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https://issues.apache.org/jira/browse/FLINK-5023?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15646286#comment-15646286
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ASF GitHub Bot commented on FLINK-5023:
---------------------------------------
GitHub user shixiaogang opened a pull request:
https://github.com/apache/flink/pull/2768
[FLINK-5023 & FLINK-5024] Add SimpleStateDescriptor to clarify the concepts
Changes in the definition of `State` and `StateDescriptor`:
- Add `get()` in the `State` interface.
- Remove type serializers of state values from `StateDescriptor`s.
- Add `SimpleStateDescriptor` to simplify the construction of
`ValueStateDescriptor`, `ReducingStateDescriptor` and `FoldingStateDescriptor`.
- Changes the definition of `KeyedStateBackend` and
`AbstractKeyedStateBackend` accordingly.
- Modify the implementation of `ListStateDescriptor` accordingly.
Changes in HeapStateBackend:
- Let `AbstractHeapState` not implement the `State` interface. The
`clear()` method now is removed from `AbstractHeapState`.
- Add `HeapSimpleState` to simplify the implementation of `HeapValueState`,
`HeapReducingState` and `HeapFoldingState`.
- Change the implementation of `HeapValueState`, `HeapReducingState` and
`HeapFoldingState` accordingly.
Changes in RocksDBStateBackend:
- Let `AbstractRocksDBState` not implement the `State` interface, removing
the `clear()` method. Now, `AbstractRocksDBState` does not depend on the types
of `State` and `StateDescriptor` any more.
- Add `RocksDBSimpleState` to simplify the implementation of
`RocksDBValueState`, `RocksDBReducingState` and `RocksDBFoldingState`.
- Change the implementation of `RocksDBValueState`, `RocksDBReducingState`
and `RocksDBFoldingState` accordingly.
Others:
- Update the usage of `State`s in the implementation of window operators.
- Update the usage of `State`s in unit tests.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/alibaba/flink flink-5023
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/2768.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 #2768
----
commit 007a93b454e693bc3662f540ac5f33e899ce9058
Author: xiaogang.sxg <[email protected]>
Date: 2016-11-08T02:38:22Z
Refactor the interface of State and StateDescriptor
----
> Add get() method in State interface
> -----------------------------------
>
> Key: FLINK-5023
> URL: https://issues.apache.org/jira/browse/FLINK-5023
> Project: Flink
> Issue Type: Improvement
> Components: State Backends, Checkpointing
> Reporter: Xiaogang Shi
>
> Currently, the only method provided by the State interface is `clear()`. I
> think we should provide another method called `get()` to return the
> structured value (e.g., value, list, or map) under the current key.
> In fact, the functionality of `get()` has already been implemented in all
> types of states: e.g., `value()` in ValueState and `get()` in ListState. The
> modification to the interface can better abstract these states.
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