Fwd: [soa-rm-ra] Review of Section 3.1.4 Policies and Contracts

-----Original Message-----
From: mpoulin@usa.com
To: danny_thornton2@yahoo.com
Sent: Tue, Jan 11, 2011 9:40 am
Subject: Re: [soa-rm-ra] Review of Section 3.1.4 Policies and Contracts

I also dislike this definition of contract as specified below:

Contract
A contract represents an agreement by two or more participants to constrain 
their behavior and/or state.

Prefer the shorter definition for Contract.

I think that 'constraint ... behavior and/or state' does not reflect the semantics of the Service Contract.

Particularly, contract defines:

1) what exactly a consumer may use from the spectrum of service characteristics, qualities and policies announced in the Service Description document, AND

2) what additional policies the service provider agrees to apply to the service interaction

Thus, Service Contract DOES NOT constrain behavior of service provider (one party of the agreement) but instead it constraints service behavior and this constraint happens ONLY if the consumer adds its policies. Also, the Service Contract DOES NOT constrain behavior of consumer (another party of the agreement) but instead it constraints 'legitimate' choice of what it can do with the service. This, however, does not constraint 'illegitimate' behavior of the consumer with regard to the service - consumer always may send request to the service interface, which is not listed in the Service Contract. In this case, the service has rights to deny the request.

I do not understand how an agreement regarding service can constraint a state of consumer, or service, or service provider.

I would agree with something like this:

1071 Contract

1072 A contract represents an agreement made by two or more participants

1073 (the contracting parties) on a set of promises (or contractual terms)

1074 together with a set of constraints that govern participants behavior in

1075 fulfilling those promises

(or 'with regard to those promises')

In other words, contract constraints participants' behavior only in relation with the promises agreed in the contract.

The model I see is: Service Description=promises -> Service Contract=agreement on sub-set of promises (or all promises) + consumer's policies=constraints that govern participants behavior in fulfilling promises

- Michael

-----Original Message-----
From: Danny Thornton <danny_thornton2@yahoo.com>
To: soa-rm-ra@lists.oasis-open.org
Sent: Tue, Jan 11, 2011 5:52 am
Subject: [soa-rm-ra] Review of Section 3.1.4 Policies and Contracts

Editors' Draft 2010-12-21 (Main Changes tracked).pdf

Line 913
A commitment is a type of constraint, redundant to add "commitment and/or".

Line 914
"and stakeholder alone" is redundant.

Line 917
A constraint may be measured and enforced by SOA mechanisms, the qualification 
of "but will usually be performed by a stakeholder in the ecosystem (public 
authority, legal system, etc.)" is too constraining.

Line 919 – 920
Commitment is closely related to obligation.  A policy represents an obligation 
but does not represent a commitment.  We are governed by many policies we are 
not committed to.  A contract is a representation of a commitment.  Commitment 
is a tighter qualification of obligation and does not fit the general level of 
section 3.1.4.  

Line 923
Figure 7 response to comment - Constraint was qualified with Policy because 
Constraint by itself was too general.  Policy Constraint does not inherit from 
Contract and Policy, UML diamond symbols are aggregations and triangles are 
inheritance.  

Line 924
The original definition of Policy is accurate.  
“A policy is an assertion promulgated by a stakeholder in such a way as to 
enforce  the assertion’s proposition.”
In the modified definition, there is a temporal dependency between “commits” and 
then “if possible and necessary” .  While this may be true it is intuitively 
contradictory. 
“enforce through stated constraints” would just be “enforce stated constraints.”  

Promulgated or “to put into effect as a regulation” captures the actions of the 
stakeholder more accurately.

Line 931
The “object of the policy” can be the stakeholder.  “or of the behavior of the 
stakeholders of the policy” is a qualified redundancy.

Lines 932 – 948
Agree with removal of Policy Topic and Policy Object but add back the following 
definitions:

Policy Constraint
A policy constraint is a measurable proposition that characterizes the 
constraint that the policy is about.

Contract
A contract represents an agreement by two or more participants to constrain 
their behavior and/or state.

Prefer the shorter definition for Contract.

Line 948
The use of “imply a desire to see constraints respected” opens another can of 
worms.  Would remove the sentence “Both policies and contracts imply …” 

Line 951 to 956
Agree with these additions.

Line 962
Agree with addition but would put a period after “action” and drop “whereas”.

Line 970
“based on the terms of the contract” is redundant.

Lines 971 – 977
Agree with changes.


Danny


      

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