Path: news.daimi.aau.dk!olm
From: olm@daimi.aau.dk (Ole Lehrmann Madsen)
Newsgroups: comp.lang.beta
Subject: Re: Alternative interaction between conc. objects
Date: 5 Feb 1998 23:47:52 GMT
Organization: DAIMI, Computer Science Dept. at Aarhus University
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In <6b9cj3$g7n$1@sessrymnir.ifi.uio.no> mikkelor@ifi.uio.no (Mikkel Orheim) writes:

>In my master thesis I'm studying concurrent objects, and arguing
>that interaction between objects (components in BETA) should
>be "loose", in the sense that a message from component A 
>should be sent to component B, and that B is to concider
>when and if this message (procedure-call) should be executed.
>(As the model presentes in "Inheritance of Synchronization 
>Constraints in Concurrent Object-Oriented Programming Languages"
>by Svend Frølund (1992).
>My question to readers of this newsgroup is as follows:
>Have you any knowledge of sutch a sceme beeing (tried) implemented 
>in BETA?
>I'm grateful for all answers, as my deadline is rapidly getting
>closer ;-)

I am not aware of implementation of a scheme similar to the one
suggested by Svend Frølund. I will, however, be very interested
in seeing such an implementation in BETA.

The BETA libraries do, however, have an implementation of
Ada-like rendezvous where an object may decide wheter or not
to accept an object. This scheme is described in section 14.3
of the BETA book (Madsen, Møller-Pedersen, Nygaard: OOP in the 
BETA programming Language, Addison Wesley/ACM Press, 1993)
In the Mjølner System, you may find the code in:

	~beta/basiclib/v1.6/basicsystemenv.bet

	pattern 'system'

and a demo example in

	~beta/basiclib/v1.6/demo/systemenv/singleBuf.bet

It is of course not the scheme suggested by Frølund.

---olm

>--
>Mikkel Orheim
>Department of Informatics, University of Oslo, Norway
>URL: http://www.stud.ifi.uio.no/~mikkelor/