Dian Fu created FLINK-10958:
-------------------------------
Summary: Add overload support for user defined function
Key: FLINK-10958
URL: https://issues.apache.org/jira/browse/FLINK-10958
Project: Flink
Issue Type: Task
Components: Table API & SQL
Reporter: Dian Fu
Assignee: Dian Fu
Currently overload is not supported in user defined function and given the
following UDF
{code:java}
class Func21 extends ScalarFunction {
def eval(p: People): String = {
p.name
}
def eval(p: Student): String = {
"student#" + p.name
}
}
class People(val name: String)
class Student(name: String) extends People(name)
class GraduatedStudent(name: String) extends Student(name)
{code}
Queries such as the following will compile failed with error msg "Found
multiple 'eval' methods which match the signature."
{code:java}
val udf = new Func21
val table = ...
table.select(udf(new GraduatedStudent("test"))) {code}
That's because overload is not supported in user defined function currently. I
think it will make sense to support overload following the java language
specification in section
[15.2|https://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.12].
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