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

The strategy pattern


A particular situation specific to behavioral patterns is when we need to change the way to solve a problem with another one. As we already learned in the first chapter, changing is bad, while extending is good. So, instead of replacing a portion of code with another one, we can encapsulate it in a class. Then we can create an abstraction of that class on which our code depends. From that point, our code becomes very flexible, as we can now use any class that implements the abstraction we just created.

Intent

The strategy pattern defines a family of algorithms, encapsulating each one, and makes them interchangeable.

Implementation

The structure of the strategy pattern is practically the same as the state pattern. However, the implementation and the intent are totally different:

The strategy pattern is quite simple:

  • Strategy: The abstraction of a specific strategy
  • ConcreteStrategy: The classes that implement the abstract strategy
  • Context: The class that runs a specific strategy...