QueryableTable.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;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;

namespace Deveel.Data.Linq {
    class QueryableTable<T> : IOrderedQueryable<T> {
        public QueryableTable(TableQueryProvider provider) {
            Provider = provider;
            Expression = Expression.Constant(this);
        }

        public QueryableTable(TableQueryProvider provider, Expression expression) {
            if (provider == null)
                throw new ArgumentNullException("provider");
            if (expression == null)
                throw new ArgumentNullException("expression");

            if (!typeof(IQueryable<T>).IsAssignableFrom(expression.Type))
                throw new ArgumentException("Invalid expression type.", "expression");

            Provider = provider;
            Expression = expression;
        }

        IEnumerator IEnumerable.GetEnumerator() {
            return ((IEnumerable) Provider.Execute(Expression)).GetEnumerator();
        }

        public Expression Expression { get; private set; }

        public Type ElementType {
            get { return typeof (T); }
        }

        public IQueryProvider Provider { get; private set; }

        public IEnumerator<T> GetEnumerator() {
            return ((IEnumerable<T>) Provider.Execute<T>(Expression)).GetEnumerator();
        }

        public override string ToString() {
            return ((TableQueryProvider) Provider).GetQueryText(Expression);
        }
    }
}