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 EJB method


In our implementation example, we will use the same scenario as in the example of an Event in CDI. 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 type of extension received, the file received will be saved on the filesystem at its respective directory. To develop this example, we will use the following classes:

  • FileUploadResource: This is a class that represents the resource to receive all request to upload, and calls the respective EJB according to the file extension.
  • JpgHandler: This is an EJB with an asynchronous method to treat the process save of a JPG file on disk.
  • PdfHandler: This is an EJB with an asynchronous method to treat the process save of a PDF file on disk.
  • ZipHandler: This is an EJB with an asynchronous method to treat the process save of a ZIP file on disk.
  • FileSystemUtils: This is a utility class intended to handle issues with the...