[FLINK-19804] Make FileSource class generic with respect to split types

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.12.0
• Component/s: Connectors / FileSystem
• Assignee: Stephan Ewen
• Reporter: Stephan Ewen
• Created: 25/Oct/20 22:19
• Updated: 08/Nov/20 22:59
• Resolved: 05/Nov/20 15:03

Description

To support sources with different split types, the FileSource class should become generic with respect to split types.

To not create too complex generic signatures for users, we should add a new class AbstractFileSource which is generic and has all the shared generic methods.

The current FileSource would be changed to extend this class for the specific split type FileSourceSplit, and thus behave exactly like it currently does.