Query.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;
using Deveel.Data.Diagnostics;
using Deveel.Data.Services;
using Deveel.Data.Sql;

namespace Deveel.Data {
    public sealed class Query : IQuery {
        private Dictionary<string, object> metadata;

        internal Query(ISession session) 
            : this(session, null) {
        }

        internal Query(ISession session, SqlQuery sourceQuery) {
            Session = session;
            SourceQuery = sourceQuery;

            Context = session.Context.CreateQueryContext();
            Context.RegisterInstance<IQuery>(this);

            StartedOn = DateTimeOffset.UtcNow;

            metadata = GetMetadata();
        }

        private Dictionary<string, object> GetMetadata() {
            return new Dictionary<string, object> {
                { "query.startTime", StartedOn },
                { "query.source", SourceQuery }
            };
        }

        ~Query() {
            Dispose(false);
        }

        IBlockContext IRequest.CreateBlockContext() {
            return Context.CreateBlockContext();
        }

        public IBlock CreateBlock() {
            return new Block(this);
        }

        IQuery IRequest.Query {
            get { return this; }
        }

        public IQueryContext Context { get; private set; }

        public ISession Session { get; private set; }

        public DateTimeOffset StartedOn { get; private set; }

        public SqlQuery SourceQuery { get; private set; }

        public bool HasSourceQuery {
            get { return SourceQuery != null; }
        }

        public void Dispose() {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private void Dispose(bool disposing) {
            if (disposing) {
                if (Context != null)
                    Context.Dispose();
            }

            Context = null;
            Session = null;
        }

        IContext IEventSource.Context {
            get { return Context; }
        }

        IEventSource IEventSource.ParentSource {
            get { return Session; }
        }

        IEnumerable<KeyValuePair<string, object>> IEventSource.Metadata {
            get { return metadata; }
        }
    }
}