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https://issues.apache.org/jira/browse/HDFS-8499?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14573187#comment-14573187
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Zhe Zhang commented on HDFS-8499:
---------------------------------
Many thanks for Yi and Vinay for the reviews!
bq. In BlockInfoUnderConstruction, we can implement
addStorage/removeStorage/numNodes/replaceBlock, no need to push them to
subclass.
Good point, subclass only need to implement {{convertToCompleteBlock}}
separately.
bq. In BlockInfo, convertToBlockUnderConstruction should be abstract, and
continuous/striped block implement it.
Agreed. Will address in the next rev.
bq. I think these methods you can directly move to BlockInfo itself as non of
these methods are having any difference in subclasses, at least as of now.
Actually {{BlockInfoStriped}} will implement
addStorage/removeStorage/numNodes/replaceBlock differently than
{{BlockInfoContiguous}}. So as shown below, {{BlockInfoStriped}},
{{BlockInfoContiguous}}, and {{BlockInfoUC}} each has a different
{{addStorage}} logic. In particular, {{BlockInfoUC}} just converts itself to a
complete block -- this conversion has different implementations in
{{BlockInfoUCStriped}} and {{BlockInfoUCContiguous}} -- and calls the
corresponding {{addStorage}}.
The {{convertToCompleteBlock()}} logic is necessary because
{{BlockInfoUCStriped}} no longer subclasses {{BlockStriped}} and we needs an
explicit conversion to the right type of complete block.
{code}
BlockInfo (abstract)
/ | \
BlockInfoStriped | BlockInfoContiguous
#addStorage_s | #addStorage_c
|
BlockInfoUC(abstract)
#addStorage_uc =
convertToCompleteBlock().addStorage
/ \
BlockInfoStripedUC BlockInfoContiguousUC
#convertToCompleteBlock_s #convertToCompleteBlock_c
{code}
Right now the striped classes are not in, so yes, we can put these methods in
the superclass and move them later. But I guess it's easier to put them in the
right subclasses so we can catch incoming changes during the merge process?
> Merge BlockInfoUnderConstruction into trunk
> -------------------------------------------
>
> Key: HDFS-8499
> URL: https://issues.apache.org/jira/browse/HDFS-8499
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Affects Versions: 2.7.0
> Reporter: Zhe Zhang
> Assignee: Zhe Zhang
> Attachments: HDFS-8499.00.patch
>
>
> In HDFS-7285 branch, the {{BlockInfoUnderConstruction}} interface provides a
> common abstraction for striped and contiguous UC blocks. This JIRA aims to
> merge it to trunk.
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