Abstract Classes are a good fit if you want to provide implementation details to your children but don’t want to allow an instance of your class to be directly instantiated (which allows you to partially define a class).
Abstract methods are useful in the same way that defining methods in an interface is useful. It’s a way for the designer of the Abstract class to say “Any child of mine MUST implement this method”.
Not only can you define a template for children, but Abstract Classes offer the added benefit of letting you define the functionality that your child classes can utilize later.
When to Use Abstract Class?
Abstract classes are used in object-oriented programming to provide a common base or blueprint for derived classes. They are designed to be inherited from and serve as a template for creating concrete classes. Here are some situations when you might want to use an abstract class:
- Creating a common interface: If you have a group of related classes that share common methods or properties, you can define an abstract class to provide a common interface. The abstract class can declare abstract methods (methods without an implementation) that derived classes must implement. This allows you to enforce a certain structure or behavior across multiple classes.
- Implementing inheritance: Abstract classes are useful when you want to create a hierarchy of classes, with a base class defining common functionality and derived classes extending or specializing that functionality. The abstract class provides a foundation for the derived classes to build upon. It can contain both abstract and non-abstract methods, allowing derived classes to inherit and override methods as needed.
- Enforcing contracts: Abstract classes can be used to define contracts or rules that derived classes must follow. By defining abstract methods and properties, an abstract class can specify a set of requirements that any derived class must meet. This helps to enforce consistency and ensures that all derived classes adhere to a specific contract.
- Providing default implementations: Abstract classes can contain both abstract and non-abstract methods. Non-abstract methods in the abstract class can provide default implementations that can be inherited by derived classes. Derived classes can choose to override these methods if they need different behavior or can rely on the default implementation provided by the abstract class.
- Preventing direct instantiation: Abstract classes cannot be instantiated directly. They are meant to be inherited from and serve as a base for creating concrete classes. This can be useful when you want to prevent direct instantiation of a class and force users to create instances of derived classes instead.
Overall, abstract classes are useful when you want to define a common interface, establish a class hierarchy, enforce contracts, provide default implementations, or prevent direct instantiation. They promote code reusability, and maintainability, and allow for future extensibility.
