log4m.m

classdef log4m < handle 
    %LOG4M This is a simple logger based on the idea of the popular log4j.
    %
    % Description: Log4m is designed to be relatively fast and very easy to
    % use. It has been designed to work well in a matlab environment.
    % Please contact me (info below) with any questions or suggestions!
    % 
    %
    % Author: 
    %       Luke Winslow <lawinslow@gmail.com>
    % Heavily modified version of 'log4matlab' which can be found here:
    %       http://www.mathworks.com/matlabcentral/fileexchange/33532-log4matlab
    %
    
    properties (Constant)
        ALL = 0;
        TRACE = 1;
        DEBUG = 2;
        INFO = 3;
        WARN = 4;
        ERROR = 5;
        FATAL = 6;
        OFF = 7;
    end
        
    properties(Access = protected)
        logger;
        lFile;
    end
    
    properties(SetAccess = protected)
        fullpath = 'log4m.log';  %Default file
        commandWindowLevel = log4m.ALL;
        logLevel = log4m.INFO;
        fid = 0;
    end
    
    methods (Static)
        function obj = getLogger( logPath )
            %GETLOGGER Returns instance unique logger object.
            %   PARAMS:
            %       logPath - Relative or absolute path to desired logfile.
            %   OUTPUT:
            %       obj - Reference to signular logger object.
            %
            
            if(nargin == 0)
                logPath = 'log4m.log';
            elseif(nargin > 1)
                error('getLogger only accepts one parameter input');
            end
            
            persistent localObj;

            if isempty(localObj) || ~isvalid(localObj)
                localObj = log4m(logPath);
            end
            obj = localObj;
        end
        
        function testSpeed( logPath )
            %TESTSPEED Gives a brief idea of the time required to log.
            %
            %   Description: One major concern with logging is the
            %   performance hit an application takes when heavy logging is
            %   introduced. This function does a quick speed test to give
            %   the user an idea of how various types of logging will
            %   perform on their system.
            %
            
            L = log4m.getLogger(logPath);
            
            
            disp('1e5 logs when logging only to command window');
            
            L.setCommandWindowLevel(L.TRACE);
            L.setLogLevel(L.OFF);
            tic;
            for i=1:1e5
                L.trace('log4mTest','test');
            end
            
            disp('1e5 logs when logging only to command window');
            toc;
            
            disp('1e6 logs when logging is off');
            
            L.setCommandWindowLevel(L.OFF);
            L.setLogLevel(L.OFF);
            tic;
            for i=1:1e6
                L.trace('log4mTest','test');
            end
            toc;
            
            disp('1e4 logs when logging to file');
            
            L.setCommandWindowLevel(L.OFF);
            L.setLogLevel(L.TRACE);
            tic;
            for i=1:1e4
                L.trace('log4mTest','test');
            end
            toc;
            
        end
    end
    
    
%% Public Methods Section %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    methods       

        function setCommandWindowLevel(self,loggerIdentifier)
            self.commandWindowLevel = loggerIdentifier;
        end


        function setLogLevel(self,logLevel)
            self.logLevel = logLevel;
        end
        

%% The public Logging methods %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
        function trace(self, message, varargin)
            self.writeLog(self.TRACE,message,varargin);
        end
        
        function debug(self, message, varargin)
            self.writeLog(self.DEBUG,message,varargin);
        end
        
 
        function info(self, message, varargin)
            self.writeLog(self.INFO,message,varargin);
        end
        

        function warn(self, message, varargin)
            self.writeLog(self.WARN,message,varargin);
        end
        

        function error(self, message, varargin)
            self.writeLog(self.ERROR,message,varargin);
        end
        

        function fatal(self, message, varargin)
            self.writeLog(self.FATAL,message,varargin);
        end
        
    end

%% Private Methods %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   Unless you're modifying this, these should be of little concern to you.
    methods (Access = private)
        
        function self = log4m(logPath)
             self.fid = fopen(logPath, 'wt');
        end
        
%% WriteToFile        
        function writeLog(self,level,message,args)
            
            % If necessary write to command window
            if( self.commandWindowLevel <= level )
                fprintf('%s\n', sprintf(message, args{:}));
            end
            
            %If currently set log level is too high, just skip this log
            if(self.logLevel > level)
                return;
            end 
            
            % set up our level string
            switch level
                case{self.TRACE}
                    levelStr = 'TRACE';
                case{self.DEBUG}
                    levelStr = 'DEBUG';
                case{self.INFO}
                    levelStr = 'INFO';
                case{self.WARN}
                    levelStr = 'WARN';
                case{self.ERROR}
                    levelStr = 'ERROR';
                case{self.FATAL}
                    levelStr = 'FATAL';
                otherwise
                    levelStr = 'UNKNOWN';
            end

            % Append new log to log file
            try
                msg = sprintf(message, args{:});
                now_str = datestr(now,'yyyy-mm-dd HH:MM:SS.FFF');
                fprintf(self.fid, '%s %s\n', [now_str, ' ', levelStr, ' - '], msg);
            catch ME_1
                display(ME_1);
            end
        end
    end
    
end