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Date: Tue, 27 Aug 2013 11:57:11 -0400
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 <CAEo-6+QcuAsFYCHMueurT1MaWV=ozhNyJ1cGbx6HcJb+f7SL+w@mail.gmail.com>
Subject: Re: MapReduce Tutorial tweak
From: Shahab Yunus <shahab.yunus@gmail.com>
To: "user@hadoop.apache.org" <user@hadoop.apache.org>
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As far as I undersstand, StringTokenizer.nextToken returns Java String type
object which does not implement the required Writable and Comparable
interfaces needed to Hadoop Mapreduce serialization and transport. The Text
class does that and is compatible and thus that is why that is being used
to wrap Java String and pass it on.

Regards,
Shahab


On Tue, Aug 27, 2013 at 11:16 AM, Andrew Pennebaker
<apennebaker@42six.com>wrote:

> In https://hadoop.apache.org/docs/stable/mapred_tutorial.html#Source+Code,
> line 16 declares:
>
> private Text word = new Text();
>
> ...
>
> But only lines 22 and 23 use this, and only to pass the value along to
> output:
>
> word.set(tokenizer.nextToken());
> output.collect(word, one);
>
> Wouldn't this be better expressed as:
>
> (no private Text word)
>
> ...
>
> output.collect(tokenizer.nextToken(), one);
>
> ?
>

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<div dir=3D"ltr">As far as I undersstand, StringTokenizer.nextToken returns=
 Java String type object which does not implement the required Writable and=
 Comparable interfaces needed to Hadoop Mapreduce serialization and transpo=
rt. The Text class does that and is compatible and thus that is why that is=
 being used to wrap Java String and pass it on.<div>
<br></div><div>Regards,</div><div>Shahab</div></div><div class=3D"gmail_ext=
ra"><br><br><div class=3D"gmail_quote">On Tue, Aug 27, 2013 at 11:16 AM, An=
drew Pennebaker <span dir=3D"ltr">&lt;<a href=3D"mailto:apennebaker@42six.c=
om" target=3D"_blank">apennebaker@42six.com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div dir=3D"ltr">In=A0<a href=3D"https://had=
oop.apache.org/docs/stable/mapred_tutorial.html#Source+Code" target=3D"_bla=
nk">https://hadoop.apache.org/docs/stable/mapred_tutorial.html#Source+Code<=
/a>, line 16 declares:<div>
<br></div><div>private Text word =3D new Text();</div>
<div><br></div><div>...</div><div><br></div><div>But only lines 22 and 23 u=
se this, and only to pass the value along to output:</div><div><br></div><d=
iv>word.set(tokenizer.nextToken());</div><div>output.collect(word, one);<br=
>

</div><div><br></div><div>Wouldn&#39;t this be better expressed as:</div><d=
iv><br></div><div>(no private Text word)</div><div><br></div><div>...</div>=
<div><br></div><div>output.collect(tokenizer.nextToken(), one);</div><div>

<br></div><div>?</div></div>
</blockquote></div><br></div>

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