Issue 1082:  Generated operations returning attributes/references should not raise Cons (mof-rtf)
Source:  (, )
Nature:  Uncategorized Issue
Severity: 
Summary: Summary: The generated IDL for the MOF includes ConstraintError in
 the raises clause of operations generated via the Attribute
 Template and Reference Template, although these templates do
 not include spcification of that exception (identified in a
 separate issue).  When that specification is updated, it
 should specify that the generated "read" operations do not
 raise this exception.  The current IDL has ConstraintError
 in the raises clause of the following operations, which do
 not change the state of the model:
 

Resolution: 
Revised Text: 
Actions taken:
March 18, 1998: received issue
July 23, 1999: deferred, pending issue 2181
Discussion: 
Response: The situation is more complex than it seems. What should we do if we discover
that the current value of an Attribute or Reference violates the applicable Constraints? Do
we raise the ConstraintError exception, or just return the value and not warn the user thatthe value is violating the model's constraints?
Deferred pending specification of Constraint verification. (#1085).
Implementation: This issue is mostly superceded by the overhaul of the exceptions in
which ConstraintError is rolled into MofError; see “Issue 1085:
Consider a better approach to generated exceptions (mof-rtf)”.
Implementation: However, we should not rule out constraint errors occuring in At-tribute
/ Reference read operations. In particular, when the At-tribute
or referenced Association is derived. This is discussed in
Section 4.11.5, “Access operations should avoid raising Constraint
exceptions,” on page 4-23. 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:  Generated operations returning
attributes/references sh
	ould not raise ConstraintError
Date: Wed, 18 Mar 1998 13:29:34 -0500

The generated IDL for the MOF includes ConstraintError in
the raises clause of operations generated via the Attribute
Template and Reference Template, although these templates do
not include spcification of that exception (identified in a
separate issue).  When that specification is updated, it
should specify that the generated "read" operations do not
raise this exception.  The current IDL has ConstraintError
in the raises clause of the following operations, which do
not change the state of the model:

   StructuralFeature::multiplicity()
   Operation::exceptions() 
   TypeAlias::multiplicity()
   AssociationEnd::multiplicity()
   Parameter::multiplicity()

The IDL should be revised to remove the ConstraintError
exception from the raises clauses of these operations.

If the MOF cannot insure that these operations are query 
operations, then they may not be reliably used to implement
constraints which enforce invariants.  For distributed objects,
that will make constraint evaluation difficult or impossible.