| /* |
| * 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.beam.sdk.extensions.sql.impl; |
| |
| import java.io.Serializable; |
| import java.lang.reflect.ParameterizedType; |
| import java.util.ArrayList; |
| import java.util.List; |
| import org.apache.beam.sdk.annotations.Experimental; |
| import org.apache.beam.sdk.annotations.Internal; |
| import org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils; |
| import org.apache.beam.sdk.transforms.Combine.CombineFn; |
| import org.apache.calcite.adapter.enumerable.AggImplementor; |
| import org.apache.calcite.rel.type.RelDataType; |
| import org.apache.calcite.rel.type.RelDataTypeFactory; |
| import org.apache.calcite.schema.AggregateFunction; |
| import org.apache.calcite.schema.FunctionParameter; |
| import org.apache.calcite.schema.ImplementableAggFunction; |
| |
| /** Implement {@link AggregateFunction} to take a {@link CombineFn} as UDAF. */ |
| @Experimental |
| @Internal |
| public final class UdafImpl<InputT, AccumT, OutputT> |
| implements AggregateFunction, ImplementableAggFunction, Serializable { |
| private CombineFn<InputT, AccumT, OutputT> combineFn; |
| |
| UdafImpl(CombineFn<InputT, AccumT, OutputT> combineFn) { |
| this.combineFn = combineFn; |
| } |
| |
| public CombineFn<InputT, AccumT, OutputT> getCombineFn() { |
| return combineFn; |
| } |
| |
| @Override |
| public List<FunctionParameter> getParameters() { |
| List<FunctionParameter> para = new ArrayList<>(); |
| para.add( |
| new FunctionParameter() { |
| @Override |
| public int getOrdinal() { |
| return 0; // up to one parameter is supported in UDAF. |
| } |
| |
| @Override |
| public String getName() { |
| // not used as Beam SQL uses its own execution engine |
| return null; |
| } |
| |
| @Override |
| public RelDataType getType(RelDataTypeFactory typeFactory) { |
| ParameterizedType parameterizedType = findCombineFnSuperClass(); |
| return CalciteUtils.sqlTypeWithAutoCast( |
| typeFactory, parameterizedType.getActualTypeArguments()[0]); |
| } |
| |
| private ParameterizedType findCombineFnSuperClass() { |
| Class clazz = combineFn.getClass(); |
| while (!clazz.getSuperclass().equals(CombineFn.class)) { |
| clazz = clazz.getSuperclass(); |
| } |
| |
| if (!(clazz.getGenericSuperclass() instanceof ParameterizedType)) { |
| throw new IllegalStateException( |
| "Subclass of " + CombineFn.class + " must be parameterized to be used as a UDAF"); |
| } else { |
| return (ParameterizedType) clazz.getGenericSuperclass(); |
| } |
| } |
| |
| @Override |
| public boolean isOptional() { |
| // not used as Beam SQL uses its own execution engine |
| return false; |
| } |
| }); |
| return para; |
| } |
| |
| @Override |
| public AggImplementor getImplementor(boolean windowContext) { |
| // not used as Beam SQL uses its own execution engine |
| return null; |
| } |
| |
| @Override |
| public RelDataType getReturnType(RelDataTypeFactory typeFactory) { |
| return CalciteUtils.sqlTypeWithAutoCast(typeFactory, combineFn.getOutputType().getType()); |
| } |
| } |