The registration of more than one ConfigurationClassPostProcessor
results in the double-enhancement of @Configuration classes, i.e. a
two-deep CGLIB subclass hierarchy is created.
As a side-effect of changes introduced in 3.1 M2 fixing SPR-8080, this
behavior now results in an infinite loop at CGLIB callback processing
time, leading to a StackOverflowException which is then suppressed by
the container, and ultimately results in the user being presented with
an unintuitive "Bean 'x' is not already in creation" exception.
This fix introduces a marker interface 'EnhancedConfiguration' to be
implemented by all generated @Configuration subclasses. The
configuration class enhancer can then behave in an idempotent fashion
by checking to see whether a candidate @Configuration class is already
assignable to this type i.e. already enhanced and ignore it if so.
Naturally, users should avoid registering more than one
ConfigurationClassPostProcessor, but this is not always possible. As
with the case in point, SPR-8824 originates from problems with
spring-data-neo4j, which explicitly registers its own
ConfigurationClassPostProcessor. The user has little control over this
arrangement, so it is important that the framework is defensive as
described above.
Issue: SPR-8824
Separate concerns of @Configuration class selection from the need to
register certain infrastructure beans such as auto proxy creators.
Prior to this change, ImportSelector implementations were responsible
for both of these concerns, leading to awkwardness and duplication.
Also introduced in this change is ImportBeanDefinitionRegistrar and
two implementations, AutoProxyRegistrar and AspectJAutoProxyRegistrar.
See the refactored implementations of CachingConfigurationSelector,
TransactionManagementConfigurationSelector to see the former;
AspectJAutoProxyConfigurationSelector to see the latter.
ImportSelector and ImportBeanDefinitionRegistrar are both handled as
special-case arguments to the @Import annotation within
ConfigurationClassParser.
These refactorings are important because they ensure that Spring users
will be able to understand and extend existing @Enable* annotations
and their backing ImportSelector and @Configuration classes, as well
as create their own with a minimum of effort.
Also eliminate all 'cache definition' language in favor of
'cache operation' in comments, method and parameter names (most
classes had already been refactored to this effect).
Unfortunately creates a large diff due to whitespace changes as well as
false attribution of authorship from a git/svn 'blame' perspective.
Be sure to perform diffs using `git diff -w` or `svn diff -w` when
reviewing recent changes to these sources to ignore all whitespace.
In favor of existing #setCacheOperationSources(CacheOperationSource...)
Also polish Javadoc throughout, replacing stale references to
CacheDefinitionSource where appropriate as well as other minor changes
Facilitates type-safe programmatic configuration from @Bean methods:
@Bean
public CacheManager cacheManager() {
SimpleCacheManager cm = new SimpleCacheManager();
cm.setCaches(Arrays.asList(
new ConcurrentMapCache("default"),
new ConcurrentMapCache("primary"),
new ConcurrentMapCache("secondary")
));
return cm;
}
Prior to this change, the code above would have raised errors on the
Arrays.asList() call because it returns a Collection<? extends Cache>
as opposed to Collection<Cache>.
After this change, AbstractCacheManager expects
Collection<? extends Cache> throughout.
There was some question about whether enabling subclass proxies via
proxyTargetClass / proxy-target-class settings would break annotation-
based demarcation of joinpoints due to inability to discover those
annotations in various scenarios. The provided tests prove that in
any conceivable case, these annotations (@Transactional, at least)
are discovered in a consistent fashion, meaning that switching proxy
strategies should be transparent to the application and honor
intended annotation semantics.
Anywhere the value of a destroy method may be expressed, specifying
the value "(inferred)" now indicates that the container should attempt
to automatically discover a destroy method. This functionality is
currently limited to detecting public, no-arg methods named 'close';
this is particularly useful for commonly used types such as Hibernate
SessionFactory most JDBC DataSource implementations, JMS connection
factories, and so forth.
This special value is captured as the constant
AbstractBeanDefinition#INFER_METHOD, which in turn serves as the default
value of the @Bean#destroyMethod attribute.
For example in the following case
@Bean
public BasicDataSource dataSource() { ... }
the container will automatically detect BasicDataSource#close and invoke
it when the enclosing ApplicationContext is closed. This is exactly
equivalent to
@Bean(destroyMethod="(inferred)")
public BasicDataSource dataSource() { ... }
A user may override this inference-by-default convention simply by
specifying a different method
@Bean(destroyMethod="myClose")
public MyBasicDataSource dataSource() { ... }
or, in the case of a bean that has an otherwise inferrable 'close'
method, but the user wishes to disable handling it entirely, an empty
string may be specified
@Bean(destroyMethod="")
public MyBasicDataSource dataSource() { ... }
The special destroy method name "(inferred)" may also be specified in
an XML context, e.g.
<bean destroy-method="(inferred)">
or
<beans default-destroy-method="(inferred)">
Note that "(inferred)" is the default value for @Bean#destroyMethod,
but NOT for the destroy-method and default-destroy-method attributes
in the spring-beans XML schema.
The principal reason for introducing this feature is to avoid forcing
@Configuration class users to type destroyMethod="close" every time a
closeable bean is configured. This kind of boilerplate is easily
forgotten, and this simple convention means the right thing is done
by default, while allowing the user full control over customization or
disablement in special cases.
Issue: SPR-8751
Remove all convenience variants of #findAllAnnotationAttributes and
refactor the remaining method to accept a MetadataReaderFactory
instead of creating its own SimpleMetadataReaderFactory internally.
This allows clients to use non-default class loaders as well as
customize the particular MetadataReaderFactory to be used (e.g.
'simple' vs 'caching', etc).
Issue: SPR-8752
Removed formal deprecation warnings for AbstractSingletonFactoryBean and
its TransactionProxyFactoryBean and CacheProxyFactoryBean subclasses.
This is principally because TPFB is still used by Grails and could
conceivably be used to good effect by any third-party framework in a
similar fashion. CPFB is new with 3.1, but similar use is predictable.
Deprecations have been replaced by strong recommendations that users
avoid these types in modern Spring applications and favor the use of
namespaces and annotatinos, such as tx: and @Transactional (around
since Spring 2.x) and cache: and @Cacheable.
Issue: SPR-8680, SPR-8686
In anticipation of 'destroy method inference' feature, introduce
ConfigurationClassUtils#INFER_METHOD and update @Bean#destroyMethod to
reflect its use.
Issue: SPR-8751
Cite original inspiriation by Domain-Driven Design, but make clear the
flexible and general-purpose nature of Spring's stereotype annotations
such as @Repository and @Service.
Also update @Repository Javadoc with more explicit instructions about
switching on exception translation through use of
PersistenceExceptionTranslationPostProcessor, and update PETPP Javadoc
for style as well as concrete examples of 'resource factories' that
implement the PersistenceExceptionTranslator interface
Issue: SPR-8691
Prior to this change, StandardServletEnvironment evaluated a
"jndiPropertySourceEnabled" flag to determine whether or not to add a
JndiPropertySource. Following the changes introduced in SPR-8490, there
is now no reason not to enable a JNDI property source by default. This
change eliminates the support for "jndiPropertySourceEnabled" and adds
a JndiPropertySource automatically.
Issue: SPR-8545, SPR-8490
