Issue 3171: Ambiguity of the containment relationship (ts-rtf)
Source: Fujitsu (Mr. Stephen McConnell, stephen.mcconnell(at)au.fujitsu.com)
Nature: Uncategorized Issue
Severity: 
Summary: The Task and Session Specification defines a "contains" relationship between
a Workspace and AbstractResources contained by the workspace. An
AbstractResources may be contained within many Workspaces and Workspaces are
themselves AbstractResources. However, the semantics of "contains" with
respect to strong or weak aggregation are ambiguous. Achievement of
consistent behaviour of lifecycle operations (remove, copy and move) across
implementations requires explicit distinction between strong containment as
opposed to weak containment. Strong containment is required in order to
associate a resource with 0 to 1 principal workspace. Under strong
containment, the removal of a containing workspace implies the removal of
strongly contained resources. Under weak containment the removal of a
containing workspace implies the removal of "contained_by" relationships
held by contained resources towards the workspace. Under strong containment,
it should be illegal for a resource to strongly contain a resource it is
already strongly contained by.

Resolution: 
Revised Text: 
Actions taken:
December 28, 1999: received issue
Discussion: 

End of Annotations:=====
From: "Stephen McConnell" <mcconnell@osm.net>
To: <issues@omg.org>
Cc: <ts-rtf@omg.org>, "Juergen Boldt" <juergen@omg.org>
Subject: Task Session 2.0 - 3 Issues
Date: Tue, 28 Dec 1999 13:56:52 +0100
Message-ID: <000001bf5133$033685b0$0a01a8c0@home.osm.net>
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Issues for submission to the Task and Session 2.0 RTF.
======================================================

	1. Management of event consumer association
	2. Access to resource creation and modification dates
	3. AbstractResource association count
	4. Ambiguity of the containment relationship


3. Ambiguity of the containment relationship
--------------------------------------------

The Task and Session Specification defines a "contains" relationship
between
a Workspace and AbstractResources contained by the workspace. An
AbstractResources may be contained within many Workspaces and
Workspaces are
themselves AbstractResources. However, the semantics of "contains"
with
respect to strong or weak aggregation are ambiguous. Achievement of
consistent behaviour of lifecycle operations (remove, copy and move)
across
implementations requires explicit distinction between strong
containment as
opposed to weak containment. Strong containment is required in order
to
associate a resource with 0 to 1 principal workspace. Under strong
containment, the removal of a containing workspace implies the removal
of
strongly contained resources. Under weak containment the removal of a
containing workspace implies the removal of "contained_by"
relationships
held by contained resources towards the workspace. Under strong
containment,
it should be illegal for a resource to strongly contain a resource it
is
already strongly contained by.

Stephen J. McConnell, OSM sarl
Business Components for Electronic Commerce
http://www.osm.net
mailto:mcconnell@osm.net