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https://issues.apache.org/jira/browse/HBASE-17312?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15879265#comment-15879265
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stack commented on HBASE-17312:
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+1 This is excellent cleanup. A few small things in rb that can go in on commit.
> [JDK8] Use default method for Observer Coprocessors
> ---------------------------------------------------
>
> Key: HBASE-17312
> URL: https://issues.apache.org/jira/browse/HBASE-17312
> Project: HBase
> Issue Type: Sub-task
> Components: Coprocessors
> Affects Versions: 2.0.0
> Reporter: Guanghao Zhang
> Assignee: Appy
> Labels: incompatible
> Attachments: HBASE-17312.master.001.patch,
> HBASE-17312.master.001.patch, HBASE-17312.master.002.patch
>
>
> In cases where one might need to use multiple observers, say region, master
> and regionserver; and the fact that only one class can be extended, it gives
> rise to following pattern:
> {noformat}
> public class BaseMasterAndRegionObserver
> extends BaseRegionObserver
> implements MasterObserver
> class AccessController
> extends BaseMasterAndRegionObserver
> implements RegionServerObserver
> {noformat}
> were BaseMasterAndRegionObserver is full copy of BaseMasterObserver.
> There is an example of simple case too where the current design fails.
> Say only one observer is needed by the coprocessor, but the design doesn't
> permit extending even that single observer (see RSGroupAdminEndpoint), that
> leads to full copy of Base...Observer class into coprocessor class leading to
> 1000s of lines of code and this ugly mix of 5 main functions with 100 useless
> functions.
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