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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.table.expressions
import org.apache.flink.api.common.typeinfo.TypeInformation
import org.apache.flink.table.api.functions.AggregateFunction
import org.apache.flink.table.api.scala._
import org.apache.flink.table.functions.utils.UserDefinedFunctionUtils.{getAccumulatorTypeOfAggregateFunction, getResultTypeOfAggregateFunction}
/**
* A class which creates a call to an aggregateFunction
*/
case class UDAGGExpression[T: TypeInformation, ACC: TypeInformation](
aggregateFunction: AggregateFunction[T, ACC]) {
/**
* Creates a call to an [[AggregateFunction]].
*
* @param params actual parameters of function
* @return a [[AggFunctionCall]]
*/
def apply(params: Expression*): AggFunctionCall = {
val resultType = getResultTypeOfAggregateFunction(
aggregateFunction, implicitly[TypeInformation[T]])
val accType = getAccumulatorTypeOfAggregateFunction(
aggregateFunction, implicitly[TypeInformation[ACC]])
AggFunctionCall(aggregateFunction, resultType, accType, params)
}
}