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.sql.fun;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.sql.SqlAggFunction;
  import org.apache.calcite.sql.SqlFunctionCategory;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  import org.apache.calcite.util.Optionality;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  /**
   * <code>Avg</code> is an aggregator which returns the average of the values
   * which go into it. It has precisely one argument of numeric type
   * (<code>int</code>, <code>long</code>, <code>float</code>, <code>
   * double</code>), and the result is the same type.
   */
  public class SqlAvgAggFunction extends SqlAggFunction {
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a SqlAvgAggFunction.
     */
    public SqlAvgAggFunction(SqlKind kind) {
      this(kind.name(), kind);
    }
  
    SqlAvgAggFunction(String name, SqlKind kind) {
      super(name,
          null,
          kind,
          ReturnTypes.AVG_AGG_FUNCTION,
          null,
          OperandTypes.NUMERIC,
          SqlFunctionCategory.NUMERIC,
          false,
          false,
          Optionality.FORBIDDEN);
      checkArgument(SqlKind.AVG_AGG_FUNCTIONS.contains(kind),
          "unsupported sql kind");
    }
  
    @Deprecated // to be removed before 2.0
    public SqlAvgAggFunction(
        RelDataType type,
        Subtype subtype) {
      this(SqlKind.valueOf(subtype.name()));
    }
  
      //~ Methods ----------------------------------------------------------------
  
    /**
     * Returns the specific function, e.g. AVG or STDDEV_POP.
     *
     * @return Subtype
     */
    @Deprecated // to be removed before 2.0
    public Subtype getSubtype() {
      return Subtype.valueOf(kind.name());
    }
  
    /** Sub-type of aggregate function. */
    @Deprecated // to be removed before 2.0
    public enum Subtype {
      AVG,
      STDDEV_POP,
      STDDEV_SAMP,
      VAR_POP,
      VAR_SAMP
    }
  }
  