org.apache.flink.table.plan.schema.FlinkTableFunction.scala Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.flink.table.plan.schema
import org.apache.flink.table.api.functions
import org.apache.flink.table.types.DataType
import org.apache.calcite.rel.`type`.{RelDataType, RelDataTypeFactory}
import org.apache.calcite.schema.{FunctionParameter, TableFunction}
import java.lang.reflect.Type
import java.util
import java.util.Collections
/**
* A [[FlinkTableFunction]] is an implementation of [[org.apache.calcite.schema.TableFunction]].
* It is also an abstraction and instance holder of Table Function in Flink's Table API & SQL.
* We can create different kinds of [[FlinkTableFunction]] for different usages.
*
* @param tableFunction The Table Function instance
*/
abstract class FlinkTableFunction(
tableFunction: functions.TableFunction[_])
extends TableFunction {
override def getElementType(arguments: util.List[AnyRef]): Type = classOf[Array[Object]]
// we do never use the FunctionParameters, so return an empty list
override def getParameters: util.List[FunctionParameter] = Collections.emptyList()
// we do never use the getRowType, so return null
override def getRowType(
typeFactory: RelDataTypeFactory,
arguments: util.List[AnyRef]): RelDataType = null
/**
* Returns the Type for usage, i.e. code generation.
*/
def getExternalResultType(
arguments: Array[AnyRef],
argTypes: Array[Class[_]]): DataType
def getRowType(
typeFactory: RelDataTypeFactory,
arguments: Array[AnyRef],
argTypes: Array[Class[_]]): RelDataType
}