Issue 1450:  BocaFeature should redefine the defines relationship (boca-rtf)
Source:  (, )
Nature:  Revision
Severity: 
Summary: Summary:  BocaFeature should redefine the defines relationship that it inherits from Feature by 
 adding a constraint stating that the relationship can only be populated by an instance of 
 BocaFeatureOwner.   
 

Resolution: 
Revised Text: 
Actions taken:
June 3, 1998: received issue
June 23, 1998: closed issue
Discussion: 

End of Annotations:=====
*ISSUE 22*

Section 2.2.4 (BOCA Meta-Model in CDL)

identifiable BocaType:BocaFeatureOwner,CorbaInterface{
        attribute boolean has_identity=FALSE;
        attribute boolean is_abstract=FALSE;
        attribute boolean is_singleton = FALSE;
        [constraint=(is_leaf?!is_abstract:TRUE)] attribute boolean
is_leaf=FALSE;
        attribute ChangeableKind changeable=IS_CHANGEABLE;
        [constraint=pass_by_value?!has_identity:TRUE] attribute
boolean pass_by_value=FALSE;
        attribute string technology_mapping=null;
        [MANAGER, is_read_only] relationship base_type Uses
BocaType=BaseComponent;
        [MANAGER, is_read_only] attribute string keyword="type";
}; /* BoaType */

[is_abstract] identifiable BocaFeature: AbstractFeature{
        attribute boolean is_read_only=FALSE;
        attribute ScopeKind target_scope=INSTANCES;
        attribute VisibilityKind visibility=PUBLIC;
        attribute EventKind events=TRIGGERED_EVENTS;
        attribute string event_subject;
        attribute boolean is_locked=FALSE;
        [MANAGER,is_read_only] attribute string keyword;
        attribute boolean export=FALSE;
        // attribute BocaFeature redefines;
        relationship redefines References BocaFeature inverse
redefined_by;
        relationship redefined_by References BocaFeature inverse
redefines;
}; /* Feature */

The corresponding UML diagram (section 2.2.2.1) shows a relationship
between BocaFeatureOwner and 
BocaFeature, which is a redefinition of the relationship between
FeatureOwner and Feature.  As discussed 
in issues 18 and 19, the redefinition should be handled by adding
constraints rather than narrowing the 
types in the relationship declaration itself.

Recommendation: BocaFeature should redefine the defines relationship
that it inherits from Feature by 
adding a constraint stating that the relationship can only be
populated by an instance of 
BocaFeatureOwner.  

On the other hand, it is not clear whether BocaFeatureOwner should
redefine the has_features relationship 
that it inherits from FeatureOwner by adding a constraint stating that
the relationship can only be populated 
by BocaFeature instances, because it might be necessary for a
BocaFeatureOwner to be composed, at 
least partially, by instances of Feature that are not instances of
BocaFeature.