Introducing Spring Framework

Chapter 8
Give Advice to Your Spring
Application
In this chapter, you will review part of your logic and refactor some of the classes to make the application more
functional. In the previous chapters, I introduced some Spring concepts for your application, like dependency
injection, how to use collections, how to load external resources, and how to use Profiles and testing. You did a little
testing with them, but you need to actually see something real, right? So in this chapter you are going to give advice to
your My Documents app.
Advice to My Documents
So what is this “advice” thingy anyway? Remember your SearchEngineService.java class from previous chapters?
You just added logs everywhere in order to find out what was going on in every method (if you were passing the
correct parameter or not, and if the result was what you expected). Now imagine for a moment that this class needs
some new logic added to it, something like a security checkpoint for every method written where only users with
a username and password are allowed to execute certain logic, or maybe audit checks for some methods, or some
particular business logic you have, like having a counter to see how many times a user uses a particular method call.
This new logic would become a nightmare—too much code to add for something that should be simple! You would
end up having too many calls to do security or audit checks, and the same code would be all over the place. Let’s look
at Listing 8-1, which is your SearchEngineService class.
Listing 8-1. SearchEngineService.java
package com.apress.isf.spring.service;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.apress.isf.java.model.Document;
import com.apress.isf.java.model.Type;
import com.apress.isf.java.service.SearchEngine;
import com.apress.isf.spring.data.DocumentDAO;
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