model

Class Equal

java.lang.Object

model.Equal

All Implemented Interfaces:

Clause, PCExpression

public class Equal
extends Object
implements Clause

This class represents equal clauses. It is a binary operator. It extends Clause.

Equal clauses are useless as the use of constants or identical variables replaces it. The purpose of this class is to represent negative equalities.

Author:

Alexandre Camus

Field Summary

Fields

Modifier and Type	Field and Description
(package private) Unifiable	operand1
(package private) Unifiable	operand2

Constructor Summary

Constructors

Constructor and Description
Equal(Unifiable operand1, Unifiable operand2) Constructor of the class

Method Summary

Methods

Modifier and Type	Method and Description
Unifiable	getOperand1() Gets the left operand of the equal sentence.
Unifiable	getOperand2() Gets the right operand of the equal sentence.
EqualSolutionNode	getSolver(RuleSet rules, SubstitutionSet parentSolution, AbstractSolutionNode parentNode) Creates a solver which is a node in the tree proof.
Equal	replaceVariables(SubstitutionSet s) Replaces all the variables in the equal clause according to the specified bindings.
Equal	standardizeVariablesApart(Hashtable<Variable,Variable> newVars) Standardizes the variables in order to be sure that there won't be any variable clashes.
String	toString() Returns the equal clause under the form of: "operand1 == operand2".

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

operand1

Unifiable operand1

operand2

Unifiable operand2

Constructor Detail

Equal

public Equal(Unifiable operand1,
     Unifiable operand2)

Constructor of the class

Parameters:

operand1 - the left operand of the equal sentence.

operand2 - the right operand of the equal sentence.

Method Detail

getOperand1

public Unifiable getOperand1()

Gets the left operand of the equal sentence.

Returns:

the left operand of the equal sentence.

getOperand2

public Unifiable getOperand2()

Gets the right operand of the equal sentence.

Returns:

the right operand of the equal sentence.

getSolver

public EqualSolutionNode getSolver(RuleSet rules,
                          SubstitutionSet parentSolution,
                          AbstractSolutionNode parentNode)

Creates a solver which is a node in the tree proof. This is the version for the equality.

This function is recursive over all objects that can be proved and creates the tree of proof for a clause.

Specified by:

getSolver in interface Clause

Parameters:

rules - the RuleSet object containing the rules of knowledge.

parentSolution - the solution known so far at the parent node.

parentNode - the parent node in the tree.

Returns:

the node of the tree of proof.

See Also:

Clause.getSolver(RuleSet, SubstitutionSet, AbstractSolutionNode)

replaceVariables

public Equal replaceVariables(SubstitutionSet s)

Replaces all the variables in the equal clause according to the specified bindings.

This method is recursive over all PCExpression implementations.

Specified by:

replaceVariables in interface PCExpression

Parameters:

s - the SubstitutionSet that contains the bindings of the variables so far.

Returns:

a Equal object representing the bound equal clause.

See Also:

PCExpression.replaceVariables(model.SubstitutionSet)

standardizeVariablesApart

public Equal standardizeVariablesApart(Hashtable<Variable,Variable> newVars)

Standardizes the variables in order to be sure that there won't be any variable clashes.

This method is recursive over all PCExpression implementations.

Specified by:

standardizeVariablesApart in interface PCExpression

Parameters:

newVars - is a parameter to save over the recursion all the variable replacements done so far.

Returns:

a Equal object representing the standardized equal clause.

See Also:

PCExpression.standardizeVariablesApart(java.util.Hashtable)

toString

public String toString()

Returns the equal clause under the form of: "operand1 == operand2".

Overrides:

toString in class Object

See Also:

Object.toString()