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Posted to common-user@hadoop.apache.org by Deepak Nettem <de...@gmail.com> on 2012/03/31 19:32:43 UTC

ResetableIterator for Joins

Hi,

I don't quite understand the purpose of the ResetableIterator. (
http://hadoop.apache.org/common/docs/r1.0.1/api/org/apache/hadoop/mapred/join/ResetableIterator.html
).

The description says - This defines an interface to a stateful Iterator
that can replay elements added to it directly. Note that this does not
extend Iterator<http://java.sun.com/javase/6/docs/api/java/util/Iterator.html?is-external=true>.


What's a stateful iterator and why do we need to replay elements added to
it? Why does it not extend Iterator? I would appreciate any insight!

-- 
Warm Regards,
Deepak Nettem