fixup! Replace IObjectsFactory with IServiceProvider interface

Refactor many instantiations

Author: fredericDelaporte

src/NHibernate/Cfg/SettingsFactory.cs

@@ -396,40 +396,12 @@ private static ITransactionFactory CreateTransactionFactory(IDictionary<string,
 
 		private static IQueryModelRewriterFactory CreateQueryModelRewriterFactory(IDictionary<string, string> properties)
 		{
-			var className = PropertiesHelper.GetString(Environment.QueryModelRewriterFactory, properties, null);
-
-			if (className == null)
-			{
-				try
-				{
-					var instance =
-						(IQueryModelRewriterFactory)
-						Environment.ServiceProvider.GetService(typeof(IQueryModelRewriterFactory));
-					if (instance == null)
-					{
-						return null;
-					}
-					log.Info("Query model rewriter factory factory: {0}", instance.GetType().AssemblyQualifiedName);
-					return instance;
-				}
-				catch (Exception cnfe)
-				{
-					throw new HibernateException("could not instantiate IQueryModelRewriterFactory", cnfe);
-				}
-			}
-
-			log.Info("Query model rewriter factory factory: {0}", className);
-
-			try
-			{
-				return
-					(IQueryModelRewriterFactory)
-					Environment.ServiceProvider.GetInstance(ReflectHelper.ClassForName(className));
-			}
-			catch (Exception cnfe)
-			{
-				throw new HibernateException("could not instantiate IQueryModelRewriterFactory: " + className, cnfe);
-			}
+			var instance = PropertiesHelper.GetInstance<IQueryModelRewriterFactory>(
+				Environment.QueryModelRewriterFactory,
+				properties,
+				null);
+			log.Info("Query model rewriter factory factory: '{0}'", instance?.GetType().AssemblyQualifiedName ?? "none");
+			return instance;
 		}
 	}
 }

src/NHibernate/Connection/ConnectionProvider.cs

@@ -94,35 +94,16 @@ protected virtual string GetNamedConnectionString(IDictionary<string, string> se
 		/// </exception>
 		protected virtual void ConfigureDriver(IDictionary<string, string> settings)
 		{
-			if (!settings.TryGetValue(Environment.ConnectionDriver, out var driverClass))
-			{
-				try
-				{
-					driver = (IDriver) Environment.ServiceProvider.GetService(typeof(IDriver));
-					if (driver != null)
-					{
-						driver.Configure(settings);
-						return;
-					}
-				}
-				catch (Exception e)
-				{
-					throw new HibernateException($"Could not create the driver from {typeof(IDriver)}.", e);
-				}
+			driver = PropertiesHelper.GetInstance<IDriver>(
+				Environment.ConnectionDriver,
+				settings,
+				null);
+			if (driver == null)
 				throw new HibernateException(
-					$"The {Environment.ConnectionDriver} must be specified in the NHibernate configuration section.");
-			}
+					$"The {Environment.ConnectionDriver} must be specified in the NHibernate configuration section," +
+					"or Environment.ServiceProvider must be setup in order to resolve it.");
 
-			try
-			{
-				driver =
-					(IDriver) Environment.ServiceProvider.GetInstance(ReflectHelper.ClassForName(driverClass));
-				driver.Configure(settings);
-			}
-			catch (Exception e)
-			{
-				throw new HibernateException($"Could not create the driver from {driverClass}.", e);
-			}
+			driver.Configure(settings);
 		}
 
 		/// <summary>

src/NHibernate/Connection/ConnectionProviderFactory.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 
 using NHibernate.Util;
@@ -13,48 +12,20 @@ public static class ConnectionProviderFactory
 	{
 		private static readonly INHibernateLogger log = NHibernateLogger.For(typeof(ConnectionProviderFactory));
 
-		// cannot be instantiated
 		public static IConnectionProvider NewConnectionProvider(IDictionary<string, string> settings)
 		{
-			IConnectionProvider connections;
-			if (settings.TryGetValue(Environment.ConnectionProvider, out var providerClass))
-			{
-				try
-				{
-					log.Info("Initializing connection provider: {0}", providerClass);
-					connections =
-						(IConnectionProvider)
-						Environment.ServiceProvider.GetInstance(ReflectHelper.ClassForName(providerClass));
-				}
-				catch (Exception e)
-				{
-					log.Fatal(e, "Could not instantiate connection provider");
-					throw new HibernateException("Could not instantiate connection provider: " + providerClass, e);
-				}
-			}
-			else if (settings.ContainsKey(Environment.ConnectionString) || settings.ContainsKey(Environment.ConnectionStringName))
-			{
-				connections = new DriverConnectionProvider();
-			}
-			else
-			{
-				try
-				{
-					connections = (IConnectionProvider) Environment.ServiceProvider.GetService(typeof(IConnectionProvider));
-				}
-				catch (Exception e)
-				{
-					log.Fatal(e, "Could not instantiate connection provider");
-					throw new HibernateException($"Could not instantiate connection provider: {typeof(IConnectionProvider)}", e);
-				}
-				if (connections == null)
-				{
-					log.Info("No connection provider specified, UserSuppliedConnectionProvider will be used.");
-					connections = new UserSuppliedConnectionProvider();
-				}
-			}
-			connections.Configure(settings);
-			return connections;
+			var defaultConnectionProvider =
+				settings.ContainsKey(Environment.ConnectionString) ||
+				settings.ContainsKey(Environment.ConnectionStringName)
+					? typeof(DriverConnectionProvider)
+					: typeof(UserSuppliedConnectionProvider);
+			var connectionProvider = PropertiesHelper.GetInstance<IConnectionProvider>(
+				Environment.ConnectionProvider,
+				settings,
+				defaultConnectionProvider);
+			log.Info("Connection provider: '{0}'", connectionProvider.GetType().AssemblyQualifiedName);
+			connectionProvider.Configure(settings);
+			return connectionProvider;
 		}
 	}
 }

src/NHibernate/Dialect/Dialect.cs

@@ -146,16 +146,7 @@ protected Dialect()
 		/// <returns> The specified Dialect </returns>
 		public static Dialect GetDialect()
 		{
-			string dialectName;
-			try
-			{
-				dialectName = Environment.Properties[Environment.Dialect];
-			}
-			catch (Exception e)
-			{
-				throw new HibernateException("The dialect was not set. Set the property 'dialect'.", e);
-			}
-			return InstantiateDialect(dialectName, Environment.Properties);
+			return GetDialect(Environment.Properties);
 		}
 
 		/// <summary>
@@ -169,42 +160,19 @@ public static Dialect GetDialect(IDictionary<string, string> props)
 		{
 			if (props == null)
 				throw new ArgumentNullException(nameof(props));
-			if (props.TryGetValue(Environment.Dialect, out var dialectName) == false)
-			{
-				try
-				{
-					var dialect = (Dialect) Environment.ServiceProvider.GetService(typeof(Dialect));
-					if (dialect != null)
-					{
-						return dialect;
-					}
-				}
-				catch (Exception e)
-				{
-					throw new HibernateException($"Could not instantiate dialect class {typeof(Dialect)}", e);
-				}
+			if (props.TryGetValue(Environment.Dialect, out var dialectName) && dialectName == null)
+				props = Environment.Properties;
+			
+			var dialect = PropertiesHelper.GetInstance<Dialect>(
+				Environment.Dialect,
+				props,
+				null);
+
+			if (dialect == null)
 				throw new InvalidOperationException("Could not find the dialect in the configuration");
-			}
-			if (dialectName == null)
-			{
-				return GetDialect();
-			}
-
-			return InstantiateDialect(dialectName, props);
-		}
 
-		private static Dialect InstantiateDialect(string dialectName, IDictionary<string, string> props)
-		{
-			try
-			{
-				var dialect = (Dialect) Environment.ServiceProvider.GetInstance(ReflectHelper.ClassForName(dialectName));
-				dialect.Configure(props);
-				return dialect;
-			}
-			catch (Exception e)
-			{
-				throw new HibernateException("Could not instantiate dialect class " + dialectName, e);
-			}
+			dialect.Configure(props);
+			return dialect;
 		}
 
 		/// <summary>

src/NHibernate/Linq/Functions/LinqToHqlGeneratorsRegistryFactory.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 
 using NHibernate.Util;
@@ -12,30 +11,12 @@ public sealed class LinqToHqlGeneratorsRegistryFactory
 
 		public static ILinqToHqlGeneratorsRegistry CreateGeneratorsRegistry(IDictionary<string, string> properties)
 		{
-			if (properties.TryGetValue(Environment.LinqToHqlGeneratorsRegistry, out var registry))
-			{
-				try
-				{
-					log.Info("Initializing LinqToHqlGeneratorsRegistry: {0}", registry);
-					return (ILinqToHqlGeneratorsRegistry) Environment.ServiceProvider.GetInstance(ReflectHelper.ClassForName(registry));
-				}
-				catch (Exception e)
-				{
-					log.Fatal(e, "Could not instantiate LinqToHqlGeneratorsRegistry");
-					throw new HibernateException("Could not instantiate LinqToHqlGeneratorsRegistry: " + registry, e);
-				}
-			}
-			try
-			{
-				return (ILinqToHqlGeneratorsRegistry)
-				       Environment.ServiceProvider.GetService(typeof(ILinqToHqlGeneratorsRegistry)) ??
-				       new DefaultLinqToHqlGeneratorsRegistry();
-			}
-			catch (Exception e)
-			{
-				log.Fatal(e, "Could not instantiate LinqToHqlGeneratorsRegistry");
-				throw new HibernateException($"Could not instantiate LinqToHqlGeneratorsRegistry: {typeof(ILinqToHqlGeneratorsRegistry)}", e);
-			}
+			var instance = PropertiesHelper.GetInstance<ILinqToHqlGeneratorsRegistry>(
+				Environment.LinqToHqlGeneratorsRegistry,
+				properties,
+				typeof(DefaultLinqToHqlGeneratorsRegistry));
+			log.Info("LinqToHqlGeneratorsRegistry: '{0}'", instance.GetType().AssemblyQualifiedName);
+			return instance;
 		}
 	}
 }

src/NHibernate/Util/PropertiesHelper.cs

@@ -10,10 +10,10 @@ public static class PropertiesHelper
 	{
 		public static bool GetBoolean(string property, IDictionary<string, string> properties, bool defaultValue)
 		{
-			string toParse;
-			properties.TryGetValue(property, out toParse);
-			bool result;
-			return bool.TryParse(toParse, out result) ? result : defaultValue;
+			if (properties == null)
+				throw new ArgumentNullException(nameof(properties));
+			properties.TryGetValue(property, out var toParse);
+			return bool.TryParse(toParse, out var result) ? result : defaultValue;
 		}
 
 		public static bool GetBoolean(string property, IDictionary<string, string> properties)
@@ -23,33 +23,34 @@ public static bool GetBoolean(string property, IDictionary<string, string> prope
 
 		public static byte? GetByte(string property, IDictionary<string, string> properties, byte? defaultValue)
 		{
-			string toParse;
-			properties.TryGetValue(property, out toParse);
-			byte result;
-			return byte.TryParse(toParse, out result) ? result : defaultValue;
+			if (properties == null)
+				throw new ArgumentNullException(nameof(properties));
+			properties.TryGetValue(property, out var toParse);
+			return byte.TryParse(toParse, out var result) ? result : defaultValue;
 		}
 
 		public static int GetInt32(string property, IDictionary<string, string> properties, int defaultValue)
 		{
-			string toParse;
-			properties.TryGetValue(property, out toParse);
-			int result;
-			return int.TryParse(toParse, out result) ? result : defaultValue;
+			if (properties == null)
+				throw new ArgumentNullException(nameof(properties));
+			properties.TryGetValue(property, out var toParse);
+			return int.TryParse(toParse, out var result) ? result : defaultValue;
 		}
 
 		public static long GetInt64(string property, IDictionary<string, string> properties, long defaultValue)
 		{
-			string toParse;
-			properties.TryGetValue(property, out toParse);
-			long result;
-			return long.TryParse(toParse, out result) ? result : defaultValue;
+			if (properties == null)
+				throw new ArgumentNullException(nameof(properties));
+			properties.TryGetValue(property, out var toParse);
+			return long.TryParse(toParse, out var result) ? result : defaultValue;
 		}
 
 		public static string GetString(string property, IDictionary<string, string> properties, string defaultValue)
 		{
-			string value;
-			properties.TryGetValue(property, out value);
-			if(value == string.Empty)
+			if (properties == null)
+				throw new ArgumentNullException(nameof(properties));
+			properties.TryGetValue(property, out var value);
+			if (value == string.Empty)
 			{
 				value = null;
 			}
@@ -58,10 +59,11 @@ public static string GetString(string property, IDictionary<string, string> prop
 
 		public static IDictionary<string, string> ToDictionary(string property, string delim, IDictionary<string, string> properties)
 		{
-			IDictionary<string, string> map = new Dictionary<string, string>();
+			if (properties == null)
+				throw new ArgumentNullException(nameof(properties));
+			var map = new Dictionary<string, string>();
 
-			string propValue;
-			if (properties.TryGetValue(property, out propValue))
+			if (properties.TryGetValue(property, out var propValue))
 			{
 				var tokens = new StringTokenizer(propValue, delim, false);
 				using (var en = tokens.GetEnumerator())
@@ -84,28 +86,32 @@ public static IDictionary<string, string> ToDictionary(string property, string d
 		/// <param name="property">The configuration property name.</param>
 		/// <param name="properties">The configuration properties.</param>
 		/// <param name="defaultType">The default type to instantiate.</param>
-		/// <returns>The instance of the <typeparamref name="TService"/> type.</returns>
-		public static TService GetInstance<TService>(string property, IDictionary<string, string> properties, System.Type defaultType)
+		/// <returns>The instance of the <typeparamref name="TService"/> type, or <see langword="null" /> if none is
+		/// configured and <paramref name="defaultType"/> is <see langword="null" />.</returns>
+		public static TService GetInstance<TService>(
+			string property, IDictionary<string, string> properties, System.Type defaultType) where TService : class
 		{
 			var className = GetString(property, properties, null);
+			System.Type type = null;
 			try
 			{
-				if (className != null)
-				{
-					return (TService) Cfg.Environment.ServiceProvider.GetInstance(ReflectHelper.ClassForName(className));
-				}
+				type = className != null
+					? ReflectHelper.ClassForName(className)
+					: typeof(TService);
 
-				var instance = (TService) Cfg.Environment.ServiceProvider.GetService(typeof(TService));
+				var instance = (TService) Cfg.Environment.ServiceProvider.GetService(type);
 				if (instance != null)
 				{
 					return instance;
 				}
 
-				return (TService) Cfg.Environment.ServiceProvider.GetInstance(defaultType);
+				type = defaultType;
+				return defaultType != null ? (TService) Cfg.Environment.ServiceProvider.GetInstance(defaultType) : null;
 			}
 			catch (Exception e)
 			{
-				throw new HibernateException($"could not instantiate {typeof(TService).Name}: {className ?? defaultType.AssemblyQualifiedName}", e);
+				throw new HibernateException(
+					$"Could not instantiate {typeof(TService).Name}: {type?.AssemblyQualifiedName ?? className}", e);
 			}
 		}
 	}