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https://issues.apache.org/jira/browse/HDFS-8249?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Haohui Mai updated HDFS-8249:
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Attachment: HDFS-8249.004.patch
> Separate HdfsConstants into the client and the server side class
> ----------------------------------------------------------------
>
> Key: HDFS-8249
> URL: https://issues.apache.org/jira/browse/HDFS-8249
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Haohui Mai
> Assignee: Haohui Mai
> Attachments: HDFS-8249.000.patch, HDFS-8249.001.patch,
> HDFS-8249.002.patch, HDFS-8249.003.patch, HDFS-8249.004.patch
>
>
> The constants in {{HdfsConstants}} are used by both the client side and the
> server side. There are two types of constants in the class:
> 1. Constants that are used internally by the servers or not part of the APIs.
> These constants are free to evolve without breaking compatibilities. For
> example, {{MAX_PATH_LENGTH}} is used by the NN to enforce the length of the
> path does not go too long. Developers are free to change the name of the
> constants and to move it around if necessary.
> 1. Constants that are used by the clients, but not parts of the APIs. For
> example, {{QUOTA_DONT_SET}} represents an unlimited quota. The value is part
> of the wire protocol but the value is not. Developers are free to rename the
> constants but are not allowed to change the value of the constants.
> 1. Constants that are parts of the APIs. For example, {{SafeModeAction}} is
> used in {{DistributedFileSystem}}. Changing the name / value of the constant
> will break binary compatibility, but not source code compatibility.
> This jira proposes to separate the above three types of constants into
> different classes:
> * Creating a new class {{HdfsConstantsServer}} to hold the first type of
> constants.
> * Move {{HdfsConstants}} into the {{hdfs-client}} package. The work of
> separating the second and the third types of constants will be postponed in a
> separate jira.
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