This change is in support of certain polymorphism cases in
@Configuration class inheritance hierarchies. Consider the following
scenario:
@Configuration
public abstract class AbstractConfig {
public abstract Object bean();
}
@Configuration
public class ConcreteConfig {
@Override
@Bean
public BeanPostProcessor bean() { ... }
}
ConcreteConfig overrides AbstractConfig's #bean() method with a
covariant return type, in this case returning an object of type
BeanPostProcessor. It is critically important that the container
is able to detect the return type of ConcreteConfig#bean() in order
to instantiate the BPP at the right point in the lifecycle.
Prior to this change, the container could not do this.
AbstractAutowireCapableBeanFactory#getTypeForFactoryMethod called
ReflectionUtils#getAllDeclaredMethods, which returned Method objects
for both the Object and BeanPostProcessor signatures of the #bean()
method. This confused the implementation sufficiently as not to
choose a type for the factory method at all. This means that the
BPP never gets detected as a BPP.
The new method being introduced here, #getUniqueDeclaredMethods, takes
covariant return types into account, and filters out duplicates,
favoring the most specific / narrow return type.
Additionally, it filters out any CGLIB 'rewritten' methods, which
is important in the case of @Configuration classes, which are
enhanced by CGLIB. See the implementation for further details.
Consolidating internal bean name and aspect class name constats within
AnnotationConfigUtils to allow access from both the context.config
and context.annotation packages without creating a relationship between
the two of them (they are unrelated leaf nodes in the packaging
currently).
The .transaction module does not have a similar utils class and already
has a relationship from transaction.config -> transaction.annotation,
so placing the constants in .annotation.TransactionManagementCapability
to be referenced by .config.AnnotationDrivenBeanDefinitionParser
@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.
Feature-related support such as @Feature, @FeatureConfiguration,
and FeatureSpecification types will be replaced by framework-provided
@Configuration classes and convenience annotations such as
@ComponentScan (already exists), @EnableAsync, @EnableScheduling,
@EnableTransactionManagement and others.
Issue: SPR-8012,SPR-8034,SPR-8039,SPR-8188,SPR-8206,SPR-8223,
SPR-8225,SPR-8226,SPR-8227
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
Prove that injection of special container types such as ResourceLoader,
BeanFactory, etc already works with the current implementation of
@Feature methods.
Issue: SPR-7975
Introduce FeatureSpecification interface and implementations
FeatureSpecification objects decouple the configuration of
spring container features from the concern of parsing XML
namespaces, allowing for reuse in code-based configuration
(see @Feature* annotations below).
* ComponentScanSpec
* TxAnnotationDriven
* MvcAnnotationDriven
* MvcDefaultServletHandler
* MvcResources
* MvcViewControllers
Refactor associated BeanDefinitionParsers to delegate to new impls above
The following BeanDefinitionParser implementations now deal only
with the concern of XML parsing. Validation is handled by their
corresponding FeatureSpecification object. Bean definition creation
and registration is handled by their corresponding
FeatureSpecificationExecutor type.
* ComponentScanBeanDefinitionParser
* AnnotationDrivenBeanDefinitionParser (tx)
* AnnotationDrivenBeanDefinitionParser (mvc)
* DefaultServletHandlerBeanDefinitionParser
* ResourcesBeanDefinitionParser
* ViewControllerBeanDefinitionParser
Update AopNamespaceUtils to decouple from XML (DOM API)
Methods necessary for executing TxAnnotationDriven specification
(and eventually, the AspectJAutoProxy specification) have been
added that accept boolean arguments for whether to proxy
target classes and whether to expose the proxy via threadlocal.
Methods that accepted and introspected DOM Element objects still
exist but have been deprecated.
Introduce @FeatureConfiguration classes and @Feature methods
Allow for creation and configuration of FeatureSpecification objects
at the user level. A companion for @Configuration classes allowing
for completely code-driven configuration of the Spring container.
See changes in ConfigurationClassPostProcessor for implementation
details.
See Feature*Tests for usage examples.
FeatureTestSuite in .integration-tests is a JUnit test suite designed
to aggregate all BDP and Feature* related tests for a convenient way
to confirm that Feature-related changes don't break anything.
Uncomment this test and execute from Eclipse / IDEA. Due to classpath
issues, this cannot be compiled by Ant/Ivy at the command line.
Introduce @FeatureAnnotation meta-annotation and @ComponentScan impl
@FeatureAnnotation provides an alternate mechanism for creating
and executing FeatureSpecification objects. See @ComponentScan
and its corresponding ComponentScanAnnotationParser implementation
for details. See ComponentScanAnnotationIntegrationTests for usage
examples
Introduce Default[Formatting]ConversionService implementations
Allows for convenient instantiation of ConversionService objects
containing defaults appropriate for most environments. Replaces
similar support originally in ConversionServiceFactory (which is now
deprecated). This change was justified by the need to avoid use
of FactoryBeans in @Configuration classes (such as
FormattingConversionServiceFactoryBean). It is strongly preferred
that users simply instantiate and configure the objects that underlie
our FactoryBeans. In the case of the ConversionService types, the
easiest way to do this is to create Default* subtypes. This also
follows convention with the rest of the framework.
Minor updates to util classes
All in service of changes above. See diffs for self-explanatory
details.
* BeanUtils
* ObjectUtils
* ReflectionUtils
PropertySourcesPlaceholderConfigurer accommodates recent changes in
Environment and PropertySource APIs, e.g. no longer assuming enumerability
of property names.
PSPC reuses as much functionality as possible from
AbstractPropertyPlaceholderConfigurer, but overrides
postProcessBeanFactory() and defines its own variation on
processProperties() in order to accept a PropertyResolver rather than
a PropertySource.
AbstractPropertyPlaceholderConfigurer introduces doProcessProperties()
method to encapsulate that which is actually common, such as the
visiting of each bean definition once a StringValueResolver has been
created in the subclass.
* Environment now extends PropertyResolver
* Environment no longer exposes resolver and sources
* PropertySource is String,Object instead of String,String
* PropertySource no longer assumes enumerability of property names
* Introduced EnumerablePropertySource for those that do have enumerable property names
Decomposed Environment interface into PropertySources, PropertyResolver
objects
Environment interface and implementations are still present, but
simpler.
PropertySources container aggregates PropertySource objects;
PropertyResolver provides search, conversion, placeholder
replacement. Single implementation for now is
PropertySourcesPlaceholderResolver
Renamed EnvironmentAwarePropertyPlaceholderConfigurer to
PropertySourcesPlaceholderConfigurer
<context:property-placeholder/> now registers PSPC by default, else
PPC if systemPropertiesMode* settings are involved
Refined configuration and behavior of default profiles
See Environment interface Javadoc for details
Added Portlet implementations of relevant interfaces:
* DefaultPortletEnvironment
* PortletConfigPropertySource, PortletContextPropertySource
* Integrated each appropriately throughout Portlet app contexts
Added protected 'createEnvironment()' method to AbstractApplicationContext
Subclasses can override at will to supply a custom Environment
implementation. In practice throughout the framework, this is how
Web- and Portlet-related ApplicationContexts override use of the
DefaultEnvironment and swap in DefaultWebEnvironment or
DefaultPortletEnvironment as appropriate.
Introduced "stub-and-replace" behavior for Servlet- and Portlet-based
PropertySource implementations
Allows for early registration and ordering of the stub, then
replacement with actual backing object at refresh() time.
Added AbstractApplicationContext.initPropertySources() method to
support stub-and-replace behavior. Called from within existing
prepareRefresh() method so as to avoid impact with
ApplicationContext implementations that copy and modify AAC's
refresh() method (e.g.: Spring DM).
Added methods to WebApplicationContextUtils and
PortletApplicationContextUtils to support stub-and-replace behavior
Added comprehensive Javadoc for all new or modified types and members
Added XSD documentation for all new or modified elements and attributes
Including nested <beans>, <beans profile="..."/>, and changes for
certain attributes type from xsd:IDREF to xsd:string
Improved fix for detecting non-file based Resources in
PropertiesLoaderSupport (SPR-7547, SPR-7552)
Technically unrelated to environment work, but grouped in with
this changeset for convenience.
Deprecated (removed) context:property-placeholder
'system-properties-mode' attribute from spring-context-3.1.xsd
Functionality is preserved for those using schemas up to and including
spring-context-3.0. For 3.1, system-properties-mode is no longer
supported as it conflicts with the idea of managing a set of property
sources within the context's Environment object. See Javadoc in
PropertyPlaceholderConfigurer, AbstractPropertyPlaceholderConfigurer
and PropertySourcesPlaceholderConfigurer for details.
Introduced CollectionUtils.toArray(Enumeration<E>, A[])
Work items remaining for 3.1 M2:
Consider repackaging PropertySource* types; eliminate internal use
of SystemPropertyUtils and deprecate
Further work on composition of Environment interface; consider
repurposing existing PlaceholderResolver interface to obviate need
for resolve[Required]Placeholder() methods currently in Environment.
Ensure configurability of placeholder prefix, suffix, and value
separator when working against an AbstractPropertyResolver
Add JNDI-based Environment / PropertySource implementatinos
Consider support for @Profile at the @Bean level
Provide consistent logging for the entire property resolution
lifecycle; consider issuing all such messages against a dedicated
logger with a single category.
Add reference documentation to cover the featureset.
