SelectStatement.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.Collections.Generic;

using Deveel.Data.Serialization;
using Deveel.Data.Sql.Expressions;
using Deveel.Data.Sql.Query;

namespace Deveel.Data.Sql.Statements {
    public sealed class SelectStatement : SqlStatement, IPreparableStatement {
        public SelectStatement(SqlQueryExpression queryExpression) 
            : this(queryExpression, null) {
        }

        public SelectStatement(SqlQueryExpression queryExpression, IEnumerable<SortColumn> orderBy) {
            if (queryExpression == null)
                throw new ArgumentNullException("queryExpression");

            QueryExpression = queryExpression;
            OrderBy = orderBy;
        }

        public SqlQueryExpression QueryExpression { get; private set; }

        public IEnumerable<SortColumn> OrderBy { get; set; }

        public QueryLimit Limit { get; set; }

        IStatement IPreparableStatement.Prepare(IRequest context) {
            var queryPlan = context.Query.Context.QueryPlanner().PlanQuery(new QueryInfo(context, QueryExpression, OrderBy, Limit));
            return new Prepared(queryPlan);
        }

        #region Prepared

        [Serializable]
        class Prepared : SqlStatement {
            public Prepared(IQueryPlanNode queryPlan) {
                QueryPlan = queryPlan;
            }

            private Prepared(ObjectData data) {
                QueryPlan = data.GetValue<IQueryPlanNode>("QueryPlan");
            }

            public IQueryPlanNode QueryPlan { get; private set; }

            protected override void GetData(SerializeData data) {
                data.SetValue("QueryPlan", QueryPlan);
            }

            protected override void ExecuteStatement(ExecutionContext context) {
                var result = QueryPlan.Evaluate(context.Request);
                context.SetResult(result);
            }
        }

        #endregion
    }
}