Introducing Spring Framework

Chapter 4 ■ Using Beans Scopes
Table 4-1. Bean Scopes
Scope
singleton
prototype
request
session
globalSession
Definition
The Spring container returns a single instance. This is the default value.
The Spring container returns a new instance every time it is requested.
The Spring container returns a new instance on each HTTP request; this is used in a web context.
The Spring container returns a new instance on each HTTP session; this is used in a web context.
The Spring container returns a single instance per global HTTP session; this is used in a
web context.
In the next sections, you will see different ways to use these bean scopes. You need to be very careful to choose
the right scope because that could impact your application.
Using the @Scope Annotation
You need to remember that the Spring Framework has different ways to configure its container: XML, annotations,
Java configuration classes, and the new GroovyBeanDefinitionReader. If you are going to use either the annotated
beans or the Java bean configuration to get the instance of your beans, then it is necessary to use the @Scope
annotation. Listing 4-4 shows the modified code.
Listing 4-4. AnnotatedSearchEngine.java
package com.apress.isf.spring.annotated.service;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;
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;
import com.apress.isf.spring.service.ServiceSearchEngine;
@Service("engine")
@Scope("prototype")
public class AnnotatedSearchEngine implements SearchEngine {
private static final Logger log =
LoggerFactory.getLogger(ServiceSearchEngine.class);
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