phoenix-core/src/main/java/org/apache/phoenix/parse/DelegateConstantToCountParseNode.java

/*
 * 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.CountAggregateFunction;
import org.apache.phoenix.expression.function.FunctionExpression;


public abstract class DelegateConstantToCountParseNode extends AggregateFunctionParseNode {

    public DelegateConstantToCountParseNode(String name, List<ParseNode> children, BuiltInFunctionInfo info) {
        super(name, children, info);
    }
    
    protected CountAggregateFunction getDelegateFunction(List<Expression> children, StatementContext context) {
        CountAggregateFunction countFunc = null;
        if (getChildren().get(0).isStateless()) {
            countFunc = (CountAggregateFunction)context.getExpressionManager().addIfAbsent(new CountAggregateFunction(children));
        }
        return countFunc;
    }
    
    @Override
    public abstract FunctionExpression create(List<Expression> children, StatementContext context) throws SQLException;

}