org.lacibus.storeaccess

Class JoinConstraint

java.lang.Object

org.lacibus.storeaccess.JoinConstraint

public class JoinConstraint
extends java.lang.Object

An assertion that quantities are related in a certain way.

A constraint has a subject, a verb, and an object, each of which can either be unknown or given. The unknown quantities are termed "unknowns". Each unknown has a name, and can appear in multiple constraints.

A triple satisfies a constraint if it satisfies the following conditions.

• If the subject of the constraint is a given then the subject of the triple is that given
• If the verb of the constraint is a given then the verb of the triple is that given
• If the object of the constraint is a given then the object of the triple is that given.
• If the subject and verb of the constraint are the same unknown, then the subject and verb of the triple are the same item.
If the subject and object of the constraint are the same unknown, then the object of the triple is an item datum whose value is the same as the subject of the triple.
• If the verb and object of the constraint are the same unknown, then the object of the triple is an item datum whose value is the same as the verb of the triple.

If a triple satisfies a constraint then it defines an assignment of values to the variables in the constraint.

• If the subject of the constraint is an unknown then the value assigned to it is the subject of the triple.
• If the verb of the constraint is an unknown then the value assigned to it is the verb of the triple.
• If the object of the constraint is an unknown then the value assigned to it is the object of the triple.

Constructor Summary

Constructors

Constructor and Description
JoinConstraint(Quantum subject, Quantum verb, Quantum object) Create a join constraint

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj)
Quantum	getObject()
Quantum	getSubject()
Quantum	getVerb()
int	hashCode()
java.lang.String	toString()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

JoinConstraint

public JoinConstraint(Quantum subject,
                      Quantum verb,
                      Quantum object)

Create a join constraint

Parameters:

subject - the subject of the constraint

verb - the verb of the constraint

object - the object of the constraint

Method Detail

getSubject

public Quantum getSubject()

Returns:

the subject of the constraint

getVerb

public Quantum getVerb()

Returns:

the verb of the constraint

getObject

public Quantum getObject()

Returns:

the object of the constraint

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object