Introducing Spring Framework

Chapter 2 ■ Working with Classes and Dependencies
Figure 2-3. Dependency Injection
Figure 2-3 shows how any implementation of your SearchEngine interface can be injected. Perhaps you are
searching through a database or maybe you’re using a file to retrieve some information. The Spring Framework also
provides several features such as the following:
• Dependency injection
• Aspect-oriented programming
• Data access
• Transaction management
• Web flow and MVC
• Social frameworks
• Messaging
• Remoting
• Testing
• and more . . .
Right now you do not need to worry about each of these features. Over the course of the book, you are going to
see each one of them in action through your Spring application, My Documents.
I was talking about how the Spring Framework creates instances of your declared beans in the XML file
(Listing 2-7), and how these are ready when you need them or are injected when required. But how does the Spring
Framework know what classes need to be injected? The Spring Framework has several mechanisms to accomplish
this: by name or by type. The injection can be either using Setters methods or constructors. But you are going to see
this in detail in the following chapters. For now, let’s take a look at Figure 2-4 for an overview of the Spring container.
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