[ARROW-13044] [Java] Union vectors should extend ValueVector

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.1
• Fix Version/s: 5.0.0
• Component/s: Java
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/28755
• Assignee: Bryan Cutler
• Reporter: Bryan Cutler
• Created: 10/Jun/21 21:14
• Updated: 11/Jan/23 08:30
• Resolved: 15/Jun/21 04:20

Description

I was going to try using a DenseUnionVector as the underlying vector of an extension type but it's not currently possible because ExtensionTypeVector has a type constraint for the underlying storage to extend BaseValueVector and the union vectors do not extend this class.

It should be possible for UnionVector and DenseUnionVector to extend AbstractContainerVector, which is a subclass of ValueVector, then relax the type constraint for an ExtensionTypeVector to use the ValueVector interface.

Issue Links

• Dependent: ARROW-13076 [Java] Enable ExtensionType to use StructVector and UnionVector for underlying storage
• links to: GitHub Pull Request #10513