Prototype Scoped Component

[Vasil'ev Nickolay]

Is is possible to create prototype scoped component in JIRA plugin? My intention is to create a different object on each dependency injection. Spring prototype scope seems to be intended for that reason. But annotation

@Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE, proxyMode = ScopedProxyMode.TARGET_CLASS)

doesn't seems to have any effect on a component, which is effectively stays "singleton" (checked at runtime through ApplicationContext.isPrototype(String name)). 

[Vasil'ev Nickolay · Accepted solution]

Well, I've come with next solution. Let's say, we want to define class com.example.proto.MyProtoBean as prototype bean. 
1. We need to explicitly define Spring Context within "plugin-context.xml" file. In conjunction with atlassian-spring-scanner-2 settings it should look something like this:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:atlassian-scanner="http://www.atlassian.com/schema/atlassian-scanner/2"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
        http://www.atlassian.com/schema/atlassian-scanner/2
        http://www.atlassian.com/schema/atlassian-scanner/2/atlassian-scanner.xsd">
    <atlassian-scanner:scan-indexes/>

    <context:annotation-config/>
    <context:component-scan base-package="com.example.proto"/>

</beans>

2. Important detail is to exclude given package from atlassian-spring-scanner plugin index: otherwise, it's going to be parsed as singleton bean. You can exclude package with <inclueExclude> in plugin configuration:

<plugin>
    <groupId>com.atlassian.plugin</groupId>
    <artifactId>atlassian-spring-scanner-maven-plugin</artifactId>
    <version>${atlassian.spring.scanner.version}</version>
    <executions>
        <execution>
            <goals>
                <goal>atlassian-spring-scanner</goal>
            </goals>
            <phase>process-classes</phase>
        </execution>
    </executions>
    <configuration>
        <includeExclude>
             -com.example.proto.*
        </includeExclude>
        <!-- 
             You can also add verbose output to make sure that package is not parsed at all
             <verbose>true</verbose> 
        -->
    </configuration>
</plugin>

3. For prototype class it is enough to define @Scope annotation with value "prototype":

@Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class MyProtoBean {
   // ... 
}

4. Finally, inject bean in another class with ObjectFactory:

import com.example.proto.MyProtoBean;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;


@Component
public class ProtoUser {

    private final MyProtoBean myProtoBean;

    @Autowire
    public ProtoUser(ObjectFactory<MyProtoBean> protoFactory) {
      this.myProtoBean = protoFactory.getObject();
    }
}

You can use other ways to inject prototype beans into a singleton instance, although I didn't test them.

[Matthias Gaiser _K15t_]

@Vasil'ev Nickolay - you made my day today. This is not at all documented in the spring scanner, but worked perfectly fine when I ran into some problems with our app upgrade to Jira 10 where we also updated the spring scanner accordingly.

Thanks a lot.