[jira] [Commented] (HBASE-11210) Consider restoring Filter class back to an interface

["Jonathan Hsieh (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-11210?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14085081#comment-14085081 ] 

Jonathan Hsieh commented on HBASE-11210:
----------------------------------------

{quote}
I forgot why we turned Filter into a class (Gregory explained it, and it made sense, but I forgot).
It seems weird to have Filter as a class and have a FilterBase class. Proper design would have it that Filter is an interface and FilterBase is a convenience base implementation of it.
{quote}

The main reason for this kind of design is that if new methods are added to the interface, existing customer filters are not broken if they are derived from the FilterBase abstract class.  FilterBase would implement the new function with a empty function or default implementation as a place holder.  Not sure if this would provide binary compatibility (no recompile) or would require a recompile (but no code modification) to work, but it would be better than having to modify all your custom filters because of an additive the change.

> Consider restoring Filter class back to an interface
> ----------------------------------------------------
>
>                 Key: HBASE-11210
>                 URL: https://issues.apache.org/jira/browse/HBASE-11210
>             Project: HBase
>          Issue Type: Task
>            Reporter: Ted Yu
>
> In 0.94, Filter class is an interface.
> From Filter.java in 0.96 :
> {code}
>  * Interface for row and column filters directly applied within the regionserver.
> ...
>  * When implementing your own filters, consider inheriting {@link FilterBase} to help
>  * you reduce boilerplate.
> {code}
> We should consider restoring Filter class back to an interface.
> Lars first brought up this notion:
> https://issues.apache.org/jira/browse/HBASE-6657?focusedCommentId=13456317&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13456317
> This gives users / developers clear suggestion that custom filters should override FilterBase instead of implementing Filter directly.
> Thanks to Anoop who acknowledged this idea during offline discussion.



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