org.apache.flink.table.functions.hive

Interface HiveFunction

All Known Implementing Classes:

HiveGenericUDAF, HiveGenericUDF, HiveGenericUDTF, HiveScalarFunction, HiveSimpleUDF

@Internal
public interface HiveFunction

Interface for Hive simple udf, generic udf, and generic udtf. TODO: Note: this is only a temporary interface for workaround when Flink type system and udf system rework is not finished. Should adapt to Flink type system and Flink UDF framework later on.

Method Summary

Modifier and Type	Method and Description
DataType	getHiveResultType(Object[] constantArguments, DataType[] argTypes) Get result type by arguments and argTypes.
void	setArgumentTypesAndConstants(Object[] constantArguments, DataType[] argTypes) Set arguments and argTypes for Function instance.

Method Detail

setArgumentTypesAndConstants

void setArgumentTypesAndConstants(Object[] constantArguments,
                                  DataType[] argTypes)

Set arguments and argTypes for Function instance. In this way, the correct method can be really deduced by the function instance.

Parameters:

constantArguments - arguments of a function call (only literal arguments are passed, nulls for non-literal ones)

argTypes - types of arguments

getHiveResultType

DataType getHiveResultType(Object[] constantArguments,
                           DataType[] argTypes)

Get result type by arguments and argTypes.

We can't use getResultType(Object[], Class[]). The Class[] is the classes of what is defined in eval(), for example, if eval() is "public Integer eval(Double)", the argTypes would be Class[Double]. However, in our wrapper, the signature of eval() is "public Object eval(Object... args)", which means we cannot get any info from the interface.

Parameters:

constantArguments - arguments of a function call (only literal arguments are passed, nulls for non-literal ones)

argTypes - types of arguments

Returns:

result type.