Fabian Hueske created FLINK-18683: ------------------------------------- Summary: Support @DataTypeHint for TableFunction output types Key: FLINK-18683 URL: https://issues.apache.org/jira/browse/FLINK-18683 Project: Flink Issue Type: Sub-task Components: Table SQL / API Reporter: Fabian Hueske
For ScalarFunctions, the return type of an eval method can be declared with a {{@DataTypeHint}}: {code:java} @DataTypeHint("INT") public Integer eval(Integer value) { return value * 2; }{code} This does not work for TableFunctions because the {{@DataTypeHint}} annotation refers to the {{void}} return type. Hence, {{TableFunction}} {{eval()}} methods must always be annotated with the more complex {{@FunctionHint}} method. However, I think that context, it is clear that the {{@DataTypeHint}} annotation refers to the actual return type of the table function (the type parameter of {{TableFunction<OUT>}}). We could consider allowing {{@DataTypeHint}} annotations also on {{TableFunction}} classes (defining the output type of all eval methods) and {{eval()}} methods. -- This message was sent by Atlassian Jira (v8.3.4#803005)