OrderByNode.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed 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.
//

using System;
using System.Linq;

namespace Deveel.Data.Sql.Parser {
    class OrderByNode : SqlNode {
        internal OrderByNode() {
        }

        public IExpressionNode Expression { get; private set; }

        public bool Ascending { get; private set; }

        protected override ISqlNode OnChildNode(ISqlNode node) {
            if (node.NodeName == "sql_reference_expression") {
                Expression = (IExpressionNode) node;
            } else if (node.NodeName == "sql_expression") {
                Expression = (IExpressionNode) node;
            } else if (node.NodeName == "sort_order") {
                GetOrder(node);
            }

            return base.OnChildNode(node);
        }

        private void GetOrder(ISqlNode node) {
            var child = node.ChildNodes.FirstOrDefault();
            if (child is SqlKeyNode) {
                var keyNode = (SqlKeyNode) child;
                if (String.Equals(keyNode.Text, "ASC", StringComparison.OrdinalIgnoreCase)) {
                    Ascending = true;
                } else if (String.Equals(keyNode.Text, "DESC", StringComparison.OrdinalIgnoreCase)) {
                    Ascending = false;
                }
            }
        }
    }
}