Onion architecture

-
Jeff seems to have put it very well in his blog. Much better than I did myself back in December 2006 when I blogged about my "Onion" idea.

My mistakes were
01: I was missing a domain services layer.
02: I tried to explain it using a specific example (wizard app with a "process stack" aka "task stack"), and later decided I didn't like the example :-)
03: When I drew my diagrams I showed them as a typical stacked diagram, because my graphics skills are crap :-)

Here's my badly put idea of onion layered applications:
http://mrpmorris.blogspot.com/2006/12/net-onion-part-1.html

Here's Jeffrey's
http://jeffreypalermo.com/blog/the-onion-architecture-part-1/

Well done Jeff, very nicely put!

Comments

Post a Comment

Popular posts from this blog

Connascence

-
I’ve just finished reading What every programmer should know about object oriented design . The first couple of sections are a bit useless really, but the 3rd section is very good. I particularly liked the section on the difference types of connascence in software. There’s some basic information about it here if you fancy a brief overview of what it is about. It’s a really good book, I recommend you read it! Should only take a day if you only read the 3rd section.
Read more

Convert absolute path to relative path

-
Today I needed to convert an absolute path to a relative path based on a specified base path. E.g. c:\a\b\c -> c:\a\b\c\d\file.txt = d\file.txt c:\a\b\c -> c:\a\file.txt = ..\..\file.txt c:\a\b\c -> c:\a\x\file.txt = ..\..\x\file.txt I am surprised there is nothing in the .NET framework so I had a hunt around and converted the code from the following URL ( http://www.vergentsoftware.com/blogs/ckinsman/default.aspx?date=2006-08-07 ) into C#.... private string RelativePath(string absolutePath, string relativeTo) { string[] absoluteDirectories = absolutePath.Split('\\'); string[] relativeDirectories = relativeTo.Split('\\'); //Get the shortest of the two paths int length = absoluteDirectories.Length < relativeDirectories.Length ? absoluteDirectories.Length : relativeDirectories.Length; //Use to determine where in the loop we exited int lastCommonRoot = -1; int i
Read more

Printing bitmaps using CPCL

-
I've had no end of grief trying to print a PCX to a Zebra Printer using the CPCL printer language. Silly me, didn't notice the EG command (expanded graphics) so there was no need to convert my BMP to a PCX and then struggle with binary data. I still had a bit of grief working out how to print using the EG command because the documentation is quite frankly crap. The expected command format is EG {WidthInBytes} {HeightInPixels} {XPos} {YPos} {Data}\r\n The printer expects a 1 bit pixel matrix. So if pixel(0, 0) is set you will set "80" in the data. If pixel(0, 0) is set and pixel (7, 0) is also set you would sent "81". Basically what you need to do is to read each set of 8 horizontal pixels and then use bit operations to create a byte value 0..255, and then output this as hex 00..FF. Here's the routine :-) public void DrawBitmap(Bitmap bmp, int xPosition, int yPosition) { if (bmp == null) throw new ArgumentNullException("bmp");
Read more