SimpleLog/SimpleLog/Src/DefaultMessageHandler.cs

using System;
using System.Collections.Generic;
using SimpleLog.Framework;

namespace SimpleLog {
	/// <summary>
	/// Default message handler
	/// </summary>
	public class DefaultMessageHandler : IMessageHandler, IMessageFormatter {

		#region Protected members
		/// <summary>
		/// Date format of this message handler
		/// </summary>
		protected string dateFormat;
		/// <summary>
		/// Line terminator used by this message handler
		/// </summary>
		protected string lineTerminator;
		/// <summary>
		/// Context string used by this message handler
		/// </summary>
		protected string context;
		/// <summary>
		/// Message component delimiter (e.g. in the message
		/// "2009-04-17 [context] This is the message" a space
		/// is the delimiter)
		/// </summary>
		protected string delimiter;
		#endregion

		#region Constructors
		/// <summary>
		/// Creates a DefaultMessageHandler with the default settings
		/// </summary>
		public DefaultMessageHandler() : this("") {

		}

		/// <summary>
		/// Creates a DefaultMessageHandler with the specified context
		/// </summary>
		/// <param name="context">Context of the message handler</param>
		public DefaultMessageHandler(string context) : this(context, null, SimpleLog.Framework.LineTerminator.Unix, "\t") {

		}

		/// <summary>
		/// Creates a DefaultMessageHandler
		/// </summary>
		/// <param name="context">Context of the message handler</param>
		/// <param name="dateFormat">Date format suitable as an argument to string.Format()</param>
		/// <param name="lineTerminator">The line terminator</param>
		/// <param name="delimiter">The string that delimits each part of the log message</param>
		public DefaultMessageHandler(string context, string dateFormat, string lineTerminator, string delimiter) {
			this.DateFormat     = dateFormat;
			this.LineTerminator = lineTerminator;
			this.Context        = context;
			this.Delimiter      = delimiter;
		}
		#endregion

		#region IMessageHandler Members
		/// <summary>
		/// Formats a log message
		/// </summary>
		/// <param name="message">The message to log</param>
		/// <param name="level">The log level of the message</param>
		/// <returns>The formatted message</returns>
		public virtual string FormatLogMessage(string message, LogLevel level) {
			List<string> messageData = new List<string>();
			messageData.Add(string.Format("{0:" + this.DateFormat + "}", DateTime.Now));
			messageData.Add(level.ToString().ToUpper());
			if (!string.IsNullOrEmpty(this.Context)) {
				messageData.Add("[" + this.Context + "]");
			}
			messageData.Add(message);

			return string.Join(this.Delimiter, messageData.ToArray()) + this.LineTerminator;
		}

		/// <summary>
		/// Converts the message object to a string. If the message object
		/// is an exception, the new message is a concatenation of the Message
		/// and StackTrace. Otherwise, the object's ToString() method is used for 
		/// conversion.
		/// </summary>
		/// <param name="message">The message object to convert</param>
		/// <returns>The message as a string</returns>
		public virtual string ConvertMessageToString(object message) {
			string msg = null;
			if (message is Exception) {
				Exception e = (Exception)message;
				msg = e.Message + this.LineTerminator + e.StackTrace;
			}
			else {
				msg = message.ToString();
			}
			return msg;
		}

		/// <summary>
		/// Gets or sets the context of this message handler
		/// </summary>
		public string Context {
			get {
				return this.context;
			}
			set {
				this.context = value;
			}
		}
		#endregion

		#region Accessors
		/// <summary>
		/// Gets or sets the delimiter used to separate log message data
		/// </summary>
		public string Delimiter {
			get {
				return this.delimiter;
			}
			set {
				this.delimiter = value;
			}
		}
		#endregion

		#region IMessageFormatter members
		/// <summary>
		/// Gets or sets the date format
		/// </summary>
		public string DateFormat {
			get {
				return this.dateFormat;
			}
			set {
				this.dateFormat = value;
			}
		}

		/// <summary>
		/// Gets or sets the line terminator
		/// </summary>
		public string LineTerminator {
			get {
				return this.lineTerminator;
			}
			set {
				if (!Util.LineTerminatorIsValid(value)) {
					throw new ArgumentException("Invalid line terminator; see SimpleLog.LineTerminator for valid line terminators");
				}

				this.lineTerminator = value;
			}
		}
		#endregion

	}
}