h2. Motivation
CDI apps usually consist of user business logic, libraries (e.g. DeltaSpike) and integration stuff (e.g. WildFly subsystems - JSF, Bean Validation, Batch). Most applications only use a small part of the beans provided by libraries and integrations. However, Weld has to retain the metadata for all beans in memory.
Measurements showed that a simple bean/producer method takes approx. 1-2 KB. Batch subsystem which is automatically enabled in WildFly registers ~ 60 beans (producers). Right now, one could exclude the subsystem completely. But this approach has drawbacks. E.g. if you only use one the beans you cannot exclude the whole subsystem/bean archive.
h2. Solution
Allow to instruct Weld to find "unused" beans and drop their metadata after bootstrap.
An unused bean:
* is not a built-in bean, extension, interceptor, decorator
* does not have a name
* does not declare an observer
* is not cannot be injected in any injection point
* does not declare a producer which is injected in any injection point
* TODO
h2. Problems:
# Programmatic lookup - no easy way to detect, at least {{Instance<>}} injection points should be considered
# EE components might be installed after Weld initialization finished - this cleanup must be performed after all EE components are installed
h2. Configuration
User should be able to exclude some beans from removal. E.g. a regular expression might be used to match the bean classes which are excluded. |
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