Hello, In this short article I would like to talk about context managers. I personally consider that at the core they are just a form of decorators. If you don't know what a decorator is check the Decorator Pattern Wikipedia article. Decorators can be used to implement cross-cutting concerns. We have componentA and we need … Continue reading Context Managers and Cross Cutting concerns in Python
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Method Injection and Property Injection Design Patterns
Hello, In this article we're going to explore the Method Injection and Property Injection design patterns. To demonstrate the patterns I'm going to add a new interface named Encoder to the printer.py file and a concrete implementation for two encoders: Rot13Encoder and NullEncoder. class Encoder(metaclass=abc.ABCMeta): def encode(self, message: Message) -> Message: raise NotImplementedError("encode must be … Continue reading Method Injection and Property Injection Design Patterns
Constructor Injection and Null Object Design Patterns
The Constructor Injection design pattern is a pattern that helps you declare all the required dependencies of a class in it's constructor. This is useful because it helps you decouple the code, you can specify an interface instead of a concrete type, remember, program to an interface. Also, in the constructor it is easier to … Continue reading Constructor Injection and Null Object Design Patterns
Composition Root Pattern: How to Write Modular Software
The composition root is a design pattern which helps you structure a software application by implementing a class that builds all the other classes. In this example we will examine this pattern in Python. Here's the object graph of the classes that we're going to implement: I have designed a sample application that we're going … Continue reading Composition Root Pattern: How to Write Modular Software
