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From John Armstrong <j...@ccri.com>
Subject Re: Usefulness of ChainMapper/ChainReducer
Date Fri, 28 Sep 2012 14:18:20 GMT
On Fri 28 Sep 2012 09:39:13 AM EDT, Harsh J wrote:
> Modularity!

Exactly! Write a mapper that operates as a filter on something about 
your keys, then use it in whatever jobs you want.  Your job needs to 
operate on data subset A? chain it with the filter mapper that picks 
out A.  Your next one needs to operate on subset B? chain it with the 
filter that picks out B!

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