SelectColumn.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 Deveel.Data.Serialization;

namespace Deveel.Data.Sql.Expressions {
    [Serializable]
    public sealed class SelectColumn : IPreparable, ISerializable {
        public SelectColumn(SqlExpression expression, string alias) {
            if (expression == null)
                throw new ArgumentNullException("expression");

            Expression = expression;
            Alias = alias;
        }

        public SelectColumn(SqlExpression expression)
            : this(expression, null) {
        }

        private SelectColumn(ObjectData data) {
            Expression = data.GetValue<SqlExpression>("Expression");
            Alias = data.GetString("Alias");
        }

        public SqlExpression Expression { get; private set; }

        public string Alias { get; private set; }

        public bool IsGlob {
            get {
                return (Expression is SqlReferenceExpression) &&
                       ((SqlReferenceExpression) Expression).ReferenceName.IsGlob;
            }
        }

        public bool IsAll {
            get {
                return (Expression is SqlReferenceExpression) &&
                       ((SqlReferenceExpression) Expression).ReferenceName.IsGlob &&
                       ((SqlReferenceExpression)Expression).ReferenceName.FullName == "*";
            }
        }

        public ObjectName TableName {
            get {
                var refExp = Expression as SqlReferenceExpression;
                if (refExp == null)
                    return null;

                return refExp.ReferenceName.Parent;
            }
        }

        public ObjectName ReferenceName {
            get {
                var refExp = Expression as SqlReferenceExpression;
                if (refExp == null)
                    return null;

                return refExp.ReferenceName;
            }
        }

        internal ObjectName InternalName { get; set; }

        internal ObjectName ResolvedName { get; set; }

        void ISerializable.GetData(SerializeData data) {
            data.SetValue("Expression", Expression);
            data.SetValue("Alias", Alias);
        }

        object IPreparable.Prepare(IExpressionPreparer preparer) {
            var exp = Expression;
            if (exp != null) {
                exp = exp.Prepare(preparer);
            }

            return new SelectColumn(exp, Alias);
        }

        public static SelectColumn Glob(string glob) {
            return new SelectColumn(SqlExpression.Reference(ObjectName.Parse(glob)));
        }
    }
}