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 memento pattern


Encapsulation is one of the fundamental principles of object-oriented design. We also know that each class should have a single responsibility. As we add functionality to our object, we might realize that we need to save its internal state to be able to restore it at a later stage. If we implement such functionality directly in the class, the class might become too complex and we might end up breaking the single responsibility principle. At the same time, encapsulation prevents us having direct access to the internal state of the object we need to memorize.

Intent

The memento pattern is used to save the internal state of an object without breaking its encapsulation, and to restore its state at a later stage.

Implementation

The memento pattern relies on three classes: Originator, Memento, and Caretaker, as shown in the following class diagram:

The memento pattern relies on the following classes:

  • Originator: The originator is the object for which we need to memorize the state...