Files
quantconnect--lean/Common/Data/Auxiliary/LocalDiskFactorFileProvider.cs
2018-09-07 14:36:43 -03:00

104 lines
4.2 KiB
C#

/*
* QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
* Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
*
* 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.Collections.Concurrent;
using QuantConnect.Configuration;
using QuantConnect.Interfaces;
using QuantConnect.Util;
namespace QuantConnect.Data.Auxiliary
{
/// <summary>
/// Provides an implementation of <see cref="IFactorFileProvider"/> that searches the local disk
/// </summary>
public class LocalDiskFactorFileProvider : IFactorFileProvider
{
private readonly IMapFileProvider _mapFileProvider;
private readonly ConcurrentDictionary<Symbol, FactorFile> _cache;
/// <summary>
/// Initializes a new instance of <see cref="LocalDiskFactorFileProvider"/> that uses configuration
/// to resolve an instance of <see cref="IMapFileProvider"/> from the <see cref="Composer.Instance"/>
/// </summary>
public LocalDiskFactorFileProvider()
: this(Composer.Instance.GetExportedValueByTypeName<IMapFileProvider>(Config.Get("map-file-provider", "LocalDiskMapFileProvider")))
{
}
/// <summary>
/// Initializes a new instance of the <see cref="LocalDiskFactorFileProvider"/> using the specified
/// map file provider
/// </summary>
/// <param name="mapFileProvider">The map file provider used to resolve permticks of securities</param>
public LocalDiskFactorFileProvider(IMapFileProvider mapFileProvider)
{
_mapFileProvider = mapFileProvider;
_cache = new ConcurrentDictionary<Symbol, FactorFile>();
}
/// <summary>
/// Gets a <see cref="FactorFile"/> instance for the specified symbol, or null if not found
/// </summary>
/// <param name="symbol">The security's symbol whose factor file we seek</param>
/// <returns>The resolved factor file, or null if not found</returns>
public FactorFile Get(Symbol symbol)
{
FactorFile factorFile;
if (_cache.TryGetValue(symbol, out factorFile))
{
return factorFile;
}
var market = symbol.ID.Market;
// we first need to resolve the map file to get a permtick, that's how the factor files are stored
var mapFileResolver = _mapFileProvider.Get(market);
if (mapFileResolver == null)
{
return GetFactorFile(symbol, symbol.Value, market);
}
var mapFile = mapFileResolver.ResolveMapFile(symbol.ID.Symbol, symbol.ID.Date);
if (mapFile.IsNullOrEmpty())
{
return GetFactorFile(symbol, symbol.Value, market);
}
return GetFactorFile(symbol, mapFile.Permtick, market);
}
/// <summary>
/// Checks that the factor file exists on disk, and if it does, loads it into memory
/// </summary>
private FactorFile GetFactorFile(Symbol symbol, string permtick, string market)
{
FactorFile factorFile = null;
if (FactorFile.HasScalingFactors(permtick, market))
{
factorFile = FactorFile.Read(permtick, market);
_cache.AddOrUpdate(symbol, factorFile, (s, c) => factorFile);
}
else
{
// add null value to the cache, we don't want to check the disk multiple times
// but keep existing value if it exists, just in case
_cache.AddOrUpdate(symbol, factorFile, (s, oldValue) => oldValue);
}
return factorFile;
}
}
}