content: /*
   * 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.calcite.adapter.hive;
  
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.sql.SqlOperator;
  import org.apache.calcite.sql.SqlOperatorBinding;
  import org.apache.calcite.sql.type.SqlReturnTypeInference;
  
  import org.apache.hadoop.hive.ql.exec.UDAF;
  import org.apache.hadoop.hive.ql.metadata.HiveException;
  import org.apache.hadoop.hive.ql.parse.SemanticException;
  import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFBridge;
  import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator;
  import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFParameterInfo;
  import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFResolver2;
  import org.apache.hadoop.hive.ql.udf.generic.SimpleGenericUDAFParameterInfo;
  import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * A HiveSqlUDAFReturnTypeInference bridges a GenericUDAFEvaluator to infer
   * the result type of a hive UDAF call
   */
  public class HiveSqlUDAFReturnTypeInference implements SqlReturnTypeInference {
  
  
    private HiveSqlUDAFReturnTypeInference() {
    }
  
    public static final HiveSqlUDAFReturnTypeInference INSTANCE =
        new HiveSqlUDAFReturnTypeInference();
  
  
    @Override public RelDataType inferReturnType(
        final SqlOperatorBinding opBinding) {
      try {
        RelDataTypeFactory factory = opBinding.getTypeFactory();
        SqlOperator sqlOperator = opBinding.getOperator();
        String opName = sqlOperator.getName();
        Class hiveUDAFClass = HiveSqlOperatorTable.instance()
            .getHiveUDAFClass(opName);
        List<RelDataTypeHolder> argsType = new ArrayList<>();
  
        for (int i = 0; i < opBinding.getOperandCount(); i++) {
          RelDataTypeHolder relDataTypeHolder;
          if (TypeInferenceUtil.isOperandConstantForHiveUDAF(hiveUDAFClass, i)) {
            //we use a pre-defined fake value here to getGenericUDAFReturnType
            Object constantValue = TypeInferenceUtil
                .HIVE_UDAF_CONSTANT_OBJECT_INSPECT_CONTEXT_MAP
                .get(hiveUDAFClass).get(i);
            relDataTypeHolder = new RelDataTypeHolder(opBinding.getOperandType(i),
                true, constantValue);
          } else {
            relDataTypeHolder = new RelDataTypeHolder(
                opBinding.getOperandType(i));
          }
          argsType.add(relDataTypeHolder);
        }
        RelDataType resultType = getGenericUDAFReturnType(
            hiveUDAFClass,
            argsType.toArray(new RelDataTypeHolder[0]), factory);
        return resultType;
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
  
    public static RelDataType getGenericUDAFReturnType(Class udafClazz,
        RelDataTypeHolder[] relDataTypeHolders, RelDataTypeFactory factory) {
      //we set isDistinct to false here,it has no effect on type inferring
      GenericUDAFEvaluator genericUDAFEvaluator = newGenericUDAFEvaluator(
          udafClazz, relDataTypeHolders, false);
      ObjectInspector objectInspector = initUDAFEvaluator(genericUDAFEvaluator,
          relDataTypeHolders);
      return TypeInferenceUtil.getRelDataType(objectInspector, factory);
    }
  
    public static GenericUDAFEvaluator newGenericUDAFEvaluator(Class udafClass,
        RelDataTypeHolder[] relDataTypeHolders, boolean isDistinct) {
      ObjectInspector[] objectInspectors = TypeInferenceUtil.getObjectInspector(
          relDataTypeHolders);
      try {
        GenericUDAFResolver2 genericUDAFResolver;
        if (GenericUDAFResolver2.class.isAssignableFrom(udafClass)) {
          genericUDAFResolver = (GenericUDAFResolver2) udafClass.newInstance();
        } else {
          UDAF udaf = (UDAF) udafClass.newInstance();
          genericUDAFResolver = new GenericUDAFBridge(udaf);
        }
        GenericUDAFParameterInfo info = new SimpleGenericUDAFParameterInfo(
            objectInspectors, isDistinct, false);
        return genericUDAFResolver.getEvaluator(info);
      } catch (IllegalAccessException | InstantiationException
          | SemanticException e) {
        throw new RuntimeException(e);
      }
    }
  
  
    public static ObjectInspector initUDAFEvaluator(
        GenericUDAFEvaluator genericUDAFEvaluator,
        RelDataTypeHolder[] relDataTypeHolders) {
      ObjectInspector[] objectInspectors = TypeInferenceUtil.getObjectInspector(
          relDataTypeHolders);
      try {
        ObjectInspector outObjectInspector = genericUDAFEvaluator.init(
            GenericUDAFEvaluator.Mode.COMPLETE, objectInspectors);
        return outObjectInspector;
      } catch (HiveException e) {
        throw new RuntimeException(e);
      }
    }
  
  }
  
  // End HiveSqlUDAFReturnTypeInference.java
  