A Flexible Plugin System

using System;

namespace Fadd.Logging
{
    /// <summary>
    /// Logging interface.
    /// </summary>
    public interface ILogger
    {
        /// <summary>
        /// Very detailed log messages, potentially of a high frequency and volume
        /// </summary>
        /// <param name="message">message written to the log.</param>
        void Trace(string message);

        /// <summary>
        /// Very detailed log messages, potentially of a high frequency and volume
        /// </summary>
        /// <param name="message">message written to the log.</param>
        /// <param name="exception">an exception.</param>
        void Trace(string message, Exception exception);

        /// <summary>
        /// Less detailed and/or less frequent debugging messages
        /// </summary>
        /// <param name="message">message written to the log.</param>
        void Debug(string message);

        /// <summary>
        /// Less detailed and/or less frequent debugging messages
        /// </summary>
        /// <param name="message">message written to the log.</param>
        /// <param name="exception">an exception.</param>
        void Debug(string message, Exception exception);

        /// <summary>
        /// Informational messages
        /// </summary>
        /// <param name="message">message written to the log.</param>
        void Info(string message);

        /// <summary>
        /// Informational messages
        /// </summary>
        /// <param name="message">message written to the log.</param>
        /// <param name="exception">an exception.</param>
        void Info(string message, Exception exception);

        /// <summary>
        /// Warnings which don't appear to the user of the application
        /// </summary>
        /// <param name="message">message written to the log.</param>
        void Warning(string message);

        /// <summary>
        /// Warnings which don't appear to the user of the application
        /// </summary>
        /// <param name="message">message written to the log.</param>
        /// <param name="exception">an exception.</param>
        void Warning(string message, Exception exception);

        /// <summary>
        /// Error messages
        /// </summary>
        /// <param name="message">message written to the log.</param>
        void Error(string message);

        /// <summary>
        /// Error messages
        /// </summary>
        /// <param name="message">message written to the log.</param>
        /// <param name="exception">an exception.</param>
        void Error(string message, Exception exception);

        /// <summary>
        /// Fatal error messages. After a fatal error, the application usually terminates. 
        /// </summary>
        /// <param name="message">message written to the log.</param>
        void Fatal(string message);

        /// <summary>
        /// Fatal error messages. After a fatal error, the application usually terminates. 
        /// </summary>
        /// <param name="message">message written to the log.</param>
        /// <param name="exception">an exception.</param>
        void Fatal(string message, Exception exception);
    }
}