java.lang.Object
- org.springframework.context.support.MessageSourceSupport
- - org.springframework.context.support.AbstractMessageSource
  - - org.springframework.context.support.AbstractResourceBasedMessageSource
    - - org.springframework.context.support.ReloadableResourceBundleMessageSource

All Implemented Interfaces:
Aware, HierarchicalMessageSource, MessageSource, ResourceLoaderAware
```
public class ReloadableResourceBundleMessageSource
extends AbstractResourceBasedMessageSource
implements ResourceLoaderAware
```
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!
Author:
Juergen Hoeller
See Also:
AbstractResourceBasedMessageSource.setCacheSeconds(int), AbstractResourceBasedMessageSource.setBasenames(java.lang.String...), AbstractResourceBasedMessageSource.setDefaultEncoding(java.lang.String), setFileEncodings(java.util.Properties), setPropertiesPersister(org.springframework.util.PropertiesPersister), setResourceLoader(org.springframework.core.io.ResourceLoader), DefaultPropertiesPersister, DefaultResourceLoader, ResourceBundleMessageSource, ResourceBundle

Nested Class Summary
Nested Classes
Modifier and Type Class Description
protected class ReloadableResourceBundleMessageSource.PropertiesHolder
PropertiesHolder for caching.

Field Summary
- Fields inherited from class org.springframework.context.support.MessageSourceSupport
  logger

Constructor Summary
Constructors
Constructor Description
ReloadableResourceBundleMessageSource()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected List<String>`	`calculateAllFilenames(String basename, Locale locale)`	Calculate all filenames for the given bundle basename and Locale.
`protected List<String>`	`calculateFilenamesForLocale(String basename, Locale locale)`	Calculate the filenames for the given bundle basename and Locale, appending language code, country code, and variant code.
`void`	`clearCache()`	Clear the resource bundle cache.
`void`	`clearCacheIncludingAncestors()`	Clear the resource bundle caches of this MessageSource and all its ancestors.
`protected ReloadableResourceBundleMessageSource.PropertiesHolder`	`getMergedProperties(Locale locale)`	Get a PropertiesHolder that contains the actually visible properties for a Locale, after merging all specified resource bundles.
`protected ReloadableResourceBundleMessageSource.PropertiesHolder`	`getProperties(String filename)`	Get a PropertiesHolder for the given filename, either from the cache or freshly loaded.
`protected Properties`	`loadProperties(Resource resource, String filename)`	Load the properties from the given resource.
`protected Properties`	`newProperties()`	Template method for creating a plain new `Properties` instance.
`protected ReloadableResourceBundleMessageSource.PropertiesHolder`	`refreshProperties(String filename, ReloadableResourceBundleMessageSource.PropertiesHolder propHolder)`	Refresh the PropertiesHolder for the given bundle filename.
`protected MessageFormat`	`resolveCode(String code, Locale locale)`	Resolves the given message code as key in the retrieved bundle files, using a cached MessageFormat instance per message code.
`protected String`	`resolveCodeWithoutArguments(String code, Locale locale)`	Resolves the given message code as key in the retrieved bundle files, returning the value found in the bundle as-is (without MessageFormat parsing).
`void`	`setConcurrentRefresh(boolean concurrentRefresh)`	Specify whether to allow for concurrent refresh behavior, i.e.
`void`	`setFileEncodings(Properties fileEncodings)`	Set per-file charsets to use for parsing properties files.
`void`	`setPropertiesPersister(PropertiesPersister propertiesPersister)`	Set the PropertiesPersister to use for parsing properties files.
`void`	`setResourceLoader(ResourceLoader resourceLoader)`	Set the ResourceLoader to use for loading bundle properties files.
`String`	`toString()`

Methods inherited from class org.springframework.context.support.AbstractResourceBasedMessageSource
addBasenames, getBasenameSet, getCacheMillis, getDefaultEncoding, isFallbackToSystemLocale, setBasename, setBasenames, setCacheMillis, setCacheSeconds, setDefaultEncoding, setFallbackToSystemLocale

Methods inherited from class org.springframework.context.support.AbstractMessageSource
getCommonMessages, getDefaultMessage, getDefaultMessage, getMessage, getMessage, getMessage, getMessageFromParent, getMessageInternal, getParentMessageSource, isUseCodeAsDefaultMessage, resolveArguments, setCommonMessages, setParentMessageSource, setUseCodeAsDefaultMessage

Methods inherited from class org.springframework.context.support.MessageSourceSupport
createMessageFormat, formatMessage, isAlwaysUseMessageFormat, renderDefaultMessage, setAlwaysUseMessageFormat

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - ReloadableResourceBundleMessageSource
```
public ReloadableResourceBundleMessageSource()
```
- Method Detail
  - setFileEncodings
```
public void setFileEncodings(Properties fileEncodings)
```
    Set per-file charsets to use for parsing properties files.
    Only applies to classic properties files, not to XML files.
    Parameters:
    fileEncodings - 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" or "WEB-INF/messages_en".
    See Also:
    AbstractResourceBasedMessageSource.setBasenames(java.lang.String...), PropertiesPersister.load(java.util.Properties, java.io.InputStream)
  - setConcurrentRefresh
```
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".
    Since:
    4.1
    See Also:
    AbstractResourceBasedMessageSource.setCacheSeconds(int)
  - setPropertiesPersister
```
public void setPropertiesPersister(PropertiesPersister propertiesPersister)
```
    Set the PropertiesPersister to use for parsing properties files.
    The default is a DefaultPropertiesPersister.
    See Also:
    DefaultPropertiesPersister
  - setResourceLoader
```
public void setResourceLoader(ResourceLoader resourceLoader)
```
    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.
    Specified by:
    setResourceLoader in interface ResourceLoaderAware
    Parameters:
    resourceLoader - the ResourceLoader object to be used by this object
    See Also:
    DefaultResourceLoader, ResourceLoaderAware
  - resolveCodeWithoutArguments
```
protected String resolveCodeWithoutArguments(String code,
                                             Locale locale)
```
    Resolves the given message code as key in the retrieved bundle files, returning the value found in the bundle as-is (without MessageFormat parsing).
    Overrides:
    resolveCodeWithoutArguments in class AbstractMessageSource
    Parameters:
    code - the code of the message to resolve
    locale - the locale to resolve the code for (subclasses are encouraged to support internationalization)
    Returns:
    the message String, or null if not found
    See Also:
    AbstractMessageSource.resolveCode(java.lang.String, java.util.Locale), MessageFormat
  - resolveCode
```
protected MessageFormat resolveCode(String code,
                                    Locale locale)
```
    Resolves the given message code as key in the retrieved bundle files, using a cached MessageFormat instance per message code.
    Specified by:
    resolveCode in class AbstractMessageSource
    Parameters:
    code - the code of the message to resolve
    locale - the locale to resolve the code for (subclasses are encouraged to support internationalization)
    Returns:
    the MessageFormat for the message, or null if not found
    See Also:
    AbstractMessageSource.resolveCodeWithoutArguments(String, java.util.Locale)
  - getMergedProperties
```
protected ReloadableResourceBundleMessageSource.PropertiesHolder getMergedProperties(Locale locale)
```
    Get a PropertiesHolder that contains the actually visible properties for a Locale, after merging all specified resource bundles. Either fetches the holder from the cache or freshly loads it.
    Only used when caching resource bundle contents forever, i.e. with cacheSeconds < 0. Therefore, merged properties are always cached forever.
  - calculateAllFilenames
```
protected List<String> calculateAllFilenames(String basename,
                                             Locale locale)
```
    Calculate all filenames for the given bundle basename and Locale. Will calculate filenames for the given Locale, the system Locale (if applicable), and the default file.
    Parameters:
    basename - the basename of the bundle
    locale - the locale
    Returns:
    the List of filenames to check
    See Also:
    AbstractResourceBasedMessageSource.setFallbackToSystemLocale(boolean), calculateFilenamesForLocale(java.lang.String, java.util.Locale)
  - calculateFilenamesForLocale
```
protected List<String> calculateFilenamesForLocale(String basename,
                                                   Locale locale)
```
    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", "messages_de_AT", "messages_de".
    Follows the rules defined by Locale.toString().
    Parameters:
    basename - the basename of the bundle
    locale - the locale
    Returns:
    the List of filenames to check
  - getProperties
```
protected ReloadableResourceBundleMessageSource.PropertiesHolder getProperties(String filename)
```
    Get a PropertiesHolder for the given filename, either from the cache or freshly loaded.
    Parameters:
    filename - the bundle filename (basename + Locale)
    Returns:
    the current PropertiesHolder for the bundle
  - refreshProperties
```
protected ReloadableResourceBundleMessageSource.PropertiesHolder refreshProperties(String filename,
                                                                                   ReloadableResourceBundleMessageSource.PropertiesHolder propHolder)
```
    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).
    Parameters:
    filename - the bundle filename (basename + Locale)
    propHolder - the current PropertiesHolder for the bundle
  - loadProperties
```
protected Properties loadProperties(Resource resource,
                                    String filename)
                             throws IOException
```
    Load the properties from the given resource.
    Parameters:
    resource - the resource to load from
    filename - the original bundle filename (basename + Locale)
    Returns:
    the populated Properties instance
    Throws:
    IOException - if properties loading failed
  - newProperties
```
protected Properties newProperties()
```
    Template method for creating a plain new Properties instance. The default implementation simply calls 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.
    Returns:
    a plain Properties instance
    Since:
    4.2
  - clearCache
```
public void clearCache()
```
    Clear the resource bundle cache. Subsequent resolve calls will lead to reloading of the properties files.
  - clearCacheIncludingAncestors
```
public void clearCacheIncludingAncestors()
```
    Clear the resource bundle caches of this MessageSource and all its ancestors.
    See Also:
    clearCache()
  - toString
```
public String toString()
```
    Overrides:
    toString in class Object

Class ReloadableResourceBundleMessageSource

Nested Class Summary

Field Summary

Fields inherited from class org.springframework.context.support.MessageSourceSupport

Constructor Summary

Method Summary

Methods inherited from class org.springframework.context.support.AbstractResourceBasedMessageSource

Methods inherited from class org.springframework.context.support.AbstractMessageSource

Methods inherited from class org.springframework.context.support.MessageSourceSupport

Methods inherited from class java.lang.Object

Constructor Detail

ReloadableResourceBundleMessageSource

Method Detail

setFileEncodings

setConcurrentRefresh

setPropertiesPersister

setResourceLoader

resolveCodeWithoutArguments

resolveCode

getMergedProperties

calculateAllFilenames

calculateFilenamesForLocale

getProperties

refreshProperties

loadProperties

newProperties

clearCache

clearCacheIncludingAncestors

toString