Design Patterns
Short introduction of the most common design patterns in Python.
🎥 Video recording
Q:\08_DOCS\005_Oktatás_Kurzus\01_ECON\003PythonTipsAndTricks\VIDEO\2024_06_27_Design_Patterns.mp4
Factory
When the script has multiple functions with the same input but based on different inputs (variables) it is decided which one to call, create a different function that gets these variables and decides itself when to use which function
Exmaple
generator.py used in main.ipynb
Singleton
When the script has a class that is needed throughout the whole script, but don’t want to recreate it because of the lack of inputs or simply only one must exist.
Example
singleton.py used in main.ipynb
Bridge
When a class calls a function and that function should be changeable for example validating a simulation the input is always the same the simulation itself, but the function can be different
Example
bridge.py used in main.ipynb
MVC (Model-view-controller)
This is a structural design pattern that gives the programmer a system of files, where and how to put new code into the tool or where it can be found.
The rules are simple:
- Model holds the information about the used ‘classes’
- View should contain user interfaces, e.g.: TUI(Terminal-user-interface), GUI (Graphical-user-interface) webapps, …
- Controller stores the logic of the tool
Model communicates with outside tools like databases, jsons and classes are created from them View communicates with the Controller only, no exception, by default the View should never touch Models only through the Controller. This way, the View is doing only what is available in the Controller and no code duplication will happen. Controller communicates with the Model, it gets request from the View and sends the wanted information back.
Example
Plugin
This is also a structural design pattern that lets the code being expandable easily, meaning just copying a script with the wanted function names or having an additional config that tells the code what is the ‘entry point’
In the given example there is a JSON file that holds new scripts path and the tool looks for ‘ExtraTester’ class in these moduls (it can be expanded that not only ‘ExtraTester’ name is allowed) and runs the ‘test’ method inside that class also.