Re: Pattern for One-Entry-Multiple-Workers Problem

Hi Stefan,

Stefan Schulz wrote:
> Hi,
>
> I am looking for a pattern to solve the following problem within
> JavaSpaces:
>
> - A Manager M writes Xi to the space.
> - Each participating Worker Wj reads Xi and produces Xij.
> - Each Wj should read a specific Xi only once.
> - Xi is written to the space, but never taken/removed.
>
> Where:
> - i and j are arbitrary numbers.
> - Xij is the result of an entry Xi processed by Worker Wj.
> - the number of produced Xi and participating Wj is not known.
> - the number of produced Xij is i x j.
>
> As far as I understood, a read on the space returns an arbitrary,
> matching entry, which (in worst case) always is the same entry. Is the
> above problem solvable within JavaSpaces at all? Or would one need
> JavaSpace05 to walk through all available matching entries and provide a
> signature/marking/logging-mechanism to check for unprocessed entries?
>

You could solve the above with an ordered distributed data structure
(see the book JavaSpaces Principels, Pattern, and Practice e.g.)
such as a distributed array, or a bit more flexible a channel. Gregg
gave an example of how to create the notion of a distributed array. I
think the next document will provide you enough information to get
started: http://www.artima.com/jini/jiniology/js6P.html.
--
Mark

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