[FLINK-19834] Make the TestSink reusable in all the sink related tests.

[guoweiM]

What is the purpose of the change

Make the TestSink reusable in all the sink related tests.

Brief change log

1. Change the Supplier&Function fields to normal object fields, which makes the sink serializable easily
2. Introduce the TestSink.Builder to create the test sink object.
3. Change the TestSink from a generic class to a normal class, which make extract TypeInformation possible.

Verifying this change

This change is already covered by existing tests.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable)

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Automated Checks

Last check on commit 202d1f9 (Tue Oct 27 13:39:55 UTC 2020)

Warnings:

• No documentation files were touched! Remember to keep the Flink docs up to date!
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Review Progress

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[aljoscha]

Thanks for the PR! The changes look good to me. I added one commit that changes the method names of the builder. I changed most of them to setFoo() because for me addFoo() usually indicates that a foo is added to a growing list of foo's, but here we're really just setting one. What do you think?

[aljoscha]

What's happening here?

[kl0u]

This should be removed. The base committer class uses the output although it is only needed by the Committer and not the GlobalCommitter. This does not seem to be a bug because every operator has an output but if there is no successor, the elements are simply dropped.

[guoweiM]

thanks @aljoscha and @kl0u . It would be fix in the next pr.

[kl0u]

I have some comments that have mainly to do with unused methods and base classes that can be made concrete. I have pushed my changes here (to make sure that I do not break anything :) ) https://github.com/kl0u/flink/tree/FLINK-19834.

Let me know what you think @guoweiM

[flinkbot]

CI report:

• 202d1f9 UNKNOWN
• 6386d60 Azure: FAILURE
• dac456f Azure: PENDING

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[aljoscha]

I like the formatting in @guoweiM's code more than Klou's, I think Guowei uses the EditorConfig that I use... 😅

[guoweiM]

I have some comments that have mainly to do with unused methods and base classes that can be made concrete. I have pushed my changes here (to make sure that I do not break anything :) ) https://github.com/kl0u/flink/tree/FLINK-19834.

Let me know what you think @guoweiM

Thanks @kl0u. I would look at it. :-)
I think you are right that these unused methods could removed in this pr. We could add it back when we need it.

[kl0u]

Yes @guoweiM , I think it is better to introduce a change with the commit that uses it. It is nice for commits to be self-contained so that if something goes wrong, we can easily find when and why a change was introduced. Splitting the introduction of a change from its use or its tests makes it more difficult to trace back why it was introduced and what are its implications :)

[kl0u]

+1 for merging from me as soon as AZP given green, but I think @aljoscha 's comments are not in the branch.

[kl0u]

Thanks for the work @guoweiM !

[aljoscha]

I merged this, but I renamed all the builder methods to setFoo() instead of addFoo() because they are setting a thing and not adding to a list of things.

[guoweiM]

+1 for merging from me as soon as AZP given green, but I think @aljoscha 's comments are not in the branch.

I merged this, but I renamed all the builder methods to setFoo() instead of addFoo() because they are setting a thing and not adding to a list of things.

Sorry I miss this stuff~~~~