Hi --

On Fri, 24 Jul 2009, Venkat Akkineni wrote:

> Hi
>
>    I have created a class with a class method. I am trying to call it
> from a different class and I get the "uninitialized constant" error.
> Could some body help me out.
>
>> Class with class method
>
> # To change this template, choose Tools | Templates
> # and open the template in the editor.
>
> require "log4r/logger"
>
> class XELogger < Log4r::Logger
>
>  def XELogger.get(fullname)
>    begin
>      return self.superclass.get(fullname)
>    rescue NameError
>      return Log4r::Logger.new(fullname , nil , true , false)
>    end
>  end
>
> end
>
>
>> Calling class
>
> # To change this template, choose Tools | Templates
> # and open the template in the editor.
>
> #require "rubygems"
> require "webrick"
> require "log4r"
> require "monitor"
> #require "XELogger"
> require "rexml/document"
>
> class XmlEngine < WEBrick::HTTPServlet::FileHandler
>
>  include MonitorMixin
>
>  # this is a BigNum
>  @@serialVersionUID = 1
>
> #  @xmlParser
> #  @htmlParsers
>  @hasXmlTemplate
>  @stcRead
>  @formatHashtable
>  @replaceHashtable

All of those instance variables are uninitialized. You just wrote
this:

   nil
   nil
   nil
   nil

So the first step would be to delete all of them.

> #  These loggers (xmlEngine and reloadXml) should be instantated before
> they can
> #  used.
>
>  @@log4rXmlEngine = XELogger.get['xmlEngine']
> #  @@log4rReloadXml = XELogger.get('reloadXml')
>
>  # Constructor
>  # ToDo: Assign this argument to the instance variable
> "connectionProvider"
>  def initialize(connectionProvider)
>    init
>  end
>
>  # Will configure log4r from the xml configure file passed
>  # The file object can be just the name of the file if the
>  # file is in the same folder, if otherwise file object
>  # should be a complete path to file's location.
>  # ToDo: Needs Tesing.
>  def self.configureLog4r(file)
>    if file !=nil
>      Configurator.load_xml_file(file)
>    else
>      Configurator.load_xml_file(log4r.xml)
>    end
>  end
>
>
> # Courtesy of:
> http://rubynugs.blogspot.com/2006/12/creating-java-like-main-method-in-ruby.html
>
> #  do
> #    if __FILE__ == $0 && ARGV.length < 1
> #      @i
> #      configureLog4r(nil)
> #      @strFile

Again, you're just stating values (nil or otherwise). If you're not
assigning to a variable or doing something with its value, there is
never any reason to type it.

I think you've got some ideas about declaring variables that perhaps
come from your work in another language but that are not relevant to
Ruby. The best thing would probably be to get hold of some learning
materials and find out what instance variables actually are, and how
they're used. That will give you a foothold as you work further on
your code.


David

-- 
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