From: Curt Hibbs <curt@...>
Date: 2001-11-30T11:42:46+09:00
Subject: [ruby-talk:27015] Re: Can someone explain TupleSpaces?

Its actually very exciting once you start to get gestalt of it. You can go
to java.sun.com and read some of the introductory material on JavaSpaces
(which is a tuplespace implementation) -- or do a google search on
JavaSpaces. Also, IBM has a tuplespace implementation which explicitly takes
a database-oriented approach to tuplespaces -- a product called TSpaces.

Curt

-----Original Message-----
From: Phil Tomson [mailto:ptkwt@shell1.aracnet.com]
Sent: Thursday, November 29, 2001 3:56 PM
To: ruby-talk ML; undisclosed-recipients:
Subject: [ruby-talk:27002] Re: Can someone explain TupleSpaces?


In article <20011130002401.A2889@michael.neumann.all>,
Michael Neumann  <neumann@s-direktnet.de> wrote:
>Phil Tomson wrote:
>>
>> First of all, what is the Tuple?  It seems to be a list of three items
>> (though I've seen more in some of the lists) - is it a way of calling a
>> method on a remote object by passing in an array of items with the first
>> element being the name of the method? (that's the theory I came up with
>> after looking at the examples - but I could be way off).
>
>Tuples come from mathematics. Unlike lists they have a predefined length.
>For example (1,2,3) is a 3-tuple, (1,"string",:3,4) a quadruple etc.
>
>A TupleSpace is a place where you can store arbitrary tuples.
>Two operations are defined on it:
>
>  - put a tuple into the TupleSpace
>  - get/remove a tuple (poss. specified by a pattern) from the TupleSpace
>
>Both operations are performed atomic (thread-safe).
>
>
>Suppose you have a server thread A and a client thread B.
>
>Thread A calls the "get" method accepting tuples matching ("add",_,_)
>where _ is a placeholder for any value. Method "get" waits until a
>matching tuple appears in the TupleSpace.
>
>The client thread B now wants to add two numbers. Therefore it puts a
>tuple ("add",2,3) into the TupleSpace. After that it waits for a tuple
>matching ("result",_).
>
>Now thread A returns from method "get", because a matching tuple
>("add",2,3) exists, and removes this tuple. In response it puts
>a tuple ("result", 5) back into the TupleSpace.
>
>Thread B gets now active again and removes the tuple ("result",5) from
>the TupleSpace.
>
>> I guess I'm looking for the 50000ft view of TupleSpace... and can someone
>> tell me why I would use them?
>
>With this architecture you can very easy communicate and synchronize
>between different
>threads or processes.
>
>Regards,
>
>  Michael
>
Thanks.  It's starting to make sense.  I almost get the feeling that a
TupleSpace is sort of like some kind of super Hash where keys and values
are interchangable  only there can be multiple values and keys
(well, it's probably a poor analogy.  I think I'm starting to see the
light, though.)

Phil