de.uni_tuebingen.sfb.lichtenstein.formulas
Class Dominance

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

All Implemented Interfaces:

Formula, Visitable, Serializable

public class Dominance
extends AtomicFormula

A class representing the atomic formula which says one node dominates another. This is the transitive, reflexive closure of immediate dominance.

Author:

Hendrik Maryns

See Also:

Serialized Form

Constructor Summary

Dominance(FirstOrderVariable dominator, FirstOrderVariable dominated)
Initialize a new dominance, 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.
FirstOrderVariable	getDominatedVariable() Returns the dominated variable.
FirstOrderVariable	getDominatingVariable() Returns the dominating variable.
int	getFirstIndexOf(Variable var) Get the first index at which the given variable occurs.
int	getNbVariables() Returns the number of variables in this formula.
Set<Predicate>	getPredicates() Return all predicates in this formula.
Variable	getVariableAt(int index) Get the indexth variable (free or bound).
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

Dominance

public Dominance(FirstOrderVariable dominator,
                 FirstOrderVariable dominated)

Initialize a new dominance, taking two variables as arguments.

Parameters:

dominator - The variable which is dominating the other variable.

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

Precondition:

Both variables must be effective.

| dominator != null && dominated != null

Postcondition:

The dominator variable is set to the given dominator variable.

| new.getDominatingVariable() == dominator

Postcondition:

The dominated variable is set to the given dominated variable.

| new.getDominatedVariable() == dominated

Method Detail

getDominatingVariable

public FirstOrderVariable getDominatingVariable()

Returns the dominating variable.

Returns:

This is the first variable.

| result == getVariableAt(0)

getDominatedVariable

public FirstOrderVariable getDominatedVariable()

Returns the dominated 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 (free or bound).

Parameters:

index - The index of the wanted variable

containsVariable

public boolean containsVariable(Variable var)

Returns whether this formula contains the given variable.

Parameters:

var - The variable to check.

getPredicates

public Set<Predicate> getPredicates()

Return all predicates in this formula.

Returns:

A dominance 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.getDominatingVariable() != getDominatingVariable() )
| then result == false | if (
         otherEquals.getDominatedVariable() != getDominatedVariable() )
| then result == false

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 ==
         getDominatingVariable().hashCode() + "⊲*".hashCode() + getDominatedVariable().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 dominance: ⊲* in between them.

| result == getDominatingVariable().toString() + "⊲*" + getDominatedVariable().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.