if ( otherPrec.getPrecedingVariable() != getPrecedingVariable() ) | then result == false | else if ( otherPrec.getPrecededVariable() != getPrecededVariable() ) | 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 == getPrecedingVariable().hashCode() + "≺≺".hashCode() + getPrecededVariable().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 sign for precedence: ≺≺ in between them.
result == getPrecedingVariable().toString() + " ≺≺ " + getPrecededVariable().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.