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https://issues.apache.org/jira/browse/HADOOP-1230?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12717179#action_12717179
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Thomas Kathmann edited comment on HADOOP-1230 at 6/8/09 2:56 AM:
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I would recommend the following additions:
- getReader() to MapContext. Sometimes you need more info from the reader than
what you get by other methods, and the current implementation gives you no
chance to access - besides awkward workarounds by registering readers in static
variables.
- Adding setJar() to Job. If you have a project that schedules and runs hadoop
jobs, you don't want the scheduler to use the same jar as the one which is
distributed to run the jobs. This allows you to redeploy the jar containing the
job without any additional effort to load it into the scheduler.
Also what happens to the hadoop.streaming classes?
was (Author: thomas.kathmann):
I would recommend the following additions:
- getReader() to MapContext. Sometimes you need more info from the reader than
what you get by other methods, and the current implementation gives you no
chance to access - besides awkward workarounds by registering readers in static
variables.
- Adding setJar() to Job. If you have a project that schedules and runs hadoop
jobs, you don't want the scheduler to use the same jar as the one which is
distributed to run the jobs. This allows you to redeploy the jar containing the
job without any additional effort to load it into the scheduler.
> 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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