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Object-Oriented Thinking
Use Polymorphism to Simplify Code
Issue: 2.2 (October/November 2003)
Author: Charles Yeomans
Author Bio: Charles Yeomans is a software developer in Lexington, Kentucky
Article Description: No description available.
Article Length (in bytes): 4,807
Starting Page Number: 36
RBD Number: 2216
Resource File(s): None
Related Web Link(s):
http://www.refactoring.com/
Known Limitations: None
Excerpt of article text...
You're writing a widget server, and you'll want to implement logging. You'll want to offer several logging levels; let's say, Error, Warning, and Debug. You'll want to offer various output possibilities -- Console, log file, or no output for each logging level. Let's take a hypothetical look at how you might do that.
We'll start with a module Logger; I suggest a module because I expect that we'll want one instance only, and we'll want it always available.
Sub LogErrorMessage(message as String)
dim msgDate as Date
dim logMsg as String
msgDate = new Date
logMsg = msgDate.ShortDate + " " + msgDate.ShortTime + " " + "Error: " + message
If LogErrorsToConsole then
TellConsole logMsg
ElseIf LogErrorsToFile then
AppendToFile logMsg
Else
//don't log these messages
End if
End Sub
TellConsole and AppendToFile are protected subroutines that do what their names suggest. LogErrorsToConsole and LogErrorsToFile are Boolean constants set in a preferences window somewhere.
...End of Excerpt. Please purchase the magazine to read the full article.
Article copyrighted by REALbasic Developer magazine. All rights reserved.
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