Package org.grails.spring.context.support

Class ReloadableResourceBundleMessageSource

  • All Implemented Interfaces:
    org.springframework.beans.factory.Aware, org.springframework.context.HierarchicalMessageSource, org.springframework.context.MessageSource, org.springframework.context.ResourceLoaderAware
    Direct Known Subclasses:
    PluginAwareResourceBundleMessageSource
    public class ReloadableResourceBundleMessageSource
extends org.springframework.context.support.AbstractMessageSource
implements org.springframework.context.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.

    In contrast to ResourceBundleMessageSource, this class supports reloading of properties files through the "cacheSeconds" setting, and also through programmatically clearing the properties cache. Since application servers typically cache all files loaded from the classpath, it is necessary to store resources somewhere else (for example, in the "WEB-INF" directory of a web app). Otherwise changes of files in the classpath will not be reflected in the application.

    Note that the base names 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) will not work in this case.

    This MessageSource implementation is usually slightly faster than ResourceBundleMessageSource, which builds on ResourceBundle - in the default mode, i.e. when caching forever. With "cacheSeconds" set to 1, message lookup takes about twice as long - with the benefit that changes in individual properties files are detected with a maximum delay of 1 second. Higher "cacheSeconds" values usually do not make a significant difference.

    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!

    See Also:
    setCacheSeconds(int), setBasenames(java.lang.String...), setDefaultEncoding(java.lang.String), setFileEncodings(java.util.Properties), setPropertiesPersister(org.springframework.util.PropertiesPersister), setResourceLoader(org.springframework.core.io.ResourceLoader), DefaultPropertiesPersister, DefaultResourceLoader, ResourceBundleMessageSource, ResourceBundle

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected long cacheMillis  
      protected long fileCacheMillis  

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

        logger

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected java.util.List<Pair<java.lang.String,​org.springframework.core.io.Resource>> calculateAllFilenames​(java.lang.String basename, java.util.Locale locale)
      Calculate all filenames for the given bundle basename and Locale.
      protected java.util.List<java.lang.String> calculateFilenamesForLocale​(java.lang.String basename, java.util.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.
      java.util.Set<java.lang.String> getBundleCodes​(java.util.Locale locale, java.lang.String... basenames)
      Retrieves all codes from one or multiple basenames
      protected ReloadableResourceBundleMessageSource.PropertiesHolder getMergedProperties​(java.util.Locale locale)
      Get a PropertiesHolder that contains the actually visible properties for a Locale, after merging all specified resource bundles.
      protected ReloadableResourceBundleMessageSource.PropertiesHolder getProperties​(java.lang.String filename, org.springframework.core.io.Resource resource)
      Get a PropertiesHolder for the given filename, either from the cache or freshly loaded.
      protected java.util.List<java.lang.String> getValidBasenames​(java.lang.String[] basenames)  
      protected java.util.Properties loadProperties​(org.springframework.core.io.Resource resource, java.lang.String filename)
      Load the properties from the given resource.
      protected org.springframework.core.io.Resource locateResource​(java.lang.String filename)  
      protected org.springframework.core.io.Resource locateResourceWithoutCache​(java.lang.String filename)  
      protected java.text.MessageFormat resolveCode​(java.lang.String code, java.util.Locale locale)
      Resolves the given message code as key in the retrieved bundle files, using a cached MessageFormat instance per message code.
      protected java.lang.String resolveCodeWithoutArguments​(java.lang.String code, java.util.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 setBasename​(java.lang.String basename)
      Set a single basename, following the basic ResourceBundle convention of not specifying file extension or language codes, but in contrast to ResourceBundleMessageSource referring to a Spring resource location: e.g.
      void setBasenames​(java.lang.String... basenames)
      Set an array of basenames, each following the basic ResourceBundle convention of not specifying file extension or language codes, but in contrast to ResourceBundleMessageSource referring to a Spring resource location: e.g.
      void setCacheSeconds​(int cacheSeconds)
      Set the number of seconds to cache the list of matching properties files.
      void setDefaultEncoding​(java.lang.String defaultEncoding)
      Set the default charset to use for parsing properties files.
      void setFallbackToSystemLocale​(boolean fallbackToSystemLocale)
      Set whether to fall back to the system Locale if no files for a specific Locale have been found.
      void setFileCacheSeconds​(int fileCacheSeconds)
      Set the number of seconds to cache loaded properties files.
      void setFileEncodings​(java.util.Properties fileEncodings)
      Set per-file charsets to use for parsing properties files.
      void setPropertiesPersister​(org.springframework.util.PropertiesPersister propertiesPersister)
      Set the PropertiesPersister to use for parsing properties files.
      void setResourceLoader​(org.springframework.core.io.ResourceLoader resourceLoader)
      Set the ResourceLoader to use for loading bundle properties files.
      java.lang.String toString()  

      • 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

    • Field Detail

      • cacheMillis

        protected long cacheMillis

      • fileCacheMillis

        protected long fileCacheMillis

    • Constructor Detail

      • ReloadableResourceBundleMessageSource

        public ReloadableResourceBundleMessageSource()

    • Method Detail

      • setBasename

        public void setBasename​(java.lang.String basename)
        Set a single basename, following the basic ResourceBundle convention of not specifying file extension or language codes, but in contrast to ResourceBundleMessageSource referring to a Spring resource location: e.g. "WEB-INF/messages" for "WEB-INF/messages.properties", "WEB-INF/messages_en.properties", etc.

        XML properties files are also supported: .g. "WEB-INF/messages" will find and load "WEB-INF/messages.xml", "WEB-INF/messages_en.xml", etc as well.

        Parameters:
        basename - the single basename
        See Also:
        setBasenames(java.lang.String...), ResourceEditor, ResourceBundle

      • getBundleCodes

        public java.util.Set<java.lang.String> getBundleCodes​(java.util.Locale locale,
                                                      java.lang.String... basenames)
        Retrieves all codes from one or multiple basenames
        Parameters:
        locale - the locale
        basenames - the basenames of the bundle
        Returns:
        a list with all codes from valid registered bundles

      • getValidBasenames

        protected java.util.List<java.lang.String> getValidBasenames​(java.lang.String[] basenames)

      • setBasenames

        public void setBasenames​(java.lang.String... basenames)
        Set an array of basenames, each following the basic ResourceBundle convention of not specifying file extension or language codes, but in contrast to ResourceBundleMessageSource referring to a Spring resource location: e.g. "WEB-INF/messages" for "WEB-INF/messages.properties", "WEB-INF/messages_en.properties", etc.

        XML properties files are also supported: .g. "WEB-INF/messages" will find and load "WEB-INF/messages.xml", "WEB-INF/messages_en.xml", etc as well.

        The associated resource bundles will be checked sequentially when resolving a message code. Note that message definitions in a previous resource bundle will override ones in a later bundle, due to the sequential lookup.

        Parameters:
        basenames - an array of basenames
        See Also:
        setBasename(java.lang.String), ResourceBundle

      • setDefaultEncoding

        public void setDefaultEncoding​(java.lang.String defaultEncoding)
        Set the default charset to use for parsing properties files. Used if no file-specific charset is specified for a file.

        Default is none, using the java.util.Properties default encoding: ISO-8859-1.

        Only applies to classic properties files, not to XML files.

        Parameters:
        defaultEncoding - the default charset
        See Also:
        setFileEncodings(java.util.Properties), PropertiesPersister.load(java.util.Properties, java.io.InputStream)

      • setFileEncodings

        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.

        Parameters:
        fileEncodings - Properties with filenames as keys and charset names as values. Filenames have to match the basename syntax, with optional locale-specific appendices: e.g. "WEB-INF/messages" or "WEB-INF/messages_en".
        See Also:
        setBasenames(java.lang.String...), PropertiesPersister.load(java.util.Properties, java.io.InputStream)

      • setFallbackToSystemLocale

        public void setFallbackToSystemLocale​(boolean fallbackToSystemLocale)
        Set whether to fall back to the system Locale if no files for a specific Locale have been found. Default is "true"; if this is turned off, the only fallback will be the default file (e.g. "messages.properties" for basename "messages").

        Falling back to the system Locale is the default behavior of java.util.ResourceBundle. However, this is often not desirable in an application server environment, where the system Locale is not relevant to the application at all: Set this flag to "false" in such a scenario.

      • setCacheSeconds

        public void setCacheSeconds​(int cacheSeconds)
        Set the number of seconds to cache the list of matching properties files.
        • Default is "-1", indicating to cache forever (just like java.util.ResourceBundle).
        • A positive number will cache the list of matching properties files for the given number of seconds. This is essentially the interval between refresh checks.
        • A value of "0" will attemp to list the matching properties files on every message access. Do not use this in a production environment!

      • setFileCacheSeconds

        public void setFileCacheSeconds​(int fileCacheSeconds)
        Set the number of seconds to cache loaded properties files.
        • Default value is the same value as cacheSeconds
        • A positive number will cache loaded properties files for the given number of seconds. This is essentially the interval between refresh checks. Note that a refresh attempt will first check the last-modified timestamp of the file before actually reloading it; so if files don't change, this interval can be set rather low, as refresh attempts will not actually reload.
        • A value of "0" will check the last-modified timestamp of the file on every message access. Do not use this in a production environment!

      • setPropertiesPersister

        public void setPropertiesPersister​(org.springframework.util.PropertiesPersister propertiesPersister)
        Set the PropertiesPersister to use for parsing properties files.

        The default is a DefaultPropertiesPersister.

        See Also:
        DefaultPropertiesPersister

      • setResourceLoader

        public void setResourceLoader​(org.springframework.core.io.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 org.springframework.context.ResourceLoaderAware
        See Also:
        DefaultResourceLoader, ResourceLoaderAware

      • resolveCodeWithoutArguments

        protected java.lang.String resolveCodeWithoutArguments​(java.lang.String code,
                                                       java.util.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 org.springframework.context.support.AbstractMessageSource

      • resolveCode

        protected java.text.MessageFormat resolveCode​(java.lang.String code,
                                              java.util.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 org.springframework.context.support.AbstractMessageSource

      • getMergedProperties

        protected ReloadableResourceBundleMessageSource.PropertiesHolder getMergedProperties​(java.util.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 java.util.List<Pair<java.lang.String,​org.springframework.core.io.Resource>> calculateAllFilenames​(java.lang.String basename,
                                                                                                                  java.util.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:
        setFallbackToSystemLocale(boolean), calculateFilenamesForLocale(java.lang.String, java.util.Locale)

      • calculateFilenamesForLocale

        protected java.util.List<java.lang.String> calculateFilenamesForLocale​(java.lang.String basename,
                                                                       java.util.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​(java.lang.String filename,
                                                                               org.springframework.core.io.Resource resource)
        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

      • loadProperties

        protected java.util.Properties loadProperties​(org.springframework.core.io.Resource resource,
                                              java.lang.String filename)
                                       throws java.io.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:
        java.io.IOException - if properties loading failed

      • 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 java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • locateResource

        protected org.springframework.core.io.Resource locateResource​(java.lang.String filename)

      • locateResourceWithoutCache

        protected org.springframework.core.io.Resource locateResourceWithoutCache​(java.lang.String filename)