Template Method

• Intent: Define the skeleton of an algorithm in an operation, deferring some steps to subclasses.
• Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithm’s structure.

General Structure

Example

In my example the participants are represented as following:

• Abstract Class: EcommerceApp
• Concrete Class: Amazon, Ebay

Pros/Cons

Pros ❤️

• You can let clients override only certain parts of a large algorithm, making them less affected by changes that happen to other parts of the algorithm.
• You can pull the duplicate code into a superclass.

Cons 💔

• Some clients may be limited by the provided skeleton of an algorithm.
• You might violate the Liskov Substitution Principle by suppressing a default step implementation via a subclass.