[
https://issues.apache.org/jira/browse/MAPREDUCE-954?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12753147#action_12753147
]
Doug Cutting commented on MAPREDUCE-954:
----------------------------------------
> to protect users who need to implement custom context objects against changes
> to the interfaces
I'm confused.
Interfaces differ from abstract classes in two ways:
# Abstract classes can have (default) method implementations. This permits
APIs to evolve without breaking callers or implementors.
# Multiple interfaces can be inherited.
The primary advantage of interfaces is the second. But if implementations
extend a base class this advantage is voided. What then is the utility of the
interface?
> The new interface's Context objects should be interfaces
> --------------------------------------------------------
>
> Key: MAPREDUCE-954
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-954
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: client
> Reporter: Owen O'Malley
> Assignee: Arun C Murthy
> Fix For: 0.21.0
>
> Attachments: MAPREDUCE-954.patch
>
>
> When I was doing HADOOP-1230, I was persuaded to make the Context objects as
> classes. I think that was a serious mistake. It caused a lot of information
> leakage into the public classes.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
