TobiW's Design Study
Contents |
Overview
I decided to do the design study on a program I wrote back in Germany before I came here. I wrote it to have a single interface to the many meteorological sites I use to predict and learn something about the weather (mainly for my hobby flying sailplanes). It is quite useable but far from being finished. Technical details: it is written in Python using wxPython for the GUI, and has approx. 2500 lines of code (counted with CLOC).
The project is hosted on sourceforge: [1]
Here's the description I put up on Sourceforge: FreeMet is a meteorological program which provides weather maps, radar movies and forecasts in one GUI. New function can be added easily by writing new plugins which download, parse or process existing data available on the internet.
Design Study Goals
After having done a thorough design study I hope to
- have good documentation to make it easier for myself and others to start working on the program (again),
- discover major and minor design flaws,
- learn all those design patterns and code smells by looking at my code and trying to find them.
Python
Here, I want to list some Python-specific stuff:
- A list can store arbitrary values, a set automatically removes duplicates.
- A dictionary in Python is a Map/HashMap which maps string keys to arbitrary values.
- __init__() is the class's contructor and __del__() its destructor.
Current Design
- I included parts of wxPython to illustrate dependencies.
- The service class implements a plugin architecture
OO Principles and Patterns
Design Flaws
Even before doing a thorough analysis I've discovered several flaws in my design that will need some fixing:
- I usually write my programs around one central class which handles most of the logic. This could conflict with avoid god classes or the large class smell.
- After learning a lot about the Getter and setter policy, I'm sure I'll be able to eliminate many accessor methods.
- Probably because I was too lazy I didn't make all attributes private (Information hiding).
- Similar to the previous point, there are too many public methods that are only used internally.
Possible Improvements
- Apply Singleton pattern to Frame and SplashScreen.
