udpappender.cs

精通SQL Server2005项目开发

		/// <summary>
		/// Gets or sets <see cref="Encoding"/> used to write the packets.
		/// </summary>
		/// <value>
		/// The <see cref="Encoding"/> used to write the packets.
		/// </value>
		/// <remarks>
		/// <para>
		/// The <see cref="Encoding"/> used to write the packets.
		/// </para>
		/// </remarks>
		public Encoding Encoding
		{
			get { return m_encoding; }
			set { m_encoding = value; }
		}

		#endregion Public Instance Properties

		#region Protected Instance Properties

		/// <summary>
		/// Gets or sets the underlying <see cref="UdpClient" />.
		/// </summary>
		/// <value>
		/// The underlying <see cref="UdpClient" />.
		/// </value>
		/// <remarks>
		/// <see cref="UdpAppender" /> creates a <see cref="UdpClient" /> to send logging events 
		/// over a network.  Classes deriving from <see cref="UdpAppender" /> can use this
		/// property to get or set this <see cref="UdpClient" />.  Use the underlying <see cref="UdpClient" />
		/// returned from <see cref="Client" /> if you require access beyond that which 
		/// <see cref="UdpAppender" /> provides.
		/// </remarks>
		protected UdpClient Client
		{
			get { return this.m_client; }
			set { this.m_client = value; }
		}

		/// <summary>
		/// Gets or sets the cached remote endpoint to which the logging events should be sent.
		/// </summary>
		/// <value>
		/// The cached remote endpoint to which the logging events will be sent.
		/// </value>
		/// <remarks>
		/// The <see cref="ActivateOptions" /> method will initialize the remote endpoint 
		/// with the values of the <see cref="RemoteAddress" /> and <see cref="RemotePort"/>
		/// properties.
		/// </remarks>
		protected IPEndPoint RemoteEndPoint
		{
			get { return this.m_remoteEndPoint; }
			set { this.m_remoteEndPoint = value; }
		}

		#endregion Protected Instance Properties

		#region Implementation of IOptionHandler

		/// <summary>
		/// Initialize the appender based on the options set.
		/// </summary>
		/// <remarks>
		/// <para>
		/// This is part of the <see cref="IOptionHandler"/> delayed object
		/// activation scheme. The <see cref="ActivateOptions"/> method must 
		/// be called on this object after the configuration properties have
		/// been set. Until <see cref="ActivateOptions"/> is called this
		/// object is in an undefined state and must not be used. 
		/// </para>
		/// <para>
		/// If any of the configuration properties are modified then 
		/// <see cref="ActivateOptions"/> must be called again.
		/// </para>
		/// <para>
		/// The appender will be ignored if no <see cref="RemoteAddress" /> was specified or 
		/// an invalid remote or local TCP port number was specified.
		/// </para>
		/// </remarks>
		/// <exception cref="ArgumentNullException">The required property <see cref="RemoteAddress" /> was not specified.</exception>
		/// <exception cref="ArgumentOutOfRangeException">The TCP port number assigned to <see cref="LocalPort" /> or <see cref="RemotePort" /> is less than <see cref="IPEndPoint.MinPort" /> or greater than <see cref="IPEndPoint.MaxPort" />.</exception>
		public override void ActivateOptions()
		{
			base.ActivateOptions();

			if (this.RemoteAddress == null) 
			{
				throw new ArgumentNullException("The required property 'Address' was not specified.");
			} 
			else if (this.RemotePort < IPEndPoint.MinPort || this.RemotePort > IPEndPoint.MaxPort) 
			{
				throw log4net.Util.SystemInfo.CreateArgumentOutOfRangeException("this.RemotePort", (object)this.RemotePort,
					"The RemotePort is less than " + 
					IPEndPoint.MinPort.ToString(NumberFormatInfo.InvariantInfo) + 
					" or greater than " + 
					IPEndPoint.MaxPort.ToString(NumberFormatInfo.InvariantInfo) + ".");
			} 
			else if (this.LocalPort != 0 && (this.LocalPort < IPEndPoint.MinPort || this.LocalPort > IPEndPoint.MaxPort))
			{
				throw log4net.Util.SystemInfo.CreateArgumentOutOfRangeException("this.LocalPort", (object)this.LocalPort,
					"The LocalPort is less than " + 
					IPEndPoint.MinPort.ToString(NumberFormatInfo.InvariantInfo) + 
					" or greater than " + 
					IPEndPoint.MaxPort.ToString(NumberFormatInfo.InvariantInfo) + ".");
			} 
			else 
			{
				this.RemoteEndPoint = new IPEndPoint(this.RemoteAddress, this.RemotePort);
				this.InitializeClientConnection();
			}
		}

		#endregion

		#region Override implementation of AppenderSkeleton

		/// <summary>
		/// This method is called by the <see cref="AppenderSkeleton.DoAppend(LoggingEvent)"/> method.
		/// </summary>
		/// <param name="loggingEvent">The event to log.</param>
		/// <remarks>
		/// <para>
		/// Sends the event using an UDP datagram.
		/// </para>
		/// <para>
		/// Exceptions are passed to the <see cref="AppenderSkeleton.ErrorHandler"/>.
		/// </para>
		/// </remarks>
		protected override void Append(LoggingEvent loggingEvent) 
		{
			try 
			{
				Byte [] buffer = m_encoding.GetBytes(RenderLoggingEvent(loggingEvent).ToCharArray());
				this.Client.Send(buffer, buffer.Length, this.RemoteEndPoint);
			} 
			catch (Exception ex) 
			{
				ErrorHandler.Error(
					"Unable to send logging event to remote host " + 
					this.RemoteAddress.ToString() + 
					" on port " + 
					this.RemotePort + ".", 
					ex, 
					ErrorCode.WriteFailure);
			}
		}

		/// <summary>
		/// This appender requires a <see cref="Layout"/> to be set.
		/// </summary>
		/// <value><c>true</c></value>
		/// <remarks>
		/// <para>
		/// This appender requires a <see cref="Layout"/> to be set.
		/// </para>
		/// </remarks>
		override protected bool RequiresLayout
		{
			get { return true; }
		}

		/// <summary>
		/// Closes the UDP connection and releases all resources associated with 
		/// this <see cref="UdpAppender" /> instance.
		/// </summary>
		/// <remarks>
		/// <para>
		/// Disables the underlying <see cref="UdpClient" /> and releases all managed 
		/// and unmanaged resources associated with the <see cref="UdpAppender" />.
		/// </para>
		/// </remarks>
		override protected void OnClose() 
		{
			base.OnClose();

			if (this.Client != null) 
			{
				this.Client.Close();
				this.Client = null;
			}
		}

		#endregion Override implementation of AppenderSkeleton

		#region Protected Instance Methods

		/// <summary>
		/// Initializes the underlying  <see cref="UdpClient" /> connection.
		/// </summary>
		/// <remarks>
		/// <para>
		/// The underlying <see cref="UdpClient"/> is initialized and binds to the 
		/// port number from which you intend to communicate.
		/// </para>
		/// <para>
		/// Exceptions are passed to the <see cref="AppenderSkeleton.ErrorHandler"/>.
		/// </para>
		/// </remarks>
		protected virtual void InitializeClientConnection() 
		{
			try 
			{
				if (this.LocalPort == 0)
				{
					this.Client = new UdpClient();
				}
				else
				{
					this.Client = new UdpClient(this.LocalPort);
				}
			} 
			catch (Exception ex) 
			{
				ErrorHandler.Error(
					"Could not initialize the UdpClient connection on port " + 
					this.LocalPort.ToString(NumberFormatInfo.InvariantInfo) + ".", 
					ex, 
					ErrorCode.GenericFailure);

				this.Client = null;
			}
		}

		#endregion Protected Instance Methods

		#region Private Instance Fields

		/// <summary>
		/// The IP address of the remote host or multicast group to which 
		/// the logging event will be sent.
		/// </summary>
		private IPAddress m_remoteAddress;
		
		/// <summary>
		/// The TCP port number of the remote host or multicast group to 
		/// which the logging event will be sent.
		/// </summary>
		private int m_remotePort;

		/// <summary>
		/// The cached remote endpoint to which the logging events will be sent.
		/// </summary>
		private IPEndPoint m_remoteEndPoint;

		/// <summary>
		/// The TCP port number from which the <see cref="UdpClient" /> will communicate.
		/// </summary>
		private int m_localPort;

		/// <summary>
		/// The <see cref="UdpClient" /> instance that will be used for sending the 
		/// logging events.
		/// </summary>
		private UdpClient m_client;

		/// <summary>
		/// The encoding to use for the packet.
		/// </summary>
		private Encoding m_encoding = Encoding.Default;

		#endregion Private Instance Fields
	}
}