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 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.
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.
int	getFirstIndexOf(Variable var) Get the first index at which the given variable occurs.
int	getNbVariables() Returns the number of variables in this formula.
FirstOrderVariable	getPrecededVariable() Returns the preceded variable.
FirstOrderVariable	getPrecedingVariable() Returns the preceding variable.
Set<Predicate>	getPredicates() Return all predicates in this formula.
Variable	getVariableAt(int index) Get the indexth 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

getNbBoundVariables, getNbFreeVariables, getNormalForm, isFreeVariable

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

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

Methods inherited from class java.lang.Object

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

Postcondition:

The preceding variable is set to the given preceding variable.

| new.getPrecedingVariable() == preceding

Postcondition:

The preceded variable is set to the given preceded variable.

| new.getPrecededVariable() == preceded

Method Detail

getPrecedingVariable

public FirstOrderVariable getPrecedingVariable()

Returns the preceding variable.

Returns:

This is the first variable.

| result == getVariableAt(0)

getPrecededVariable

public FirstOrderVariable getPrecededVariable()

Returns the preceded variable.

Returns:

This is the second variable.

| result == getVariableAt(0)

getNbVariables

public int getNbVariables()

Returns the number of variables in this formula.

Returns:

Always 2.

| result == 2

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.

getVariableAt

public Variable getVariableAt(int index)
                       throws IndexOutOfBoundsException

Get the indexth variable.

Parameters:

index - The index of the wanted variable

containsVariable

public boolean containsVariable(Variable var)

Returns whether this formula contains the given variable. TODO

Parameters:

var - The variable to check.

getPredicates

public Set<Predicate> getPredicates()

Return all predicates in this formula.

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 equalities are equal if they compare the same variables.

| let otherEquals = (Dominance) other in |
         if ( otherEquals.getPrecedingVariable() != getPrecedingVariable() )
| then result == false | else if (
         otherEquals.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 de.uni_tuebingen.sfb.lichtenstein.exceptions.VisitorException

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

Specified by:

accept in interface Visitable

Overrides:

accept in class FormulaImpl

Parameters:

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

Throws:

VisitorException

A visitor can throw an exception.