model

Class Rule

java.lang.Object

model.Rule

All Implemented Interfaces:

Cloneable, PCExpression

public class Rule
extends Object
implements PCExpression, Cloneable

This class represents the rules of the table of truth.

Author:

Alexandre Camus

Field Summary

Fields

Modifier and Type	Field and Description
private Clause	body
private SimpleSentence	head

Constructor Summary

Constructors

Constructor and Description
Rule(SimpleSentence head) Constructor of the class in case of a simple fact.
Rule(SimpleSentence head, Clause body) Constructor of the class in case of a backtracking rule.

Method Summary

Methods

Modifier and Type	Method and Description
Clause	getBody() Gets the body of the rule.
SimpleSentence	getHead() Gets the head of the rule.
Rule	replaceVariables(SubstitutionSet s) Replaces all the variables in the rule according to the specified bindings.
Rule	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 rule in the form of: "head :- body".

Methods inherited from class java.lang.Object

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

Field Detail

head

private SimpleSentence head

body

private Clause body

Constructor Detail

Rule

public Rule(SimpleSentence head)

Constructor of the class in case of a simple fact.

Parameters:

head - the fact that is declared true.

Rule

public Rule(SimpleSentence head,
    Clause body)

Constructor of the class in case of a backtracking rule.

Parameters:

head - the element that is defined by the rule.

body - the definition of the element.

Method Detail

getHead

public SimpleSentence getHead()

Gets the head of the rule. The head is either the fact that is declared as true or the element that is defined.

Returns:

a SimpleSentence object which is the head of the rule.

getBody

public Clause getBody()

Gets the body of the rule. The body is either null for a fact or a clause for a complete rule.

Returns:

a Clause object representing the body.

replaceVariables

public Rule replaceVariables(SubstitutionSet s)

Replaces all the variables in the rule 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 Rule object representing the bound rule.

See Also:

PCExpression.replaceVariables(model.SubstitutionSet)

standardizeVariablesApart

public Rule 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 Rule object representing the standardized rule.

See Also:

PCExpression.standardizeVariablesApart(java.util.Hashtable)

toString

public String toString()

Returns the rule in the form of: "head :- body".

Overrides:

toString in class Object

See Also:

Object.toString()