using System;

using System.Data.Entity;

using Westwind.Utilities;

namespace Westwind.Data.EfCodeFirst

{

/// <summary>

/// Class that creates dbContext instances and scopes them

/// either to a thread or a Web context for efficient reuse.

/// </summary>

public class DbContextFactory

{

static object WebRequestLock = new object();

/// <summary>

/// Creates a new DbContext for a specific DbContext type

/// </summary>

/// <typeparam name="TDbContext"></typeparam>

/// <returns></returns>

public static TDbContext GetDbContext<TDbContext>()

where TDbContext : DbContext, new()

{

return new TDbContext();

}

/// <summary>

/// Creates a new DbContext for a specific DbContext type with an explicit

/// connection string id

/// </summary>

/// <typeparam name="TDbContext"></typeparam>

/// <returns></returns>

public static TDbContext GetDbContext<TDbContext>(string connectionStringId)

where TDbContext : DbContext, new()

{

return Activator.CreateInstance(typeof(TDbContext), connectionStringId) as TDbContext;

}

/// <summary>

/// Retrieves a Web Request DbContext if available. If not available will use a thread scoped DbContext instead

/// </summary>

/// <typeparam name="TDbContext"></typeparam>

/// <param name="connectionStringId">Optional connection string ID from .config file</param>

/// <param name="key">optional key name of the cached item</param>

/// <returns></returns>

public static TDbContext GetWebRequestOrThreadScopedDataContext<TDbContext>(string connectionStringId = null)

where TDbContext : DbContext, new()

{

return ObjectFactory<TDbContext>.CreateWebRequestOrThreadScopedObject(connectionStringId);

}

/// <summary>

/// Creates a ASP.NET Context scoped instance of a DbContext. This static

/// method creates a single instance and reuses it whenever this method is

/// called.

///

/// This version creates an internal request specific key shared key that is

/// shared by each caller of this method from the current Web request.

/// </summary>

/// <param name="connectionStringId">optional connectionstring id to load context with</param>

/// <param name="key">Optional name of the key to store</param>

public static TDbContext GetWebRequestScopedDbContext<TDbContext>(string connectionStringId = null)

where TDbContext : DbContext, new()

{

return ObjectFactory<TDbContext>.CreateWebRequestScopedObject(connectionStringId);

}

/// <summary>

/// Creates a Thread Scoped DataContext object that can be reused.

/// The DataContext is stored in Thread local storage.

/// </summary>

/// <typeparam name="TDataContext"></typeparam>

/// <param name="connectionStringId">optional connection string ID from config file</param>

/// <param name="key">optional key name of the context to cache</param>

/// <typeparam name="TDbContext">DbContext Parameter</typeparam>

/// <returns></returns>

public static TDbContext GetThreadScopedDbContext<TDbContext>(string connectionStringId = null)

where TDbContext : DbContext, new()

{

return ObjectFactory<TDbContext>.CreateThreadScopedObject(connectionStringId);

}

}

}