How can you reduce the coupling between classes in your OOP code?

2 Use dependency injection

Another way to reduce coupling is to use dependency injection, which is a design pattern that allows a class to receive its dependencies from an external source, instead of creating them internally. This way, you can avoid hard-coding the dependencies in the class, and make them more configurable and testable. For example, instead of having a class that creates a new database connection every time it needs one, you can have it receive a database connection object from a dependency injection framework or a factory method. This way, you can control the scope and lifetime of the database connection, and mock it for testing purposes.

3 Use composition over inheritance

A third way to reduce coupling is to use composition over inheritance, which is a principle that favors creating classes that contain other classes as attributes, instead of extending them as subclasses. This way, you can avoid inheriting unnecessary methods and fields from the parent class, and make the relationship between classes more explicit and flexible. For example, instead of having a class that extends a generic animal class, you can have it contain an animal object as an attribute, and delegate some methods to it. This way, you can change the behavior and characteristics of the class without affecting the animal class.

4 Use the principle of least knowledge

A fourth way to reduce coupling is to use the principle of least knowledge, which is a guideline that states that a class should only interact with a few other classes that are closely related to it, and avoid exposing its internal details to others. This way, you can limit the scope and impact of changes in the class, and make the code more cohesive and encapsulated. For example, instead of having a class that accesses the fields and methods of another class directly, you can have it use a public method that encapsulates the logic and data of the other class. This way, you can hide the implementation details of the other class, and reduce the coupling between them.

5 Use design patterns

A fifth way to reduce coupling is to use design patterns, which are proven solutions to common design problems in OOP. Design patterns can help you structure your code in a way that promotes low coupling and high cohesion, by providing clear roles and responsibilities for each class, and defining the communication and collaboration between them. For example, some design patterns that can help you reduce coupling are the observer pattern, which allows a class to notify other classes of changes without knowing them, the mediator pattern, which allows a class to interact with other classes through a central class, and the facade pattern, which allows a class to access a complex system through a simplified interface.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?