Book Image

Spring 5.0 Cookbook

By : Sherwin John C. Tragura
Book Image

Spring 5.0 Cookbook

By: Sherwin John C. Tragura

Overview of this book

The Spring framework has been the go-to framework for Java developers for quite some time. It enhances modularity, provides more readable code, and enables the developer to focus on developing the application while the underlying framework takes care of transaction APIs, remote APIs, JMX APIs, and JMS APIs. The upcoming version of the Spring Framework has a lot to offer, above and beyond the platform upgrade to Java 9, and this book will show you all you need to know to overcome common to advanced problems you might face. Each recipe will showcase some old and new issues and solutions, right from configuring Spring 5.0 container to testing its components. Most importantly, the book will highlight concurrent processes, asynchronous MVC and reactive programming using Reactor Core APIs. Aside from the core components, this book will also include integration of third-party technologies that are mostly needed in building enterprise applications. By the end of the book, the reader will not only be well versed with the essential concepts of Spring, but will also have mastered its latest features in a solution-oriented manner.
Table of Contents (20 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Validating parameters and arguments


Custom annotations can also be aspects to validate if arguments passed to @Service methods are appropriate or not. The following recipe will use AOP paradigms to intercept parameter passing.

Getting started

Open ch05 and add an @Aspect that will utilize custom annotation to validate the employee ID parameter of the readEmployee() service method of TransactionTemplate.

How to do it...

Let us now perform validation on method arguments by doing the following steps:

  1. This recipe will start with the creation of a class-level annotation which is not a transactional type, just like in the previous recipe. Using again the Reflection API, implement an annotation that will be used by an @Aspect to intercept parameter passing.
@Retention(RetentionPolicy.RUNTIME) 
@Target(ElementType.PARAMETER) 
public @interface NegativeArgs { } 
  1. Since a valid employee ID is a positive number, create an aspect that will validate if the empId argument passed onto readEmployee() of EmployeeServiceImpl...