[SPARK-28968] Add HasNumFeatures in the scala side

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Resolved
• Affects Version/s: 3.0.0
• Component/s: ML
• Assignee: Unassigned
• Reporter: Ruifeng Zheng
• Created: 04/Sep/19 02:51
• Updated: 06/Sep/19 08:53
• Resolved: 06/Sep/19 08:53

Description

In the py side, HasNumFeatures is provided and inherited by 'HashingTF' and 'FeatureHasher'.

It is reasonable to also add HasNumFeatures in the scala side.

Since '1<<18' is used by default in all place, we should add it as a default into param trait.

Issue Links

• links to: GitHub Pull Request #25671