Book Image

Developing Middleware in Java EE 8

Book Image

Developing Middleware in Java EE 8

Overview of this book

Middleware is the infrastructure in software based applications that enables businesses to solve problems, operate more efficiently, and make money. As the use of middleware extends beyond a single application, the importance of having it written by experts increases substantially. This book will help you become an expert in developing middleware for a variety of applications. The book starts off by exploring the latest Java EE 8 APIs with newer features and managing dependencies with CDI 2.0. You will learn to implement object-to-relational mapping using JPA 2.1 and validate data using bean validation. You will also work with different types of EJB to develop business logic, and with design RESTful APIs by utilizing different HTTP methods and activating JAX-RS features in enterprise applications. You will learn to secure your middleware with Java Security 1.0 and implement various authentication techniques, such as OAuth authentication. In the concluding chapters, you will use various test technologies, such as JUnit and Mockito, to test applications, and Docker to deploy your enterprise applications. By the end of the book, you will be proficient in developing robust, effective, and distributed middleware for your business.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Graph validation


The bean validation API also supports graph validation, which means that if some object is referencing another one, you can define a constraint that your embedded object should also be validated from the owner's one context, according to the constraints defined in the embedded object.

Let's try this with an example; we will define a Producer class with a constraint on the name attribute as follows:

public class Producer { 
 
    @NotNull 
    private String name; 
 
    // setters and getters here 
 
} 

Then, we will modify our Movie object so it references an instance of the Producer object, as follows:

public class Movie { 
 
    @NotNull 
    private String title; 
    @Valid 
    private Producer producer; 
 
    public Movie() { 
    } 
    // setters and getters here 
} 

Note the @Valid attribute; it tells the bean validator that when validating the Movie object, the Producer object should also be validated.

Now, let's try to create a movie and producer objects with null...