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From Chris Wolf <>
Subject Re: idempotentConsumer is not idempotent?
Date Thu, 06 Jun 2013 15:10:35 GMT
Although you may be wishing for a strict interpretation of
"idempotent", there are also practical interpretations, e.g.
the "idempotent" option for the "file://" component - the whole
purpose of this option is to read the file only once, even if it
remains in the directory.

On Thu, Jun 6, 2013 at 10:07 AM, jannecamel <> wrote:
> At first look I was getting excited about idempotentConsumer - this would
> help me nicely in creating idempotent services.
> But looking closer, it does not seem to do what it says?
> Looks like it takes first request and processes it. Then if duplicate
> messages come, it just discards those.
> A true idempotent consumer would discard the duplicate messages AND return
> the same (cached) response as the first one got. For example if I have
> service add(x,y) and I call add(2,5) multiple times, each call should return
> 7. Now first returns 7 and duplicate ones return nothing. Or did I
> understand it wrong?
> "The term idempotent is used in mathematics to describe a function that
> produces the same result if it is applied to itself, i.e. f(x) = f(f(x)). In
> Messaging this concepts translates into the a message that has the same
> effect whether it is received once or multiple times. This means that a
> message can safely be resent without causing any problems even if the
> receiver receives duplicates of the same message."
> --
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