[HBASE-19092] Make Tag IA.LimitedPrivate and expose for CPs

• Type: Sub-task
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 2.0.0-beta-1, 2.0.0
• Component/s: Coprocessors
• Hadoop Flags: Incompatible change, Reviewed

Release Note

This JIRA aims at exposing Tags for Coprocessor usage.
Tag interface is now exposed to Coprocessors and CPs can make use of this interface to create their own Tags.
RawCell is a new interface that is a subtype of Cell and that is exposed to CPs. RawCell has the following APIs

List<Tag> getTags()
Optional<Tag> getTag(byte type)
byte[] cloneTags()

The above APIs helps to read tags from the Cell.

CellUtil#createCell(Cell cell, List<Tag> tags)
CellUtil#createCell(Cell cell, byte[] tags)
CellUtil#createCell(Cell cell, byte[] value, byte[] tags)
are deprecated.
If CPs want to create a cell with Tags they can use the RegionCoprocessorEnvironment#getCellBuilder() that returns an ExtendedCellBuilder.
Using ExtendedCellBuilder the CP can create Cells with Tags. Other helper methods to work on Tags are available as static APIs in Tag interface.

• Assignee: ramkrishna.s.vasudevan
• Reporter: ramkrishna.s.vasudevan
• Created: 26/Oct/17 06:18
• Updated: 17/Jun/22 05:24
• Resolved: 24/Nov/17 07:12

Description

We need to make tags as LimitedPrivate as some use cases are trying to use tags like timeline server. The same topic was discussed in dev@ and also in HBASE-18995.
Shall we target this for beta1 - cc [e-mail].
So once we do this all related Util methods and APIs should also move to LimitedPrivate Util classes.

Issue Links

• links to: Doc link.
• links to: RB link