Prior to this change, an instance of ConfigurationClassPostProcessor
would throw IllegalStateException if its
postProcessBeanDefinitionRegistry method were called more than once.
This check is important to ensure that @Configuration classes are
not proxied by CGLIB multiple times, and works for most normal use
cases.
However, if the same CCPP instance is used to process multiple
registries/factories/contexts, this check creates a false negative
because it does not distinguish between invocations of
postProcessBeanDefinitionRegistry across different registries.
A use case for this, though admittedly uncommon, would be creating
a CCPP instance and registering it via
ConfigurableApplicationContext#addBeanDefinitionPostProcessor against
several ApplicationContexts. In such a case, the same CCPP instance
will post-process multiple different registry instances, and throw the
above mentioned exception.
With this change, CCPP now performs lightweight tracking of the
registries/beanFactories that it has already processed by recording
the identity hashcodes of these objects. This is only slightly more
complex than the previous boolean-based 'already processed' flags, and
prevents this issue (however rare it may be) from occurring.
Issue: SPR-8527
Prior to this change, @EnableTransactionManagement (via the
ProxyTransactionManagementConfiguration class) did not properly
register its auto-proxy creator through the usual AopConfigUtils
methods. It was trying to register the APC as a normal @Bean method,
but this causes issues (SPR-8494) with the logic in
AopConfigUtils#registerOrEscalateApcAsRequired, which expects the APC
bean definition to have a beanClassName property. When the APC is
registered via a @Bean definition, it is actually a
factoryBean/factoryMethod situation with no directly resolvable
beanClass/beanClassName.
To solve this problem, ImportSelector#selectImports has been refactored
to accept an ImportSelector.Context instance. This object contains the
AnnotationMetadata of the importing class as well as the enclosing
BeanDefinitionRegistry to allow for the kind of conditional bean
registration necessary here. In this case, the bean definition that
must be registered conditionally is that of the auto-proxy creator.
It should only be registered if AdviceMode == PROXY, and thus the
ImportSelector is an appropriate place to make this happen. It must
happen as a BeanDefinition (rather than a @Bean method) for
compatibility with AopConfigUtils, and working with the
BeanDefinitionRegistry API allows for that. This change does mean that
in certain cases like this one, #selectImports has container modifying
side effects. Documentation has been updated to reflect.
Issue: SPR-8411, SPR-8494
For the particular use case detailed in SPR-8514, with this change we
now attempt to determine the object type of a FactoryBean through its
generic type parameter if possible.
For (a contrived) example:
@Configuration
public MyConfig {
@Bean
public FactoryBean<String> fb() {
return new StringFactoryBean("foo");
}
}
The implementation will now look at the <String> generic parameter
instead of attempting to instantiate the FactoryBean in order to call
its #getObjectType() method.
This is important in order to avoid the autowiring lifecycle issues
detailed in SPR-8514. For example, prior to this change, the following
code would fail:
@Configuration
public MyConfig {
@Autowired Foo foo;
@Bean
public FactoryBean<String> fb() {
Assert.notNull(foo);
return new StringFactoryBean("foo");
}
}
The reason for this failure is that in order to perform autowiring,
the container must first determine the object type of all configured
FactoryBeans. Clearly a chicken-and-egg issue, now fixed by this
change.
And lest this be thought of as an obscure bug, keep in mind the use case
of our own JPA support: in order to configure and return a
LocalContainerEntityManagerFactoryBean from a @Bean method, one will
need access to a DataSource, etc -- resources that are likely to
be @Autowired across @Configuration classes for modularity purposes.
Note that while the examples above feature methods with return
types dealing directly with the FactoryBean interface, of course
the implementation deals with subclasses/subinterfaces of FactoryBean
equally as well. See ConfigurationWithFactoryBeanAndAutowiringTests
for complete examples.
There is at least a slight risk here, in that the signature of a
FactoryBean-returing @Bean method may advertise a generic type for the
FactoryBean less specific than the actual object returned (or than
advertised by #getObjectType for that matter). This could mean that an
autowiring target may be missed, that we end up with a kind of
autowiring 'false negative' where FactoryBeans are concerned. This is
probably a less common scenario than the need to work with an autowired
field within a FactoryBean-returning @Bean method, and also has a clear
workaround of making the generic return type more specific.
Issue: SPR-8514
isCglibProxy* methods in AopUtils are useful in lower-level modules,
i.e. those that cannot depend on .aop. Therefore copied these methods
to ClassUtils; deprecated the existing ones in AopUtils and now
delegating to the new location; switched all usage of
AopUtils#isCglibProxy* within the framework to use
ClassUtils#isCglibProxy* instead.
Even after applying @Ignore to these tests at the class level, they
still run (and fail) under ant when the jmxremote_optional jar is not
present. See the issues mentioned below for information on how these
tests will be re-enabled.
Issue: SPR-8089, SPR-8093, SPR-8458
Prior to this change, JndiPropertySource worked directly against a JNDI
Context instance as its 'source' object. This works well enough, but is
not nearly as fully-featured as Spring's existing JndiLocatorDelegate.
This change refactors JndiPropertySource from relying on an underlying
Context to relying on an underlying JndiLocatorDelegate. By default,
the delegate's "resourceRef" property is set to true, meaning that the
implementation will always try to prepand a given name with
"java:comp/env/" before looking up the name, and upon failure will drop
back to the given name sans prefix.
See JndiPropertySource Javadoc for complete details.
Issue: SPR-8490
Move JNDI_PROPERTY_SOURCE_ENABLED_FLAG from JndiPropertySource to
StandardServletEnvironment, as this is the only context in which the
constant makes sense.
Prior to this change, @Autowired injection against an instance of a
subclass having different visibility than its superclass would fail
if the @Autowired method is declared only in the superclass. This is due
to an apparent change in the rules around bridge method generation
between Java 5 and Java 6, and possibly even varying across compiler
vendors.
Now, BridgeMethodResolver is used consistently when detecting
@Autowired, @Inject and @Resource metadata to bypass these bridge
methods if they exist.
Issue: SPR-7900
Prior to this change, AbstractAutowireCapableBeanFactory did not support
a default ParameterNameDiscoverer. This meant that attempting to use
<constructor-arg name=".."> syntax would fail (with a fairly obscure
exception) as that feature depends on a ParameterNameDiscoverer to
introspect the constructor arguments.
This lack of a default was originally intended to avoid a dependency on
ASM, but now that (a) .asm is a built-in module and (b) .beans has a
non-optional compile-time dependency on .asm, there is no reason not to
provide this default.
The net effect is that in a number of locations throughout the
framework, namely in GenericApplicationContext and
AbstractRefreshableApplicationContext, it is no longer necessary to
explicitly call AACBF#setParameterNameDiscoverer. This also means that
using a naked BeanFactory (likely for testing scenarios) is that much
easier.
Issue: SPR-8184
As of SPR-8093, jmxremote_optional.jar is present on the build
server in jre/lib/ext, but it is not by default present on local
developer / user machines, meaning that the build ends up broken
by default.
Issue: SPR-8089, SPR-8093, SPR-8458
Juergen Hoeller
Costin Leau
Chris Beams
David Syer
Sam Brannen
Mark Fisher
Oliver Gierke