@Configuration classes may implement ImportAware in order to be injected
with the AnnotationMetadata of their @Import'ing class.
Includes the introduction of a new PriorityOrdered
ImportAwareBeanPostProcessor that handles injection of the
importing class metadata.
Includes the introduction of AnnotationUtils#findAllAnnotationAttributes
to support iterating through all annotations declared on a given type
and interrogating each for the presence of a meta-annotation. See tests
for details.
The overloading necessary to preserve the new signature as well as
the old causes ambiguities leading to deprecation warnings in some
caller scenarios.
Previously errors were being raised when trying to inject @Value
annotated paramaters such as:
@Feature
public FeatureSpec feature(@Value("#{environment['foo']}") String foo) {
return new FeatureSpec(foo);
}
This is not so much because dependency resolution of @Value-annotated
types was failing, but rather because the 'early bean reference'
proxying mechanism was throwing an exception if any final type was
detected as a parameter. This is of course because final types are
non-subclassable by CGLIB. On review, however, it's obvious that
certain final types must be allowed for injection. @Value injection
is an obvious one, but the rarer case of a Spring bean of type String
or int is another.
The explicit guard against final types as parameters to @Feature methods
has been removed. Final types are still checked for, however, and if
found, no proxing is attempted. The dependency is immediately resolved
against the current BeanFactory and injected into the @Feature method.
This means that @Value injection, @Qualifier injection, etc all work
as expected, but does mean that premature bean instantiation may occur
if a user unwittingly injects non-String, non-primitive final bean types
as @Feature method parameters.
Issue: SPR-7974
CGLIB-enhanced @Configuration subclasses now implement DisposableBean
such that Enhancer.registerStaticCallbacks(subclass, null) is invoked
on container shutdown. This ensures that garbage collection can work
properly and avoids memory consumption issues for applications that
create and destroy many application contexts within the same JVM.
Issue: SPR-7901
context:property-placeholder extends 'propertyPlaceholder' type
defintion once again. This relationship was inadvertently removed in
3.1 M1, and the effect was that XML tooling would raise errors on
use of attributes like 'location'.
The updated schema has also been published to
http://www.springframework.org/schema/context/spring-context-3.1.xsd
Issue: SPR-8037
Prove that injection of special container types such as ResourceLoader,
BeanFactory, etc already works with the current implementation of
@Feature methods.
Issue: SPR-7975
Current STS version of Spring (3.0.5) does not contain
the BeanUtils.instantiateClass(Class<?>, Class<T>) signature
that was added in 3.1.0, therefore NoSuchMethodErrors are
being thrown when STS classloads and delegates to
3.1.0 NamespaceHandler and BeanDefinitionParser implementations
on the user project classpath.
In this case, it's AbstractSpecificationBeanDefinitionParser
doing the calling to the unknown new method. In this specific
example, reverting back to the old single-arg signature is actually
not a problem, because it does accept Class<T> and returns an
instance of type T, which was the desired behavior in the first
place.
The newer signature remains in order to accommodate callers
who do not know the generic type of the Class to be instantiated
(i.e. Class<?>), but do know the type that it should be assignable
to -- this becomes the second argument Class<T>, and an instance
of type T is returned (if indeed it is assignable to the specified
type; otherwise IllegalArgumentException.
Chris Beams
Costin Leau
Micha Kiener
Sam Brannen
Rossen Stoyanchev
Juergen Hoeller