Lesser Known Design Patterns with Bevan Arps

Wellington Dot Net User Group Meeting

1. NULL Object Pattern - useful to declutter your code. Requires creation of a Null object in order to remove requirement to always check whether your object exists.


2. Command Pattern - Create function objects that interact with the object hierarchy.




• Effects: Localises code; Undo/Compensation; New function: New object.


• Considerations: Open-closed principle; # Classes; Likelihood of changes


3. Emancipated Objects Pattern - make objects responsibile for maintaining their own state.




• Effects: Read-only properties; Mutator methods; Validation


• Considerations: Applicability; Reusability; ORMs


4. Proposal Pattern - Complex Domain Factories. Explictly model the process that leads up to creation of the original object.


Effects: Natural Validation; Reduced Complexity; Increased Flexibility; Error Tolerant.


Considerations: Process Complexity; Process Duration.


5. State Pattern - Complex Domain Behaviour. Partially change the type of the object by swapping out behaviours based on state.
   
   
   
   • Effects: Switching removed; Grouped behaviour
   
   
   • Considerations: # Classes; Encapsulation; Complexity of Behaviour
   
   

Day 02 – Preferred programming language?

Visual Basic.NET (Visual Studio 2010)

Why?  Because historically, I progressed from:

• AppleSoft BASIC
• GW BASIC
• dBASE III Plus
• FoxPro
• Paradox
• Access
• VB 5.0
• VB 6.0
• VB.NET

In addition, Visual Basic.NET has the following advantages:

• VB not only stands for Visual Basic, but also Verbose.  It is a verbose language, which assist with self-documentation, as I don’t have to guess as much which } closes which statement.
• C#.NET coders are a dime a dozen.  You have to really love VB to go against the flow.  This makes you rare and more valuable.
• All the Java developers hate you.  I can live with that because I am anti-LAMP:

	Open Source	Microsoft
Operating System	Linux	Windows
Web Server	Apache	IIS
Database Server	MySQL	SQL Server
Language	PHP/Java	ASP.NET

This is day #1 of “30 Days of Geek” 

To find out more about what that means, read here: http://www.eguru.co.nz/2011/03/30-days-of-geek-challenge-starting-1st-april/

Day 01 – Why do you consider yourself a geek?

1. I’ve been coding since Form Four at Nelson College in 1984.
2. I am a Senior .NET Developer at Telecom New Zealand.
3. I am Web Master for Align Church.
4. I was Web Master for Grenada Village Residents Association.
5. I was Web Master for Wellington Home Education Network.
6. I am a Microsoft Certified Trainer.
7. I am a Microsoft Certified Professional Developer (.NET Framework 2.0 – Web Developer).
8. I am a Microsoft Certified IT Professional (SQL Server 2005)
9. People ask me to fix their computers at parties.
10. I carry an LG (Android) Smartphone.
11. I am known as “Mr. VB” at Dot Net User Group meetings.

That’ll do for now.