Provide a way to predict bean types without initializing FactoryBeans

[philwebb]

See this comment for details.

I don't think we currently have a way to tell the predicted type of a bean without initializing it. It might be nice if we could either surface a getType(String name, boolean allowEagerInit) or perhaps add a callback based approach similar to the existing getBeanNames... methods:

<T> void doWithBeanNamesForType(@Nullable Class<T> type, boolean includeNonSingletons, boolean allowEagerInit, BiConsumer<String, Class<T>> consumer);

We should wait until #23341 is merged before taking this on.

[jhoeller]

@philwebb Would you expect such a getType(String name, boolean allowFactoryBeanInit) method to be available on the BeanFactory interface, not just on the factory implementation hierarchy? And the flag would only affect the internal getTypeForFactoryBean call, I suppose?

[philwebb]

@jhoeller I haven't given too much thought, but I assumed on the interface next to BeanFactory.getType(String name) would be best. It probably doesn't matter too from our side since we can always cast.

the flag would only affect the internal getTypeForFactoryBean call, I suppose?

I think so. I think all the other areas of the current implementation don't cause initialization.