Provide a non-@Component-sterotype annotation that tags a bean class to be scanned fro @Bean annotations [SPR-5795]

[spring-projects-issues]

Mark Kralj-Taylor opened SPR-5795 and commented

Spring component-scanning discovers @Component stereotype annotated classes.
One thing that Spring does for these 'components' is to scan the class for @Bean annotations.

We have a use-case where we want a bean's class to be scanned for @Bean annotations, but without the bean being @Component stereotype annotated.

• We want Spring to scan for @Bean annotations in the class for some beans configured in explicitly (esp in XML config) to Spring.

Please can spring provide a new annotation that:

• marks a class so Spring scans it for @Bean annotations, when it is used as a Spring bean
• without making the class eligible for component-scanning

Our specific use case is where Spring beans have internal components that Spring needs to know about so they can be detected by JMX exporting.

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Affects: 3.0 M3

Referenced from: commits b8c1130

[spring-projects-issues]

Mark Kralj-Taylor commented

Expect it makes sense for the new annotation to ask Spring to scan bean class for the other new annotations as well as @Bean given in Spring 3 docs (@Value etc)

http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/ch02s04.html#new-java-configuration

[spring-projects-issues]

Mark Kralj-Taylor commented

Would it make sense for context:annotation-config/ to turn on Spring respecting @Bean, @Value etc annotations in beans?

In this case Spring would only check the beans it knows about (that are explicitly configured), there woudl be no calsspath scanning to pick-up beans.

We see component scanning (<context:component-scan ...>) to 'pick-up' beans as more 'magic' than Spring respecting annotations on beans that are explicitly provided to Spring (e.g. in Spring XML config).

If respecting @Bean and @Value etc is too much functionality (magic) for context:annotation-config/ to turn on then perhaps it could be attribute option of an option of context:annotation-config/ or a different annotation.

[spring-projects-issues]

Juergen Hoeller commented

As previously discussed, ConfigurationClassPostProcessor is automatically registered by context:annotation-config/ already. We are now also introspecting methods of registered bean classes, detecting @Bean methods there even if the containing class is not annotated with an @Configuration or @Component stereotype. This isn't too expensive since we have to parse the metadata for such bean classes anyway; introspecting methods on the bean class is quite fast then since we parsed the entire class anyway.

Juergen