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https://issues.apache.org/jira/browse/HADOOP-1986?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Tom White updated HADOOP-1986:
------------------------------
Release Note:
Programs that implement the raw Mapper or Reducer interfaces will need
modification to compile with this release. For example,
class MyMapper implements Mapper {
public void map(WritableComparable key, Writable val,
OutputCollector out, Reporter reporter) throws IOException {
// ...
}
// ...
}
will need to be changed to refer to the parameterized type. For example:
class MyMapper implements Mapper<WritableComparable, Writable,
WritableComparable, Writable> {
public void map(WritableComparable key, Writable val,
OutputCollector<WritableComparable, Writable> out, Reporter reporter)
throws IOException {
// ...
}
// ...
}
Similarly implementations of the following raw interfaces will need
modification: InputFormat, OutputCollector, OutputFormat, Partitioner,
RecordReader, RecordWriter
Hadoop Flags: [Incompatible change, Reviewed] (was: [Reviewed,
Incompatible change])
> Add support for a general serialization mechanism for Map Reduce
> ----------------------------------------------------------------
>
> Key: HADOOP-1986
> URL: https://issues.apache.org/jira/browse/HADOOP-1986
> Project: Hadoop Core
> Issue Type: New Feature
> Components: mapred
> Reporter: Tom White
> Assignee: Tom White
> Fix For: 0.17.0
>
> Attachments: hadoop-serializer-v2.tar.gz,
> SequenceFileWriterBenchmark.java, SerializableWritable.java,
> serializer-v1.patch, serializer-v2.patch, serializer-v3.patch,
> serializer-v4.patch, serializer-v5.patch, serializer-v6.patch,
> serializer-v7.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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