[GitHub] [flink] liyafan82 opened a new pull request #8808: [FLINK-12900][Table SQL / Runtime] Refactor the class hierarchy for BinaryFormat

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liyafan82 opened a new pull request #8808: [FLINK-12900][Table SQL / Runtime] Refactor the class hierarchy for BinaryFormat
URL: https://github.com/apache/flink/pull/8808
 
 
   
   
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   ## What is the purpose of the change
   
   The there are many classes in the class hierarchy of BinaryFormat. They share the same memory format:
   
   header + nullable bits + fixed length part + variable length part
   
   So many operations can be applied to a number of sub-classes. Currently, many such operations are implemented in each sub-class, although they implement identical functionality. 
   
   This makes the code hard to understand and maintain.
   
   In this proposal, we refactor the class hierarchy, and move common operations into the base class, leaving only one implementation for each common operation. 
   
   
   ## Brief change log
   
     - Create a class named BipartiteBinaryFormat the represents all binary format with two parts (fixed length part and variable length part)
     - Make BinaryRow, BinaryArray and NestedRow classes inherit from BipartiteBinaryFormat
     - Move common methods from sub-classes into BipartiteBinaryFormat and remove duplicated implementations
   
   
   ## Verifying this change
   
   This change is already covered by existing tests, such as *(please describe 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: (yes)
     - The runtime per-record code paths (performance sensitive): (yes)
     - Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, 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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