[FLINK-5225] Add interface to override parameter types of UDTF's eval method

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Abandoned
• Component/s: Table SQL / API
• Assignee: Jark Wu
• Reporter: Jark Wu
• Created: 02/Dec/16 03:22
• Updated: 30/Jan/19 10:22
• Resolved: 30/Jan/19 10:22

Description

ScalarFunction has getParameterTypes() to be overridden if the parameter types of the eval method can not be determined automatically. This is missing in TableFunction.

This needs to implement a custom Calcite's TableFunction and override getParameters(). But currently, the FlinkTableFunctionImpl extends ReflectiveFunctionBase, the ReflectiveFunctionBase determines the parameter types of the eval method.

Issue Links

• is blocked by: FLINK-4469 Add support for user defined table function in Table API & SQL