/*
 * 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.phoenix.parse;

import java.sql.SQLException;
import java.util.List;
import org.apache.phoenix.compile.StatementContext;
import org.apache.phoenix.expression.Expression;
import org.apache.phoenix.expression.function.*;

public class AvgAggregateParseNode extends AggregateFunctionParseNode {

  public AvgAggregateParseNode(String name, List<ParseNode> children, BuiltInFunctionInfo info) {
    super(name, children, info);
  }

  @Override
  public FunctionExpression create(List<Expression> children, StatementContext context)
    throws SQLException {
    SumAggregateFunction sumFunc;
    CountAggregateFunction countFunc = (CountAggregateFunction) context.getExpressionManager()
      .addIfAbsent(new CountAggregateFunction(children));
    if (!countFunc.isConstantExpression()) {
      sumFunc = (SumAggregateFunction) context.getExpressionManager()
        .addIfAbsent(new SumAggregateFunction(countFunc.getChildren(), null));
    } else {
      sumFunc = null;
    }

    return new AvgAggregateFunction(children, countFunc, sumFunc);
  }
}
