Hi folks,
The link for this issue in the SCA Policy
TC JIRA: http://www.osoa.org/jira/browse/POLICY-31
Regards,
Kaanu Joshi
From: David Booz
[mailto:booz@us.ibm.com]
Sent: Saturday, October 20, 2007
12:59 AM
To:
sca-policy@lists.oasis-open.org
Subject: [sca-policy] NEW ISSUE:
Is it possible to use only a piece of a more general policySet?
TARGET:
SCA Policy Framework
DESCRIPTION:
Are policies from a policySet in effect just because the containing policySet
is attached to the SCA construct?
1. There could be "standalone" policies in the policySet or there
could be defaults from the contained intentMaps.
2. Spec seems to be clear that standalone policies would be in effect, but the
spec is not clear that defaults from intentMaps should also be in effect.
It is not clear whether policies in a policySet that are not referenced by the
list of required intents are always applicable.
What exactly is the effect of having a list of required intents? Are the
intentMaps in the policySet that are not referenced by the list of required
intents ignored? Or is the semantic that all parts of the attached policySet
always apply, and the list of required intents is used only for overriding the
defaults in the contained intentMaps?
How to handle standalone policies should also be addressed while addressing
this issue.
In particular, consider the following two cases and the questions they raise:
A> There are no required intents declared, and an attached policySet
contains some standalone policies and some intentMaps
Questions:
- Do standalone policies in the policySet apply?
- Should all the intentMaps contained in the policySet be considered? Should
the policies for the default qualifier in each considered intentMap be applied?
B> There are required intents declared, and an attached policySet includes
intentMaps for some of the required intents, intentMaps for some other intents,
and also some standalone policies.
- Do standalone policies in the policySet apply?
- Should intentMaps pertaining to intents that are not listed as required be
considered? For each such intentMap, should the policies for the default
qualifier be applied?
PROPOSAL:
We explored a few solutions:
1. Restrict Policy Sets to have only a single intent map [AM: We need
multiple intent maps to represent Policy Sets for, for example BP 1.0
that covers multiple policy areas.]
2. Allow the user of a Policy Set to specify which of the multiple *intent
maps* should be used.
3. Add an attribute to the Policy Set that says, use the individual intent map
that is required or use all the intents maps in the Policy Set.
4. In cases where there are multiple intent maps in a Policy Set each
intent map must have a "Null" option that could be chosen to
effectively
remove that intent map from participation. This requires no change to
the spec.
PROVENANCE: SCA-249
Dave Booz
STSM, SCA and WebSphere Architecture
Co-Chair OASIS SCA-Policy TC
"Distributed objects first, then world hunger"
Poughkeepsie,
NY (845)-435-6093 or 8-295-6093
e-mail:booz@us.ibm.com
http://washome.austin.ibm.com/xwiki/bin/view/SCA2Team/WebHome