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https://issues.apache.org/jira/browse/HADOOP-1230?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12702547#action_12702547
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Shevek commented on HADOOP-1230:
--------------------------------
You might find that unless you pass (Context, Key, Value) as parameters to
map(), it is very hard to implement ChainedMapper, since you will have to
delegate an entire Context. It will also be very hard to do the things I want
to do with Hadoop. Unless I hear a good argument otherwise, I will submit a new
ticket.
> Replace parameters with context objects in Mapper, Reducer, Partitioner,
> InputFormat, and OutputFormat classes
> --------------------------------------------------------------------------------------------------------------
>
> Key: HADOOP-1230
> URL: https://issues.apache.org/jira/browse/HADOOP-1230
> Project: Hadoop Core
> Issue Type: Improvement
> Components: mapred
> Reporter: Owen O'Malley
> Assignee: Owen O'Malley
> Fix For: 0.20.0
>
> Attachments: context-objs-2.patch, context-objs-3.patch,
> context-objs.patch, h1230.patch, h1230.patch, h1230.patch, h1230.patch,
> h1230.patch
>
>
> This is a big change, but it will future-proof our API's. To maintain
> backwards compatibility, I'd suggest that we move over to a new package name
> (org.apache.hadoop.mapreduce) and deprecate the old interfaces and package.
> Basically, it will replace:
> package org.apache.hadoop.mapred;
> public interface Mapper extends JobConfigurable, Closeable {
> void map(WritableComparable key, Writable value, OutputCollector output,
> Reporter reporter) throws IOException;
> }
> with:
> package org.apache.hadoop.mapreduce;
> public interface Mapper extends Closable {
> void map(MapContext context) throws IOException;
> }
> where MapContext has the methods like getKey(), getValue(), collect(Key,
> Value), progress(), etc.
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