The Template Method Pattern is a design pattern in software development that falls under the category of behavioral patterns. It allows defining the basic outline of an algorithm in an abstract class while letting the details of individual steps be implemented in derived classes.
The Template Method Pattern consists of the following main components:
AbstractClass: The abstract class defines a template for the algorithm and contains one or more abstract methods that must be implemented by the derived classes. These abstract methods represent the specific steps of the algorithm that can vary in the derived classes. The abstract class also includes a template method that defines the basic flow of the algorithm and accesses the abstract methods to complete the algorithm.
ConcreteClass: These are the concrete implementations of the abstract class. Each concrete class implements the abstract methods of the abstract class to specify the specific details of the algorithm. The concrete class may also contain additional methods or properties that are specific to the algorithm.
The flow works as follows: The abstract class contains the template method that defines the algorithm. This template method internally calls the abstract methods to execute the specific steps of the algorithm. The abstract methods are implemented by the concrete classes that inherit from the abstract class. Each concrete class provides its own implementation for the abstract methods, thus customizing the algorithm accordingly.
The Template Method Pattern promotes code reuse since the basic algorithm is defined in the abstract class and does not need to be duplicated in each concrete class. It also allows for the variation of individual steps of an algorithm by enabling the concrete classes to provide specific implementations for the abstract methods. This keeps the algorithm flexible and extensible without altering the overall flow.
Erlang
