Issue 1077:  Description of meta-model as a single package is incorrect (mof-rtf)
Source:  (, )
Nature:  Uncategorized Issue
Severity: 
Summary: Summary: Section 6.3, Rules of ModelElement Containment, states that
 a "metamodel is defined by a Package object...".  In The
 section on Repository naming "Element, Model, and Repository
 Naming" the text states: "A metamodel name is the name of
 its top-level Package..." In other places I believe the
 document also either states or implies that a Model is
 defined by a single package (and its contents).
 
 

Resolution: nothing to do...close issue
Revised Text: 
Actions taken:
March 18, 1998: received issue
May 8, 2000: closed issue
Discussion: 
Response: The facts of the matter are:
1. Containment. Every MOF object (apart from the root of the MOF repository) is con-tained
within some other MOF object in a strict tree structure. This ensures that related
"chunks" of the MOF can be copied, moved, and deleted by copying, moving or deleting the
root of that sub-tree.
2. Relationship between metamodel and Package. A metamodel is represented by a Pack-age.
The concepts and relationships of that meta-model are represented by the various
ModelElements contained within that Package or reachable from that Package by inherit-ance/
import . Conversely, every Package is a representation of some metamodel.
3. Package naming. Section 6.7.1 defines a recommended naming convention to ensure
global uniqueness of metamodel/Package names. However, some large meta-models are
represented by a number of Packages, either by the nesting of Packages or by cross-linking
between Packages, and it might not be clear which of these Packagesshould be the "entry-point"
to the metamodel.
Section 6.3 should be reworded to make points 1 and 2 clearer. When Packages are nested,
the outermost Package should be identified as the "entry point" to the meta-model. If there
is a set of inter-linked Packages (without an outer containing Package), this means there
is a corresponding set of inter-linked metamodels, each of which is entitled to its own glo-bal
name designating a separate entrypoint. This should be added to Section 6.7.1.
Proposed resolutions:
1. Adopt Package clustering / consolidation proposal (see #Issue2176). This provides a
new mechanism for assembling free-standing Packages.
2. In sections 6.3 and 6.7.1, document that a meta-model is denoted by a closure of a
single Package as described above.
Implementation: 1) Nothing to do here. Done. [SC]
End of Annotations:=====
Return-Path: <GK.Khalsa@unisys.com>
From: "Khalsa, GK" <GK.Khalsa@unisys.com>
To: issues@omg.org, mof-rtf@omg.org
Subject: MOF-RTF: description of meta-model as a single package is
incorre
	ct
Date: Wed, 18 Mar 1998 10:08:31 -0800

Section 6.3, Rules of ModelElement Containment, states that
a "metamodel is defined by a Package object...".  In The
section on Repository naming "Element, Model, and Repository
Naming" the text states: "A metamodel name is the name of
its top-level Package..." In other places I believe the
document also either states or implies that a Model is
defined by a single package (and its contents).

However, a metamodel may comprise multiple top-level
packages, as was the case with the UML metamodel.  Although
"model" and "meta-model" are only concepts, not modeling
constructs, they are central to the purpose and use of the
Mof.  Suggest changing document to avoid defining models and
meta-models as a single package, and perhaps to refine the
definition of each.