(responding to Les Munday)
<snip> (I'm assuming you all saw the original post) Probably the key issue here (there are other minor issues) is the separation of the event being sent to an object and the response the object chooses to make on receipt of this event. Conceptually, an object generating an event does not know how the receiving object will respond. It is reasonable for the sending object to know what role the receiving object is fulfilling within its own (sender) context, and thus the sender has some (possibly very restricted) idea of the recipient's responsibilities. In the purest form of Event passing, an object may receive an event to which it does not know how to respond. Rose doesn't handle this possibility very well, and I don't have any good work-rounds (but then I've never needed any). All other work-rounds are based on the equation of the operation name and the event name, leaving it up to the users of the model to 'understand' what is meant. Typically, this requires some negotiation at design time between the event sender and the event recipient as to the meaning of the event and hence the operation name. This can be circumvented by placing tailored adaptors in all places where the meaning to sender and meaning to recipient differ. More commonly, some flexibility is sacrificed and the 'meaning' is warped to fit the particular circumstance, thereby giving the sender some inkling of what the recipient is likely to do in response. Use of 'Role' interfaces is a good way to limit the bad effects. In a collaboration, each object has collaborators acting in different Roles. Any object that implements the interfaces and fills the delegated responsibilities can act in the Role. Here the Role interface 'talks' in terms of the meaning to the sender, while the implementor of the interface can convert calls to this interface into operations 'talking' in terms of its own meaning. Role interfaces are basically formalised adaptors as mentioned in the previous paragraph. I realise this only scratches the surface of the topic, but I hope it helps. Paul Oldfield any opinions expressed herein are not necessarily those of Mentors of Cally ************************************************************************ * Rose Forum is a public venue for ideas and discussions. * For technical support, visit http://www.rational.com/support * * Admin.Subscription Requests: [EMAIL PROTECTED] * Archive of messages: http://www.rational.com/support/usergroups/rose/rose_forum.jsp * Other Requests: [EMAIL PROTECTED] * * To unsubscribe from the list, please send email * * To: [EMAIL PROTECTED] * Subject:<BLANK> * Body: unsubscribe rose_forum * *************************************************************************
