Title: RE: [soa-rm-ra] Interacting w/Services Model Updated (a start on EDA & event-driven SOA)
Thank you, Frank, it is a very good explanation.
I have looked at Jeff's "One alternative would be to show a navigable association labelled "triggers" between Event and Action". An 'association' means logical dependency and 'trigger' means, at least, action reasoning or cause. In my example and proposal, I tried to illustrate my opinion on that Event and Action association better be indirect (because of reasons listed by Frank); this is why I mentioned a 'message' between them which assumes a necessity of a "force over intent" before an Action occurs.
- Michael
-----Original Message-----
From: Francis McCabe [mailto:]
Sent: 19 March 2007 17:41
To:
Cc:
Subject: Re: [soa-rm-ra] Interacting w/Services Model Updated (a start on EDA & event-driven SOA)
Michael
You have misunderstood the connection that we looked at before here.
An event cannot cause anything. Least of all an action.
By definition, an event is a report f something that has happened
that is of interest to someone.
An action is the application of intent (I personally prefer the
term force over intent, but that riases more potential for
misunderstanding) on a target to achieve an effect.
Actions may (but then again may not if the action was unsuccessful)
give rise to events. An event may be interpreted by an agent as a
reason for initiating actions.
Messages may be used to denote events and actions. More accurately:
We use message exchange as the realization of communication of
actions and events.
More accurately still, following from Herbert Clark's notion of
joint action:
Participants send and receive messages (which are inherently
individual actions) in order to participate in joint actions (the
exchange of a message, the performance of an action, the reporting of
an event).
In our architecture, actions and events are both realized via message
exchange. A message may be used to denote an action and/or an event.
Frank
On Mar 18, 2007, at 3:13 PM, wrote:
> Replying to the Jeff's question about relationship between Event
> and Action, let me suggest that an Event can cause an Action
> directly or indirectly; plus, in some cases, one Action might be
> not enough to cause particular Action. All this looks complex.
>
> Would it be easier to define that an Event can relate to the Action
> via a Message? On the UML diagram, the 'denote' relationships might
> be bi-directional... In other words, I propose using following UML
> construct here:
>
> :EVENT ------x--------> :ACTION
> !
> !
> !
> !
> :MESSAGE
> - Michael
>
>
