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 the service-activator pattern


We are now going to show code examples of the three solutions offered by the Java EE platform.

Implementing sending and receiving messages with JMS

The following is an example of a JMS message sender. This is a CDI bean that is responsible for sending messages:

public class MessageSender {
   @Inject
   @JMSConnectionFactory("jms/connectionFactory")
   JMSContext context;

   @Resource(mappedName = "jms/myQueue")
   Destination queue;

   public void sendSomeMessage (String message) {
      context.createProducer().send(queue, message);
   }
}

The @JMSConnectionFactory annotation indicates which ConnectionFactory should be used to create the JMSContext. The following code block shows an MDB that receives the message generated by the producer described earlier:

@MessageDriven(
 activationConfig = { @ActivationConfigProperty(
 propertyName = "destinationType", propertyValue = "javax.jms.Queue")
 })
public class EmailService implements MessageListener ...