Prior to this commit, there existed several isEmpty() methods scattered
across various utilities such as ObjectUtils, CollectionUtils, and
StringUtils; however, each of these methods requires a cast to the type
supported for that particular variant.
This commit introduces a general-purpose isEmpty(Object) method in
ObjectUtils that transparently supports multiple object types in a
central location without the need for casts or juggling multiple
utility classes.
Issue: SPR-13119
Provide a mean to detect the actual ResolvableType based on a instance as
a counter measure to type erasure.
Upgrade the event infrastructure to detect if the event (or the payload)
implements such interface. When this is the case, the return value of
`getResolvableType` is used to validate its generic type against the
method signature of the listener.
Issue: SPR-13069
This commit introduces a "synthesized annotation" alternative to
getAnnotationAttributes() in AnnotatedElementUtils, analogous to the
recently introduced findAnnotation() methods.
Issue: SPR-13082
Spring Framework 4.2 RC1 introduced support for synthesizing an
annotation from an existing annotation in order to provide additional
functionality above and beyond that provided by Java. Specifically,
such synthesized annotations provide support for @AliasFor semantics.
As luck would have it, the same principle can be used to synthesize an
annotation from any map of attributes, and in particular, from an
instance of AnnotationAttributes.
The following highlight the major changes in this commit toward
achieving this goal.
- Introduced AnnotationAttributeExtractor abstraction and refactored
SynthesizedAnnotationInvocationHandler to delegate to an
AnnotationAttributeExtractor.
- Extracted code from SynthesizedAnnotationInvocationHandler into new
AbstractAliasAwareAnnotationAttributeExtractor and
DefaultAnnotationAttributeExtractor implementation classes.
- Introduced MapAnnotationAttributeExtractor for synthesizing an
annotation that is backed by a map or AnnotationAttributes instance.
- Introduced a variant of synthesizeAnnotation() in AnnotationUtils
that accepts a map.
- Introduced findAnnotation(*) methods in AnnotatedElementUtils that
synthesize merged AnnotationAttributes back into an annotation of the
target type.
The following classes have been refactored to use the new support for
synthesizing AnnotationAttributes back into an annotation.
- ApplicationListenerMethodAdapter
- TestAnnotationUtils
- AbstractTestContextBootstrapper
- ActiveProfilesUtils
- ContextLoaderUtils
- DefaultActiveProfilesResolver
- DirtiesContextTestExecutionListener
- TestPropertySourceAttributes
- TestPropertySourceUtils
- TransactionalTestExecutionListener
- MetaAnnotationUtils
- MvcUriComponentsBuilder
- RequestMappingHandlerMapping
In addition, this commit also includes changes to ensure that arrays
returned by synthesized annotations are properly cloned first.
Issue: SPR-13067
Prior to this commit, when a nested array of annotations was
synthesized while adapting values within an AnnotationAttributes map,
the array was improperly replaced with an array of type Annotation[]
instead of an array of the concrete annotation type, which can lead to
unexpected run-time exceptions.
This commit fixes this bug by replacing annotations in the existing
array with synthesized versions of those annotations, thereby retaining
the original array's component type.
Issue: SPR-13077
This commit introduces support in AnnotationAttributes for retrieving
nested annotations that is on par with the existing type-safe support
for retrieving nested AnnotationAttributes.
Issue: SPR-13074
AnnotationAttributes has existed for several years, but none of the
"get" methods that make up its public API are documented. In many
cases, the behavior can be inferred from the name of the method, but
for some methods there are "hidden gems" and unexpected behavior
lurking behind the scenes.
This commit addresses this issue by documenting all public methods. In
addition, the hidden support for converting single elements into
single-element arrays has also been documented and tested.
Issue: SPR-13072
This commit introduces a test that will fail if SynthesizedAnnotation is
not public as is required by the contract for getProxyClass() in
java.lang.reflect.Proxy.
Issue: SPR-13057
Enable public visibility on SynthetizedAnnotation to allow annotation
outside its package to be proxied properly. This commit is pending a
unit test that actually reproduces the problem.
Issue: SPR-13057
This commit introduces first-class support for aliases for annotation
attributes. Specifically, this commit introduces a new @AliasFor
annotation that can be used to declare a pair of aliased attributes
within a single annotation or an alias from an attribute in a custom
composed annotation to an attribute in a meta-annotation.
To support @AliasFor within annotation instances, AnnotationUtils has
been overhauled to "synthesize" any annotations returned by "get" and
"find" searches. A SynthesizedAnnotation is an annotation that is
wrapped in a JDK dynamic proxy which provides run-time support for
@AliasFor semantics. SynthesizedAnnotationInvocationHandler is the
actual handler behind the proxy.
In addition, the contract for @AliasFor is fully validated, and an
AnnotationConfigurationException is thrown in case invalid
configuration is detected.
For example, @ContextConfiguration from the spring-test module is now
declared as follows:
public @interface ContextConfiguration {
@AliasFor(attribute = "locations")
String[] value() default {};
@AliasFor(attribute = "value")
String[] locations() default {};
// ...
}
The following annotations and their related support classes have been
modified to use @AliasFor.
- @ManagedResource
- @ContextConfiguration
- @ActiveProfiles
- @TestExecutionListeners
- @TestPropertySource
- @Sql
- @ControllerAdvice
- @RequestMapping
Similarly, support for AnnotationAttributes has been reworked to
support @AliasFor as well. This allows for fine-grained control over
exactly which attributes are overridden within an annotation hierarchy.
In fact, it is now possible to declare an alias for the 'value'
attribute of a meta-annotation.
For example, given the revised declaration of @ContextConfiguration
above, one can now develop a composed annotation with a custom
attribute override as follows.
@ContextConfiguration
public @interface MyTestConfig {
@AliasFor(
annotation = ContextConfiguration.class,
attribute = "locations"
)
String[] xmlFiles();
// ...
}
Consequently, the following are functionally equivalent.
- @MyTestConfig(xmlFiles = "test.xml")
- @ContextConfiguration("test.xml")
- @ContextConfiguration(locations = "test.xml").
Issue: SPR-11512, SPR-11513
Prior to this commit, the documentation in AnnotationUtils was
inconsistent, and at times even misleading, with regard to finding
annotations that are "present" or "directly present" on annotated
elements.
This commit defines the terminology used within AnnotationUtils and
introduces the explicit notion of "meta-present" to denote that
annotations are present within annotation hierarchies above annotated
elements.
Issue: SPR-13030
Sam Brannen
Stephane Nicoll
izeye
Sebastien Deleuze
Juergen Hoeller