Re: [soa-rm-ra] point of action

[Ken Laskey <klaskey@mitre.org>]

Some comments from Frank that didn't get back to the list:

Ken:

 The POA *is* the action as it is applied.

 If the service is the glove, the POA is the iron fist:)

 Different people have different definitions of action, (try define:action in google). None of these definitions is all that satisfactory to me.

 My definition is adapted from John Sowa:

Action: the application of force by an agent on an object with the intention of achieving an effect.

 I.e., its a kind of event. The POA is a characterization of that event. (One reason I like this definition is that is includes all human actions but excludes rocks rolling down the hill hitting other rocks.)

 The service interface is the characterization of what it means to perform an action. It is not the action itself though.

 Hope that this throws a little light on the matter.

Frank

Per Danny's response, I think he caught my question well with the final line of his response below:

One question

we can ask is can we identify a point of action

meaningful to the reference architecture that would

not have a service interface?

Ken

On Aug 17, 2006, at 1:55 AM, Danny Thornton wrote:

To draw another analogy for the point of action, I

know your mind will be the point of action for

processing this e-mail as you read the e-mail.  The

e-mail address and the english language is like a

service interface. 

The SOA has many points of action, each point of

action potentially affecting many other points of

action.  We can identify points of action in a SOA

relevant to the reference architecture.  One question

we can ask is can we identify a point of action

meaningful to the reference architecture that would

not have a service interface?

Danny

--- Ken Laskey <klaskey@mitre.org> wrote:

The following are from my notes at the ftf

Point of Action (poa)

-       Frank: anchoring mechanism for numerous

things, e.g. policy  

enforcement, evaluating needs & capabilities

-       Ken: how does poa relate to service

interface?  Frank:  

service interface includes actions you can perform;

each instance of  

use consists of performing action; actual action is

poa; interface  

vs. poa is class vs. instance relationship; the

physical action is  

the point of action

-       [Ken] Given a policy is a desire of one

participant and an  

agreement as part of the execution context for

participants to abide  

by that policy (i.e. the other participant(s) agree

to make that  

policy theirs), the policy enforcement point becomes

the point of  

action for enforcing the agreed-upon policy.

-       [Frank alternative] A policy is a constraint

that represents  

the desire of a participant. A contract is a

constraint that  

represents the agreed desires of two or more

participants. A [policy]  

enforcement point is the point of action for

enforcing constraints  

that represent either policies or contracts.

I've reread this and am still having problems

differentiating between  

service interface and point of action.  It appears

that poa is more  

general because it is the location to which a user

would send a  

command for action.  If the receiver is a service,

then the poa would  

seem to be the service interface.  In the policy

example, if the  

enforcement mechanism is accessed through a service,

the PEP could be  

said to have a service interface.

I still seem to be missing something.

Ken

---

Ken Laskey

MITRE Corporation, M/S H305     phone:  703-983-7934

7515 Colshire Drive                        fax:     

  703-983-1379

McLean VA 22102-7508

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---

Ken Laskey

MITRE Corporation, M/S H305     phone:  703-983-7934

7515 Colshire Drive                        fax:        703-983-1379

McLean VA 22102-7508