Book Image

Design Patterns and Best Practices in Java

By : Kamalmeet Singh, Adrian Ianculescu, Lucian-Paul Torje
Book Image

Design Patterns and Best Practices in Java

By: Kamalmeet Singh, Adrian Ianculescu, Lucian-Paul Torje

Overview of this book

Having a knowledge of design patterns enables you, as a developer, to improve your code base, promote code reuse, and make the architecture more robust. As languages evolve, new features take time to fully understand before they are adopted en masse. The mission of this book is to ease the adoption of the latest trends and provide good practices for programmers. We focus on showing you the practical aspects of smarter coding in Java. We'll start off by going over object-oriented (OOP) and functional programming (FP) paradigms, moving on to describe the most frequently used design patterns in their classical format and explain how Java’s functional programming features are changing them. You will learn to enhance implementations by mixing OOP and FP, and finally get to know about the reactive programming model, where FP and OOP are used in conjunction with a view to writing better code. Gradually, the book will show you the latest trends in architecture, moving from MVC to microservices and serverless architecture. We will finish off by highlighting the new Java features and best practices. By the end of the book, you will be able to efficiently address common problems faced while developing applications and be comfortable working on scalable and maintainable projects of any size.
Table of Contents (15 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Façade pattern


Many complex systems are reducible to just a couple of their use cases, exposed by the subsystems. By doing so, the client code does not need to know about the internals of the subsystem. In other words, the client code is decoupled from it and it takes less time for the developer to use it. This is known as a façade pattern, where the façade object is responsible for exposing all the subsystem's functionality. This concept resembles encapsulation, where we hide the internals of an object. With façade, we hide the internals of a subsystem and expose just the essentials. The consequence is that the user is limited to the functionality exposed by the façade, and is not able to use/reuse specific functionality from the subsystem.

The façade pattern needs to adopt the internal subsystem interface (many interfaces) to the client code interface (one interface). It does this by creating a new interface, while the adapter pattern adapts to and from existing interfaces (sometimes more...