Mailing-List: contact common-user-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: common-user@hadoop.apache.org
Received-SPF: pass (nike.apache.org: domain of deepaknettem@gmail.com
 designates 209.85.215.48 as permitted sender)
MIME-Version: 1.0
Date: Sat, 31 Mar 2012 13:32:43 -0400
Message-ID: 
 <CAEPCjf20oniCBmJYn6zr-9a+iwGR08adweOFodmE3B7xFo8DAQ@mail.gmail.com>
Subject: ResetableIterator for Joins
From: Deepak Nettem <deepaknettem@gmail.com>
To: common-user@hadoop.apache.org
Content-Type: multipart/alternative; boundary=f46d04083a9d4172d304bc8d5861

--f46d04083a9d4172d304bc8d5861
Content-Type: text/plain; charset=ISO-8859-1

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

--f46d04083a9d4172d304bc8d5861--