beam-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (BEAM-1336) A StateSpec that doesn't care about the key shouldn't be forced to declare it as type Object
Date Fri, 21 Apr 2017 04:17:04 GMT

    [ https://issues.apache.org/jira/browse/BEAM-1336?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15978046#comment-15978046
] 

ASF GitHub Bot commented on BEAM-1336:
--------------------------------------

GitHub user kennknowles opened a pull request:

    https://github.com/apache/beam/pull/2627

    [BEAM-1336] Separate StateSpec and KeyedStateSpec

    Before this change, almost all uses of state had a type variable that
    existing only to support the esoteric use of a KeyedCombineFn in
    a state cell. Now those cases use a more verbose form of KeyedStateSpec.
    
    Be sure to do all of the following to help us incorporate your contribution
    quickly and easily:
    
     - [x] Make sure the PR title is formatted like:
       `[BEAM-<Jira issue #>] Description of pull request`
     - [ ] Make sure tests pass via `mvn clean verify`. (Even better, enable
           Travis-CI on your fork and ensure the whole test matrix passes).
     - [x] Replace `<Jira issue #>` in the title with the actual Jira issue
           number, if there is one.
     - [x] If this contribution is large, please file an Apache
           [Individual Contributor License Agreement](https://www.apache.org/licenses/icla.pdf).
    
    ---


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/kennknowles/beam StateSpec

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/beam/pull/2627.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 #2627
    
----
commit c05bda1a5922e18ab29022403f7b9e00f4cea941
Author: Kenneth Knowles <klk@google.com>
Date:   2017-04-21T03:46:37Z

    Separate StateSpec and KeyedStateSpec
    
    Before this change, almost all uses of state had a type variable that
    existing only to support the esoteric use of a KeyedCombineFn in
    a state cell. Now those cases use a more verbose form of KeyedStateSpec.

----


> A StateSpec that doesn't care about the key shouldn't be forced to declare it as type
Object
> --------------------------------------------------------------------------------------------
>
>                 Key: BEAM-1336
>                 URL: https://issues.apache.org/jira/browse/BEAM-1336
>             Project: Beam
>          Issue Type: Improvement
>          Components: sdk-java-core
>            Reporter: Kenneth Knowles
>            Assignee: Kenneth Knowles
>            Priority: Minor
>              Labels: starter
>
> In the state API as it exists today, if (as is almost often the case) you are writing
a {{StateSpec<K, StateT>}} other than a {{KeyedCombiningState}} the key type is irrelevant
and the user just has to write {{Object}} there. This was carried over from {{StateTag}} and
is an artifact of the visitor pattern there and the difficulty of getting all the types to
line up.
> I think simplifying the visitor pattern to be more of just a syntax traversal might alleviate
the issue and allow us to drop this noise from the syntax.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)

Mime
View raw message