Book Image

Java EE 8 Design Patterns and Best Practices

By : Rhuan Rocha, Joao Carlos Purificação
Book Image

Java EE 8 Design Patterns and Best Practices

By: Rhuan Rocha, Joao Carlos Purificação

Overview of this book

Patterns are essential design tools for Java developers. Java EE Design Patterns and Best Practices helps developers attain better code quality and progress to higher levels of architectural creativity by examining the purpose of each available pattern and demonstrating its implementation with various code examples. This book will take you through a number of patterns and their Java EE-specific implementations. In the beginning, you will learn the foundation for, and importance of, design patterns in Java EE, and then will move on to implement various patterns on the presentation tier, business tier, and integration tier. Further, you will explore the patterns involved in Aspect-Oriented Programming (AOP) and take a closer look at reactive patterns. Moving on, you will be introduced to modern architectural patterns involved in composing microservices and cloud-native applications. You will get acquainted with security patterns and operational patterns involved in scaling and monitoring, along with some patterns involved in deployment. By the end of the book, you will be able to efficiently address common problems faced when developing applications and will be comfortable working on scalable and maintainable projects of any size.
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
5
Aspect-Oriented Programming and Design Patterns
Index

Implementing microservices


The idea behind the implementation of microservices in our example is to implement a microservice that provides the bank data for a client to generate a payment slip. The data returned will be the barcode of the payment slip.

The bank provides two SOAP web services, one to register the payment slip with the bank and one to provide the data for generating the payment slip that was already registered. As a result, we will make two microservices, one for registering the payment slip data and another for the query of the payment slip that was already registered. Each of these microservices will call the related web service. Next, we will construct a third, more complex microservice that will add two calls: a call to the registration microservice and another to retrieve what was registered. Let's look at the following diagram:

We could, in fact, make a microservice chain here; however, we opted for the aggregator pattern because we assume that multiple payment slips may...