Spring-specific MessageSource implementation
that accesses resource bundles using specified basenames, participating in the
Spring ApplicationContext's resource loading.
In contrast to the JDK-based ResourceBundleMessageSource, this class uses
Properties instances as its custom data structure for messages,
loading them via a PropertiesPersister strategy
from Spring Resource handles. This strategy is not only capable of
reloading files based on timestamp changes, but also of loading properties files
with a specific character encoding. It will detect XML property files as well.
Note that the basenames set as "basenames" property
are treated in a slightly different fashion than the "basenames" property of
ResourceBundleMessageSource. It follows the basic ResourceBundle rule of not
specifying file extension or language codes, but can refer to any Spring resource
location (instead of being restricted to classpath resources). With a "classpath:"
prefix, resources can still be loaded from the classpath, but "cacheSeconds" values
other than "-1" (caching forever) might not work reliably in this case.
For a typical web application, message files could be placed in WEB-INF:
e.g. a "WEB-INF/messages" basename would find a "WEB-INF/messages.properties",
"WEB-INF/messages_en.properties" etc arrangement as well as "WEB-INF/messages.xml",
"WEB-INF/messages_en.xml" etc. Note that message definitions in a previous
resource bundle will override ones in a later bundle, due to sequential lookup.
This MessageSource can easily be used outside of an
ApplicationContext: it will use a
DefaultResourceLoader as default,
simply getting overridden with the ApplicationContext's resource loader
if running in a context. It does not have any other specific dependencies.
Thanks to Thomas Achleitner for providing the initial implementation of
this message source!
public void setFileEncodings(java.util.Properties fileEncodings)
Set per-file charsets to use for parsing properties files.
Only applies to classic properties files, not to XML files.
fileEncodings - a Properties with filenames as keys and charset
names as values. Filenames have to match the basename syntax,
with optional locale-specific components: e.g. "WEB-INF/messages"
public void setConcurrentRefresh(boolean concurrentRefresh)
Specify whether to allow for concurrent refresh behavior, i.e. one thread
locked in a refresh attempt for a specific cached properties file whereas
other threads keep returning the old properties for the time being, until
the refresh attempt has completed.
Default is "true": this behavior is new as of Spring Framework 4.1,
minimizing contention between threads. If you prefer the old behavior,
i.e. to fully block on refresh, switch this flag to "false".
Set the ResourceLoader to use for loading bundle properties files.
The default is a DefaultResourceLoader. Will get overridden by the
ApplicationContext if running in a context, as it implements the
ResourceLoaderAware interface. Can be manually overridden when
running outside of an ApplicationContext.
Calculate the filenames for the given bundle basename and Locale,
appending language code, country code, and variant code.
E.g.: basename "messages", Locale "de_AT_oo" -> "messages_de_AT_OO",
Refresh the PropertiesHolder for the given bundle filename.
The holder can be null if not cached before, or a timed-out cache entry
(potentially getting re-validated against the current last-modified timestamp).
filename - the bundle filename (basename + Locale)
propHolder - the current PropertiesHolder for the bundle
filename - the original bundle filename (basename + Locale)
the populated Properties instance
java.io.IOException - if properties loading failed
protected java.util.Properties newProperties()
Template method for creating a plain new Properties instance.
The default implementation simply calls Properties.Properties().
Allows for returning a custom Properties extension in subclasses.
Overriding methods should just instantiate a custom Properties subclass,
with no further initialization or population to be performed at that point.
a plain Properties instance
public void clearCache()
Clear the resource bundle cache.
Subsequent resolve calls will lead to reloading of the properties files.
public void clearCacheIncludingAncestors()
Clear the resource bundle caches of this MessageSource and all its ancestors.