Allow usage of BeanNameGenerator in ImportBeanDefinitionRegistrars

[odrotbohm]

A BeanNameGenerator can be configured for usage in component scanning configuration classes. That support allows custom annotation based activation of functionality via annotations importing an ImportBeanDefinitionRegistrar. Its primary callback method unfortunately currently doesn't provide access to the BeanNameGenerator potentially provided so that a customization of that generator cannot be considered for components registered via the registrar.

It would be nice, if there was a way to consume the BeanNameGenerator to allow components being registered to follow the configured naming strategy.

[odrotbohm]

It looks like we're getting the generator that's used for the configuration class scanning, not the one used to name scanned components. I've put in check for the enclosing class of the provided instance to only opt in using it if it's not ConfigurationClassPostProcessor. Is there maybe a chance we can expose the default one used in a slightly more convenient way (a constant in ConfigurationClassPostProcessor maybe)?

[sbrannen]

Reopening to consider comments from @odrotbohm.