org.jutil.relation
Class ReferenceSet

java.lang.Object
  |
  +--org.jutil.relation.Relation
        |
        +--org.jutil.relation.ReferenceSet

public class ReferenceSet

extends Relation

A class of Relation components for implementing a binding in which the object of the Reference has a relation with N other objects. This component behaves as a set.

In UML this class is used for implementing multiplicity n:

In Java, you get the following situation.

Note that the question mark is represented by a Relation object since we don't know its multiplicity. The double binding between the ReferenceSet object and A is made by passing this to the constructor of ReferenceSet.

This is actually a lightweight version of the APSet class. of the Beedra framework of Jan Dockx.

This class is typically using in the following way.

public class A {
  public A() {
    _b= new ReferenceSet(this);
  }
  public List getBs() {
    return _b.getOtherEnds();
  }
  // public Set getBs() {
  //   return new TreeSet(_b.getOtherEnds());
  // }
  public void addB(B b) {
    _b.add(b.getALink());
  }
  public void removeB(B b) {
    _b.remove(b.getALink());
  }
  private ReferenceSet _b;
}
 

The other class must have a method getALink(), which returns a Relation object that represents the other side of the bi-directional binding. In case the two classes are not in the same package that means that getALink() must be public there, but that is also the case when not working with these components. Note that if the binding should not be mutable from class A the addB() may be removed. Similarly, getBLink() may be removed if the binding is not mutable from class B.

If getBs() must return a Set, you should add the result of _b.getOtherEnds() to a new Set (e.g. TreeSet). The general method getOtherEnds() must return a List because in some bindings the order may be important.

Class Specifications

public invariant contains(null) == false; public invariant getObject() != null; public invariant ( \forall Relation e; contains(e); e.contains(this));

Field Summary
static java.lang.String	CVS_REVISION

 

Constructor Summary

ReferenceSet(java.lang.Object object)           Initialize an empty ReferenceSet for the given object.

 

Method Summary
void	add(Relation element)           Add the given Relation to this ReferenceSet.
boolean	contains(Relation element)           Check whether or not the given element is connected to this ReferenceSet.
java.util.List	getOtherEnds()           Return a set containing the objects at the n side of the 1-n binding.
java.util.List	getOtherRelations()           Return a set containing the Relations at the other side of this binding.
protected  boolean	isValidElement(Relation relation)
protected  void	register(Relation element)           Add the given Relation to this ReferenceSet
boolean	registered(java.util.List oldConnections, Relation registered)
void	remove(Relation other)           Remove the given Relation from this ReferenceSet.
int	size()           Return the size of the ReferenceSet
protected  void	unregister(Relation element)           Remove the given Relation from this ReferenceSet
boolean	unregistered(java.util.List oldConnections, Relation unregistered)

 

Methods inherited from class org.jutil.relation.Relation

equals, getObject

 

Methods inherited from class java.lang.Object

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

 

Field Detail

CVS_REVISION

public static final java.lang.String CVS_REVISION

ReferenceSet

public ReferenceSet(java.lang.Object object)

Initialize an empty ReferenceSet for the given object.

Parameters:

object - The object on this side of the binding

Specifications:

public behavior
requires object != null;
ensures getObject() == object;
ensures ( \forall Relation r; ; !contains(r));

remove

public void remove(Relation other)

Remove the given Relation from this ReferenceSet.

Parameters:

element - The Relation to be removed.

Specifications:

public behavior
requires other != null;
ensures unregistered(\old(getOtherRelations()),other);
ensures other.unregistered(\old(other.getOtherRelations()),this);

add

public void add(Relation element)

Add the given Relation to this ReferenceSet.

Parameters:

element - The Relation to be added.

Specifications:

public behavior
requires element != null;
ensures registered(\old(getOtherRelations()),element);
ensures element.registered(\old(element.getOtherRelations()),this);

getOtherEnds

public java.util.List getOtherEnds()

Return a set containing the objects at the n side of the 1-n binding.

Specifications:

     also

public behavior
ensures ( \forall Object o; ; \result .contains(o) <==> ( \exists Relation r; contains(r); r.getObject().equals(o)));
ensures \result != null;

Specifications inherited from overridden method in class Relation:

public behavior
ensures \result != null;
ensures \result .size() == getOtherRelations().size();
ensures ( \forall Object o; \result .contains(o); ( \exists Relation r; getOtherRelations().contains(r); r.getObject() == o));

getOtherRelations

public java.util.List getOtherRelations()

Return a set containing the Relations at the other side of this binding.

Specifications:

     also

public behavior
ensures ( \forall Relation s; ; contains(s) <==> \result .contains(s));
ensures \result != null;

Specifications inherited from overridden method in class Relation:

public behavior
ensures \result != null;
ensures ( \forall Object o; \result .contains(o); o instanceof Relation);
ensures !\result .contains(null);

unregister

protected void unregister(Relation element)

Remove the given Relation from this ReferenceSet

Parameters:

element - The element to be removed.

Specifications:

     also

protected behavior
requires element != null;
ensures !contains(element);

Specifications inherited from overridden method in class Relation:

protected behavior
requires contains(other);
ensures unregistered(\old(getOtherRelations()),other);

register

protected void register(Relation element)

Add the given Relation to this ReferenceSet

Parameters:

element - The element to be added.

Specifications:

     also

protected behavior
requires element != null;

Specifications inherited from overridden method in class Relation:

protected behavior
requires isValidElement(other);
ensures registered(\old(getOtherRelations()),other);

registered

public boolean registered(java.util.List oldConnections,
                          Relation registered)

Specifications:

     also

public behavior
ensures \result == (contains(registered))&&( \forall Relation r; r != registered; oldConnections.contains(r) == contains(r));

Specifications inherited from overridden method in class Relation:

public behavior
requires oldConnections != null;
requires !oldConnections.contains(null);
requires ( \forall Object o; oldConnections.contains(o); o instanceof Relation);
ensures !contains(registered) ==> \result == false;
ensures !( \forall Relation r; r != registered; oldConnections.contains(r) == contains(r)) ==> \result == false;

unregistered

public boolean unregistered(java.util.List oldConnections,
                            Relation unregistered)

Specifications:

     also

public behavior
ensures \result == (oldConnections.contains(unregistered))&&( \forall Object o; oldConnections.contains(o); o instanceof Relation)&&(!contains(unregistered))&&( \forall Relation r; r != unregistered; oldConnections.contains(r) == contains(r));

Specifications inherited from overridden method in class Relation:

public behavior
requires oldConnections != null;
requires !oldConnections.contains(null);
requires ( \forall Object o; oldConnections.contains(o); o instanceof Relation);
ensures contains(unregistered) ==> \result == false;
ensures !oldConnections.contains(unregistered) ==> \result == false;
ensures !( \forall Relation r; r != unregistered; oldConnections.contains(r) == contains(r)) ==> \result == false;

isValidElement

protected boolean isValidElement(Relation relation)

Specifications:

     also

public behavior
ensures \result == (relation != null);

Specifications inherited from overridden method in class Relation:

public behavior
ensures \result == true|\result == false;

size

public int size()

Return the size of the ReferenceSet

Specifications:

public behavior
ensures \result == getOtherRelations().size();

contains

public boolean contains(Relation element)

Check whether or not the given element is connected to this ReferenceSet.

Overrides:

contains in class Relation

Parameters:

element - The element of which one wants to know if it is in this ReferenceSet.

Specifications inherited from overridden method in class Relation:

public behavior
ensures \result == getOtherRelations().contains(relation);