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https://issues.apache.org/jira/browse/HADOOP-1230?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12617491#action_12617491
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Doug Cutting commented on HADOOP-1230:
--------------------------------------
This looks great! Thanks!
A few questions:
- All the Job setters can only be meaningfully called before the job is
submitted, right? Perhaps we ought to explicitly check that, and throw an
exception when the job's already submitted?
- Shouldn't Partitioner be an abstract class instead of an interface, that
uses Math.abs(key.hashCode()) by default?
- Should OutputFormat also be an abstract class instead of an interface, like
InputFormat?
Overall it's nice to see how natural this looks!
> 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
> Attachments: context-objs-2.patch, context-objs-3.patch,
> context-objs.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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