The template method pattern
The template method pattern, as the name suggests, provides a template for code, which can be filled in by developers implementing different functionalities. The easiest way to understand this is to think in terms of HTML templates. Most of the websites you visit follow some kind of template. For example, there is usually a header, a footer, and a sidebar, and in between, we have the core content. That means the template is defined with a header, footer, and sidebars, and every content writer can use this template to add their content.
Intent
The idea of using the template method pattern is to avoid writing duplicate code so that developers can focus on core logic.
Implementation
The template method pattern is best implemented using an abstract class. The areas for which we know about the implementation will be provided; the default implementation and the areas that are to be kept open for implementation are marked abstract.
For example, think of a database fetch query...
