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From "Owen O'Malley (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-1986) Add support for a general serialization mechanism for Map Reduce
Date Fri, 26 Oct 2007 20:27:51 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-1986?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12538093
] 

Owen O'Malley commented on HADOOP-1986:
---------------------------------------

{quote}
Another problem I see is that RecordSerializer only works for those classes that have constructors
that take no arguments (otherwise Class.newInstance() will fail, right?). This is also restrictive.
{quote}

I don't see it Vivek. The *RecordSerializer* would only work with classes that have 0-argument
constructors, but in general Serializers can handle arbitrary constructors for the constructed
objects. So if you have some class X that doesn't have a 0-arg constructor, just write a Serializer
that knows how to build it. 

> Add support for a general serialization mechanism for Map Reduce
> ----------------------------------------------------------------
>
>                 Key: HADOOP-1986
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1986
>             Project: Hadoop
>          Issue Type: New Feature
>          Components: mapred
>            Reporter: Tom White
>            Assignee: Tom White
>             Fix For: 0.16.0
>
>         Attachments: SerializableWritable.java, serializer-v1.patch
>
>
> Currently Map Reduce programs have to use WritableComparable-Writable key-value pairs.
While it's possible to write Writable wrappers for other serialization frameworks (such as
Thrift), this is not very convenient: it would be nicer to be able to use arbitrary types
directly, without explicit wrapping and unwrapping.

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