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https://issues.apache.org/jira/browse/FLINK-3042?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15409364#comment-15409364
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ASF GitHub Bot commented on FLINK-3042:
---------------------------------------
GitHub user twalthr opened a pull request:
https://github.com/apache/flink/pull/2337
[FLINK-3042] [FLINK-3060] [types] Define a way to let types create their
own TypeInformation
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please take the following check list into consideration.
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- [ ] Documentation
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This PR introduces so-called `TypeInfoFactory`s. A type information factory
allows for plugging-in user-defined TypeInformation into the Flink type system.
The factory is called during the type extraction phase if the corresponding
type has been annotated with `TypeInfo` or registered globally using
`TypeExtractor.registerFactory(Type, Class)`.
In a hierarchy of types the closest factory will be chosen while traversing
upwards, however, a globally registered factory has highest precedence.
Although this PR further increases the complexity of the `TypeExtractor`.
`TypeInfoFactory`s could simplify the code in future. We could implement
factories for all Flink built-in types and thus split up the extraction code
into type specific factories.
I haven't updated the doc yet. I will add documentation after I got
feedback.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/twalthr/flink FLINK-3042
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/2337.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #2337
----
commit 3481cf4da45292fcbf541e0ecd885a663373837b
Author: twalthr <twal...@apache.org>
Date: 2016-08-04T15:01:08Z
[FLINK-3042] [FLINK-3060] [types] Define a way to let types create their
own TypeInformation
----
> Define a way to let types create their own TypeInformation
> ----------------------------------------------------------
>
> Key: FLINK-3042
> URL: https://issues.apache.org/jira/browse/FLINK-3042
> Project: Flink
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.10.0
> Reporter: Stephan Ewen
> Assignee: Timo Walther
> Fix For: 1.0.0
>
>
> Currently, introducing new Types that should have specific TypeInformation
> requires
> - Either integration with the TypeExtractor
> - Or manually constructing the TypeInformation (potentially at every place)
> and using type hints everywhere.
> I propose to add a way to allow classes to create their own TypeInformation
> (like a static method "createTypeInfo()").
> To support generic nested types (like Optional / Either), the type extractor
> would provide a Map of what generic variables map to what types (deduced from
> the input). The class can use that to create the correct nested
> TypeInformation (possibly by calling the TypeExtractor again, passing the Map
> of generic bindings).
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