Designed primarily for use in conjunction with web applications
to provide a convenient mechanism for configuring the container
programmatically.
ApplicationContextInitializer implementations are specified through the
new "contextInitializerClasses" servlet context parameter, then detected
and invoked by ContextLoader in its customizeContext() method.
In any case, the semantics of ApplicationContextInitializer's
initialize(ConfigurableApplicationContext) method require that
invocation occur *prior* to refreshing the application context.
ACI implementations may also implement Ordered/PriorityOrdered and
ContextLoader will sort instances appropriately prior to invocation.
Specifically, this new support provides a straightforward way to
programmatically access the container's Environment for the purpose
of adding, removing or otherwise manipulating PropertySource objects.
See Javadoc for further details.
Also note that ApplicationContextInitializer semantics overlap to
some degree with Servlet 3.0's notion of ServletContainerInitializer
classes. As Spring 3.1 development progresses, we'll likely see
these two come together and further influence one another.
* PropertySources is now an Iterable<PropertySource> in favor of
exposing an asList() method
* Otherwise reduced the set of methods exposed by PropertySources to the
absolute minimum
* Added Javadoc for both types and all methods
* 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.
AbstractEnvironment delegates to an underlying ConfigurationService when
processing methods such as getProperty(String name, Class<?> targetType)
Accessor methods have been added to the ConfigurableEnvironment
interface that allow this service to be updated or replaced.
There is no longer a reserved default profile named 'default'. Rather,
users must explicitly specify a default profile or profiles via
ConfigurableEnvironment.setDefaultProfiles(String...)
- or -
spring.profile.default="pD1,pD2"
Per above, the setDefaultProfile(String) method now accepts a variable
number of profile names (one or more). This is symmetrical with the
existing setActiveProfiles(String...) method.
A typical scenario might involve setting both a default profile as a
servlet context property in web.xml and then setting an active profile
when deploying to production.
Before this change, the following properties could be used to manipulate
Spring profile behavior:
-DspringProfiles=p1,p2
-DdefaultSpringProfile=pD
These properties have been renamed to follow usual Java conventions for
property naming:
-Dspring.profile.active=p1,p2
-Dspring.profile.default=pD
'default' is now a reserved profile name, indicating
that any beans defined within that profile will be registered
unless another profile or profiles have been activated.
Examples below are expressed in XML, but apply equally when
using the @Profile annotation.
EXAMPLE 1:
<beans>
<beans profile="default">
<bean id="foo" class="com.acme.EmbeddedFooImpl"/>
</beans>
<beans profile="production">
<bean id="foo" class="com.acme.ProdFooImpl"/>
</beans>
</beans>
In the case above, the EmbeddedFooImpl 'foo' bean will be
registered if:
a) no profile is active
b) the 'default' profile has explicitly been made active
The ProdFooImpl 'foo' bean will be registered if the 'production'
profile is active.
EXAMPLE 2:
<beans profile="default,xyz">
<bean id="foo" class="java.lang.String"/>
</beans>
Bean 'foo' will be registered if any of the following are true:
a) no profile is active
b) 'xyz' profile is active
c) 'default' profile has explicitly been made active
d) both (b) and (c) are true
Note that the default profile is not to be confused with specifying no
profile at all. When the default profile is specified, beans are
registered only if no other profiles are active; whereas when no profile
is specified, bean definitions are always registered regardless of which
profiles are active.
The default profile may be configured programmatically:
environmnent.setDefaultProfile("embedded");
or declaratively through any registered PropertySource, e.g. system properties:
-DdefaultSpringProfile=embedded
Assuming either of the above, example 1 could be rewritten as follows:
<beans>
<beans profile="embedded">
<bean id="foo" class="com.acme.EmbeddedFooImpl"/>
</beans>
<beans profile="production">
<bean id="foo" class="com.acme.ProdFooImpl"/>
</beans>
</beans>
It is unlikely that use of the default profile will make sense in
conjunction with a statically specified 'springProfiles' property.
For example, if 'springProfiles' is specified as a web.xml context
param, that profile will always be active for that application,
negating the possibility of default profile bean definitions ever
being registered.
The default profile is most useful for ensuring that a valid set of
bean definitions will always be registered without forcing users
to explictly specify active profiles. In the embedded vs. production
examples above, it is assumed that the application JVM will be started
with -DspringProfiles=production when the application is in fact in
a production environment. Otherwise, the embedded/default profile bean
definitions will always be registered.
Branch in question is 'env' branch from git://git.springsource.org/sandbox/cbeams.git; merged into
git-svn repository with:
git merge -s recursive -Xtheirs --no-commit env
No merge conflicts, but did need to
git rm spring-build
prior to committing.
With this change, Spring 3.1.0 development is now happening on SVN
trunk. Further commits to the 3.0.x line will happen in an as-yet
uncreated SVN branch. 3.1.0 snapshots will be available
per the usual nightly CI build from trunk.
When using PropertiesLoaderSupport implementations (principally
PropertyPlaceholderConfigurer), an assumption was made that any
Resource representing a set of properties must be file-based. SPR-7547
exposed the fact that if a non-file-based Resource implementation such
as ByteArrayResource were passed in, an IllegalStateException would be thrown
from the AbstractResource base class' implementation of getFilename().
This is now patched, and PropertiesLoaderSupport implementations treat
Resource implementations equally, regardless of file-orientation.
See also SPR-7552.
Juergen Hoeller
Keith Donald
Chris Beams
Sam Brannen
Arjen Poutsma
Mark Fisher