Chris Schaefer

Introducing Spring AOP

Besides Dependency Injection (DI), another core feature that the Spring Framework brings to the developer community is Aspect-Oriented Programming (AOP). Although it used to be difficult to learn, understand, and implement, thanks to Spring’s intensive use of AOP within the framework and a simplified AOP programming model that Spring provides, AOP has become a technique that developers use on day-to-day development, especially when developing Spring-based applications. AOP is often referred to as a tool for implementing crosscutting concerns. When you “cut through” the unfamiliar terminology, you use AOP for modularizing individual pieces of logic, known as concerns, and you apply these concerns to many parts of an application. Logging and security are typical examples of crosscutting concerns that are present in many applications. Consider an application that logs the start and end of every method for debugging purposes. You will probably refactor the logging code into a special class, but you still have to call methods on that class twice per method in your application in order to perform the logging. Using AOP, you can simply specify that you want the methods on your logging class to be invoked before and after each method call in your application.

Spring Configuration in Detail and Spring Boot

In the previous chapter, we presented a detailed look at the concept of inversion of control (IoC) and how it fits into the Spring Framework. However, we have really only scratched the surface of what Spring Core can do. Spring provides a wide array of services that supplement and extend its basic IoC capabilities.

Spring Projects: Batch, Integration, XD, and Boot

This chapter presents a high-level overview of a few projects that are part of the Spring portfolio, notably Spring Batch, Integration, XD, and a few notable features added in Spring Framework version 5. This chapter is not intended to cover each project in detail but to provide just enough information and a sample to get you started. The Spring portfolio contains many more projects than the ones discussed in this chapter, but we feel the ones presented here are widely used, and some are new and upcoming projects. You can view the full list of Spring projects at http://spring.io/projects . This chapter covers the following topics

Task Scheduling in Spring

Task scheduling is a common feature in enterprise applications. Task scheduling is composed mainly of three parts: the task (which is the piece of business logic needed to run at a specific time or on a regular basis), the trigger (which specifies the condition under which the task should be executed), and the scheduler (which executes the task based on the information from the trigger).

Spring Configuration in Detail

In the previous chapter, we presented a detailed look at the concept of Inversion of Control (IoC) and how it fits into the Spring Framework. However, we have really only scratched the surface of what the Spring core can do. Spring provides a wide array of services that supplement and extend its basic IoC capabilities. In this chapter, you are going to explore these in detail. Specifically, you will be looking at the following:

Web Applications with Spring

In an enterprise application, the presentation layer is a critical layer that significantly affects the acceptance level of the application by the users. The presentation layer is the front door into your application. It lets the users perform business functions provided by the application, as well as provides a visual view of the information that is being maintained by the application. How the user interface performs greatly contributes to the success of the application.

Introducing IoC and DI in Spring

In Chapter 1, we covered the basic principles of Inversion of Control (IoC) and Dependency Injection (DI). Practically, DI is a specialized form of IoC, although you will often find that the two terms are used interchangeably. In this chapter, we take a much more detailed look at IoC and DI, formalizing the relationship between the two concepts and looking in great detail at how Spring fits into the picture.

Using Spring Remoting

An enterprise application typically needs to communicate with other applications. Take, for example, for a company selling products; when a customer places an order, an order-processing system processes the order and generates a transaction. During the order processing, an inquiry is made to the inventory system to check whether the product is available in stock. Upon order confirmation, a notification is sent to the fulfillment system to deliver the product to the customer. Finally, the information is sent to the accounting system; an invoice is generated and the payment is processed.

Spring Application Monitoring

A typical JEE application contains a number of layers and components, such as the presentation layer, service layer, persistence layer, backend data source, and so on. During the development stage or after the application had been deployed to the quality assurance (QA) or production environment, we want to ensure that the application is in a healthy state without any potential problems or bottlenecks.