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 an asynchronous REST service


As an example of implementing an asynchronous REST service, we will use the same scenario used in the example of the event in the CDI and the asynchronous EJB method. Here, we will create an application that makes it possible to upload three types (or extensions) of files—ZIP, JPG, and PDF extensions. Depending on the extension received, we want the file received to be kept in its respective directory on the filesystem. To develop this example, we have the following classes:

  • FileUploadResource: This is a class that represents the resource that works with asynchronous processes to receive all requests to upload, and calls the respective EJB according to the file extension.
  • JpgHandler: This is an EJB with an available method for saving a JPG file on a disk.
  • PdfHandler: This is an EJB with an available method for saving a PDF file on a disk.
  • ZipHandler: This is an EJB with an available method for saving a ZIP file on a disk.
  • FileSystemUtils: This is a utility...