Large Class#
Classes never start out big. They start out small and grow over time and get bloated. This is a problem because it makes the class harder to understand and harder to change. It also makes it harder to reuse the class in other contexts.
We programmers are lazy and tend to find it easier to add code to an existing class than to create a new class. It is very understandable but it is not a good practice.
Signs and Symptoms of a large class#
High Line Count: The class contains a large number of lines of code, making it challenging to understand and maintain. Long classes tend to become unwieldy and harder to navigate.
Excessive Responsibilities: The class is responsible for handling too many tasks or functionalities. It violates the Single Responsibility Principle (SRP) and becomes a “god object” that knows too much and does too much.
Complexity: The class may have multiple nested conditional statements, loops, and intricate logic, making it hard to follow the control flow and leading to potential bugs.
Code Duplication: Due to its extensive functionality, the class may be duplicated or used in multiple places, leading to redundancy and maintenance issues.
Poor Maintainability: Making changes to the class becomes risky and time-consuming since it impacts many parts of the system.
Low Cohesion: The class lacks clear, well-defined boundaries for its responsibilities, resulting in a lack of cohesion within the class.
Decreased Understandability: As the class grows larger, it becomes harder for developers to comprehend its purpose and behavior, reducing code readability.
Testing Challenges: Writing comprehensive unit tests for such a large class becomes complicated, leading to inadequate test coverage and potential regressions.
High Coupling: The large class might be tightly coupled (coupling) with other classes, making it difficult to reuse and maintain independently.
Code Smells: The class may exhibit other code smells, such as Long Method, excessive parameters, or Feature envy, further exacerbating the problem.
Slow Compilation: Due to the large class size, recompilation of the codebase can become slow, affecting development productivity, but this may a bit of a stretch since compilation time is usually not a problem anymore.
12 Testing Challenges: Writing comprehensive unit tests for the large class becomes difficult, leading to inadequate test coverage and potential regressions.
Solutions#
Addressing the “Large Class” refactoring problem typically involves breaking down the class into smaller, more focused classes with clear responsibilities. This restructuring enhances code organization, improves maintainability, and reduces complexity, making the software more robust and easier to work with in the long run.
Extract Class
Extract Subclass
Extract Interface