loggermanager.cs

精通SQL Server2005项目开发

#region Copyright & License
//
// Copyright 2001-2005 The Apache Software Foundation
//
// 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.
//
#endregion

using System;
using System.Configuration;
using System.Reflection;

using log4net.Util;
using log4net.Repository;

namespace log4net.Core
{
	/// <summary>
	/// Static manager that controls the creation of repositories
	/// </summary>
	/// <remarks>
	/// <para>
	/// Static manager that controls the creation of repositories
	/// </para>
	/// <para>
	/// This class is used by the wrapper managers (e.g. <see cref="log4net.LogManager"/>)
	/// to provide access to the <see cref="ILogger"/> objects.
	/// </para>
	/// <para>
	/// This manager also holds the <see cref="IRepositorySelector"/> that is used to
	/// lookup and create repositories. The selector can be set either programmatically using
	/// the <see cref="RepositorySelector"/> property, or by setting the <c>log4net.RepositorySelector</c>
	/// AppSetting in the applications config file to the fully qualified type name of the
	/// selector to use. 
	/// </para>
	/// </remarks>
	/// <author>Nicko Cadell</author>
	/// <author>Gert Driesen</author>
	public sealed class LoggerManager
	{
		#region Private Instance Constructors

		/// <summary>
		/// Private constructor to prevent instances. Only static methods should be used.
		/// </summary>
		/// <remarks>
		/// <para>
		/// Private constructor to prevent instances. Only static methods should be used.
		/// </para>
		/// </remarks>
		private LoggerManager() 
		{
		}

		#endregion Private Instance Constructors

		#region Static Constructor

		/// <summary>
		/// Hook the shutdown event
		/// </summary>
		/// <remarks>
		/// <para>
		/// On the full .NET runtime, the static constructor hooks up the 
		/// <c>AppDomain.ProcessExit</c> and <c>AppDomain.DomainUnload</c>> events. 
		/// These are used to shutdown the log4net system as the application exits.
		/// </para>
		/// </remarks>
		static LoggerManager()
		{
			try
			{
				// Register the AppDomain events, note we have to do this with a
				// method call rather than directly here because the AppDomain
				// makes a LinkDemand which throws the exception during the JIT phase.
				RegisterAppDomainEvents();
			}
			catch(System.Security.SecurityException)
			{
				LogLog.Debug("LoggerManager: Security Exception (ControlAppDomain LinkDemand) while trying "+
					"to register Shutdown handler with the AppDomain. LoggerManager.Shutdown() "+
					"will not be called automatically when the AppDomain exits. It must be called "+
					"programmatically.");
			}

			// Dump out our assembly version into the log if debug is enabled
			LogLog.Debug(GetVersionInfo());

			// Set the default repository selector
#if NETCF
			s_repositorySelector = new CompactRepositorySelector(typeof(log4net.Repository.Hierarchy.Hierarchy));
#else

			// Look for the RepositorySelector type specified in the AppSettings 'log4net.RepositorySelector'
			string appRepositorySelectorTypeName = SystemInfo.GetAppSetting("log4net.RepositorySelector");
			if (appRepositorySelectorTypeName != null && appRepositorySelectorTypeName.Length > 0)
			{
				// Resolve the config string into a Type
				Type appRepositorySelectorType = null;
				try
				{
					appRepositorySelectorType = SystemInfo.GetTypeFromString(appRepositorySelectorTypeName, false, true);
				}
				catch(Exception ex)
				{
					LogLog.Error("LoggerManager: Exception while resolving RepositorySelector Type ["+appRepositorySelectorTypeName+"]", ex);
				}

				if (appRepositorySelectorType != null)
				{
					// Create an instance of the RepositorySelectorType
					object appRepositorySelectorObj = null;
					try
					{
						appRepositorySelectorObj = Activator.CreateInstance(appRepositorySelectorType);
					}
					catch(Exception ex)
					{
						LogLog.Error("LoggerManager: Exception while creating RepositorySelector ["+appRepositorySelectorType.FullName+"]", ex);
					}

					if (appRepositorySelectorObj != null && appRepositorySelectorObj is IRepositorySelector)
					{
						s_repositorySelector = (IRepositorySelector)appRepositorySelectorObj;
					}
					else
					{
						LogLog.Error("LoggerManager: RepositorySelector Type ["+appRepositorySelectorType.FullName+"] is not an IRepositorySelector");
					}
				}
			}

			// Create the DefaultRepositorySelector if not configured above 
			if (s_repositorySelector == null)
			{
				s_repositorySelector = new DefaultRepositorySelector(typeof(log4net.Repository.Hierarchy.Hierarchy));
			}
#endif
		}

		/// <summary>
		/// Register for ProcessExit and DomainUnload events on the AppDomain
		/// </summary>
		/// <remarks>
		/// <para>
		/// This needs to be in a separate method because the events make
		/// a LinkDemand for the ControlAppDomain SecurityPermission. Because
		/// this is a LinkDemand it is demanded at JIT time. Therefore we cannot
		/// catch the exception in the method itself, we have to catch it in the
		/// caller.
		/// </para>
		/// </remarks>
		private static void RegisterAppDomainEvents()
		{
#if !NETCF
			// ProcessExit seems to be fired if we are part of the default domain
			AppDomain.CurrentDomain.ProcessExit += new EventHandler(OnProcessExit);

			// Otherwise DomainUnload is fired
			AppDomain.CurrentDomain.DomainUnload += new EventHandler(OnDomainUnload);
#endif
		}

		#endregion Static Constructor

		#region Public Static Methods

		/// <summary>
		/// Return the default <see cref="ILoggerRepository"/> instance.
		/// </summary>
		/// <param name="repository">the repository to lookup in</param>
		/// <returns>Return the default <see cref="ILoggerRepository"/> instance</returns>
		/// <remarks>
		/// <para>
		/// Gets the <see cref="ILoggerRepository"/> for the repository specified
		/// by the <paramref name="repository"/> argument.
		/// </para>
		/// </remarks>
		[Obsolete("Use GetRepository instead of GetLoggerRepository")]
		public static ILoggerRepository GetLoggerRepository(string repository)
		{
			return GetRepository(repository);
		}

		/// <summary>
		/// Returns the default <see cref="ILoggerRepository"/> instance.
		/// </summary>
		/// <param name="repositoryAssembly">The assembly to use to lookup the repository.</param>
		/// <returns>The default <see cref="ILoggerRepository"/> instance.</returns>
		[Obsolete("Use GetRepository instead of GetLoggerRepository")]
		public static ILoggerRepository GetLoggerRepository(Assembly repositoryAssembly)
		{
			return GetRepository(repositoryAssembly);
		}

		/// <summary>
		/// Return the default <see cref="ILoggerRepository"/> instance.
		/// </summary>
		/// <param name="repository">the repository to lookup in</param>
		/// <returns>Return the default <see cref="ILoggerRepository"/> instance</returns>
		/// <remarks>
		/// <para>
		/// Gets the <see cref="ILoggerRepository"/> for the repository specified
		/// by the <paramref name="repository"/> argument.
		/// </para>
		/// </remarks>
		public static ILoggerRepository GetRepository(string repository)
		{
			if (repository == null)
			{
				throw new ArgumentNullException("repository");
			}
			return RepositorySelector.GetRepository(repository);
		}

		/// <summary>
		/// Returns the default <see cref="ILoggerRepository"/> instance.
		/// </summary>
		/// <param name="repositoryAssembly">The assembly to use to lookup the repository.</param>
		/// <returns>The default <see cref="ILoggerRepository"/> instance.</returns>
		/// <remarks>
		/// <para>
		/// Returns the default <see cref="ILoggerRepository"/> instance.
		/// </para>
		/// </remarks>
		public static ILoggerRepository GetRepository(Assembly repositoryAssembly)
		{
			if (repositoryAssembly == null)
			{
				throw new ArgumentNullException("repositoryAssembly");
			}
			return RepositorySelector.GetRepository(repositoryAssembly);
		}

		/// <summary>
		/// Returns the named logger if it exists.
		/// </summary>
		/// <param name="repository">The repository to lookup in.</param>
		/// <param name="name">The fully qualified logger name to look for.</param>
		/// <returns>
		/// The logger found, or <c>null</c> if the named logger does not exist in the
		/// specified repository.
		/// </returns>
		/// <remarks>
		/// <para>
		/// If the named logger exists (in the specified repository) then it
		/// returns a reference to the logger, otherwise it returns
		/// <c>null</c>.
		/// </para>
		/// </remarks>
		public static ILogger Exists(string repository, string name) 
		{
			if (repository == null)
			{
				throw new ArgumentNullException("repository");
			}
			if (name == null)
			{
				throw new ArgumentNullException("name");
			}
			return RepositorySelector.GetRepository(repository).Exists(name);
		}

		/// <summary>
		/// Returns the named logger if it exists.
		/// </summary>
		/// <param name="repositoryAssembly">The assembly to use to lookup the repository.</param>
		/// <param name="name">The fully qualified logger name to look for.</param>
		/// <returns>
		/// The logger found, or <c>null</c> if the named logger does not exist in the
		/// specified assembly's repository.
		/// </returns>
		/// <remarks>
		/// <para>
		/// If the named logger exists (in the specified assembly's repository) then it
		/// returns a reference to the logger, otherwise it returns
		/// <c>null</c>.
		/// </para>