model

Class SimpleSentence

java.lang.Object

model.SimpleSentence

All Implemented Interfaces:

Clause, PCExpression, Unifiable

public class SimpleSentence
extends Object
implements Unifiable, Clause

This class represents predicates. It implements Unifiable and Clause.

Author:

Alexandre Camus

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	isMatched
private List<Unifiable>	terms

Constructor Summary

Constructors

Modifier	Constructor and Description
	SimpleSentence(Constant predicateName, Unifiable... args) Constructor of the class.
private	SimpleSentence(List<Unifiable> args) Constructor of the class.

Method Summary

Methods

Modifier and Type	Method and Description
String	getName() Gets the name of the simple sentence.
SimpleSentenceSolutionNode	getSolver(RuleSet rules, SubstitutionSet parentSolution, AbstractSolutionNode parentNode) Creates a solver which is a node in the tree proof.
Unifiable	getTerm(int index) Gets the term at the specified index.
boolean	isMatched() Checks whether the name of the simple sentence matches so far a rule in the database.
int	length() Gets the length which is the number of parameters plus the name of the simple sentence.
SimpleSentence	replaceVariables(SubstitutionSet s) Replaces all the variables in the simple sentence according to the specified bindings.
SimpleSentence	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 simple sentence under the form of: "predicateName(parameter1, parameter2, ...)".
SubstitutionSet	unify(Unifiable expr, SubstitutionSet s) Unifies the simple sentence with the specified expr expression given the bindings s.

Methods inherited from class java.lang.Object

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

Field Detail

terms

private List<Unifiable> terms

isMatched

private boolean isMatched

Constructor Detail

SimpleSentence

public SimpleSentence(Constant predicateName,
              Unifiable... args)

Constructor of the class.

Parameters:

predicateName - the Constant representing the name of the predicate that is represented.

args - the parameters of this predicate in an array or as independent arguments.

SimpleSentence

private SimpleSentence(List<Unifiable> args)

Constructor of the class.

Parameters:

args - the name and the parameters of this predicate in an array or as independent arguments.

Method Detail

getSolver

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

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

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)

length

public int length()

Gets the length which is the number of parameters plus the name of the simple sentence. It counts the number of Constant and Variable objects used to represent the simple sentence.

Returns:

the number of parameters plus the name of the simple sentence.

getTerm

public Unifiable getTerm(int index)

Gets the term at the specified index. The index is the position of the parameter.

Parameters:

index - the position of the parameter.

Returns:

the parameter at the specified position.

getName

public String getName()

Gets the name of the simple sentence. It is the name of the predicate or the functor.

Specified by:

getName in interface Unifiable

Returns:

the name of the simple sentence.

See Also:

Unifiable.getName()

isMatched

public boolean isMatched()

Checks whether the name of the simple sentence matches so far a rule in the database.

Returns:

true if so far the simple sentence's name matches a rule.

replaceVariables

public SimpleSentence replaceVariables(SubstitutionSet s)

Replaces all the variables in the simple sentence 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 SimpleSentence object representing the bound simple sentence.

See Also:

PCExpression.replaceVariables(model.SubstitutionSet)

standardizeVariablesApart

public SimpleSentence 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 SimpleSentence object representing the standardized simple sentence.

See Also:

PCExpression.standardizeVariablesApart(java.util.Hashtable)

unify

public SubstitutionSet unify(Unifiable expr,
                    SubstitutionSet s)

Unifies the simple sentence with the specified expr expression given the bindings s. This tries to get or add bindings in order to make logically equivalent the simple sentence and the specified expression.

This method is recursive over all Unifiable implementations.

Specified by:

unify in interface Unifiable

Parameters:

expr - an expression to unify with the simple sentence.

s - the SubstitutionSet object representing the bindings so far and/or the constraints applied.

Returns:

a SubstitutionSet object that contains all the bindings needed to unify the simple sentence to the specified expression.

See Also:

Unifiable.unify(Unifiable, SubstitutionSet)

toString

public String toString()

Returns the simple sentence under the form of: "predicateName(parameter1, parameter2, ...)".

Overrides:

toString in class Object

See Also:

Object.toString()