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https://issues.apache.org/jira/browse/HBASE-19746?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16447122#comment-16447122
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Chia-Ping Tsai commented on HBASE-19746:
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hi [~lars_francke] Thanks for the nice question.
{quote}So for 3.0 we remove the default implementation again?
{quote}
Not really. The API which will be removed in 3.0 is Cell#getType. We have
deprecated the Cell#getTypeByte and suggested user to implement the
Cell#getType also in 2.0. Hence, we can remove Cell#getTypeByte in 3.0.
{quote}And you do this to not break API compatibility between 1.x and 2.x?
{quote}
Yep. this issue is to keep the bc of Public class (Cell).
{quote}As far as I understand the compatibility rules in the book (which I
still have on my todo list to clarify) we don't guarantee any compatibility
between Major releases.
{quote}
IIRC, our rules to Public class is we must deprecate the API in a whole major
release before we really remove them in next major release. Also, we should
introduce the replacement for deprecated APIs.
{quote}Otherwise how would we ever add new methods to interfaces for which we
cannot provide a default implementation?
{quote}
Ya, we have discussed this issue before - how we keep the bc for the
inheritance. see HBASE-19535. If we can introduce an annotation to say the bc
of inheritance to specified Public class isn't guaranteed, our life will be
more easier. BTW, the BC is fine if the impl is from hbase.
{quote}If this is the case I'm -0 to include this. Doesn't this just shift the
problem to the next version?
{quote}
Not really. We create a room to remove the Cell#getType in 3.0.
{quote} There's nothing notifying implementors of the Cell interface of this
new default method (unlike with @deprecated things)
{quote}
I expect that hbase user should check the doc of deprecated API to find out the
replacement. The comment is shown below.
{code:java}
/**
* @return The byte representation of the KeyValue.TYPE of this cell: one of
Put, Delete, etc
* @deprecated As of HBase-2.0. Will be removed in HBase-3.0. Use {@link
#getType()}.
*/{code}
Of course, it would be better to have a more readable way to reminder user to
use new APIs.
{quote}There's also nothing in the release notes and the Javadoc for getType
also doesn't notify users about what's going to happen.
{quote}
You are right. We make a considerable change to Cell APIs (RawCell,
ExtendedCell, CelBuilder, and so on) but no fat docs are added. I can file a
Jira to write the use case to hbase doc for the new usage of Cell.
> Add default impl to Cell#getType
> --------------------------------
>
> Key: HBASE-19746
> URL: https://issues.apache.org/jira/browse/HBASE-19746
> Project: HBase
> Issue Type: Sub-task
> Reporter: Chia-Ping Tsai
> Assignee: Chia-Ping Tsai
> Priority: Critical
> Fix For: 2.0.0
>
> Attachments: HBASE-19746.v0.patch, HBASE-19746.v1.patch,
> HBASE-19746.v1.qa.patch
>
>
> Noticed this issue when migrating the app to branch-2.
> {{Cell}} is IA.Public so it should obey our compatibility rules. Not sure
> whether any related discussion had be in HBASE-19112. It worthwhile, however,
> to raise this issue again.
> FYI [~anoopsamjohn] [~ram_krish] [~stack]
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