2.1.2. @Requires
Annotating a class @Requires will cause the type to be ignored if the class dependencies can be satisfied. Any definitions on the type will not be processed:
• the managed bean, decorator, interceptor or session bean defined by the type
• any producer methods or producer fields defined on the type
• any observer methods defined on the type

For example:

@Requires(EntityManager.class)
class EntityManagerProducer {
@Produces EntityManager getEntityManager()

}