From: David Alan Black <dblack@...>
Date: 2004-05-25T05:53:45+09:00
Subject: Re: Design Question

Hello --

"Zach Dennis" <zdennis@mktec.com> writes:

> I am having a small dillema. In a program I and a friend are writing I am
> proposing to have a Singleton Error/Status object that is updated with
> error/status information. For example (this code is nont tested and it is
> just a conceptual look):
> 
> 
> class StatusSingleton
> 	def setStatus( returnCode , message , obj=nil )
> 		@returnCode = returnCode
> 		@message = message
> 		@obj = obj
> 	end
> 
> 	def getLastReturnCode
> 		return @returnCode
> 	end

A quick hint: rather than use methods that start with "get" and "set"
and just return instance variables, use the attr_* family of methods
instead.

> 
> 	def getLastMessage
> 		return @message
> 	end
> end
> 
> class MyObj
> 	def setTrue
> 		#A Big Error Occurs
> 		StatusSingleton.setStatus( "0x0080" , "Could not set true" );
> 	end
> end
> 
> m = MyObj.new();
> if( !m.setTrue() ) then
> 	MyTkTextFieldWidget.setText( StatusSingleton.getLastMessage() )
> end
> 
> 
> 
> Is my StatusSinglton overkill? I am trying to consolidate error information
> into one class. What do you think?

Another idea might be just to create your own Exception class:

  class SomeException < Exception; end

and then raise and rescue accordingly:

  begin
    m = MyObject.new
    # do stuff that raises a SomeException on error
  rescue SomeException => e
    MyTkTextFieldWidget.set_text(e.message)
  end

But there may be something that this doesn't give you that I'm not
taking into account.


David

-- 
David A. Black
dblack@wobblini.net