Null Pattern Last time I blogged about “Learn the Null Pattern“, but I forgot to mention one thing about the Null Pattern. That is you have to be mindful of it. For example
|
1 2 3 4 5 6 |
foreach(var id in IDList) { var employee = db.GetEmployee(id); salary = db.CalculateSalary(id); employee.Pay(salary); } |
The code looks okay but what if the GetEmployee method actually returns a NullEmployee? Well that would still be okay, since […]
Today, I thought I would mention the Null Object design pattern, its an object that provides intelligent do nothing behavior, hiding the details from its collaborators. So what does this mean??? Before I tell you what it means, lets see an example of how often you might be seeing code that is checking for null. […]
As promised here is the version of observer pattern with Event & Delegate. Personally I am not a big fan of this solution, although it does remove quite a bit of code and show how to use a push model with the observer pattern. Next time around I will show a more elegant solution by […]
Learn the Observer Pattern: I am starting to write a series of blog post which would be named “Learn {tagline}…..” In these series I would post things about design pattern, programming methodologies, skills etc etc For today, I will start with my favorite Design Pattern. The Observer Pattern. I would first state out what the […]
This is part 2 of Extract and Override refactoring technique. You can find part 1 in my previous post. I am going to show another technique by using Factory Method to break dependency in your code. *WARNING* *WARNING* Before I begin I would like to say all these techniques are not the best design but […]
The Law of Demeter (LoD), or Principle of Least Knowledge, is a design guideline for developing software, particularly object-oriented programs. (wikipedia) While everyday working on code that was written by lazy coders or junior coders I see a lot of violation of this law. I think every programmer should know the Law of Demeter by […]
