org.springframework.context.support

## 类 ReloadableResourceBundleMessageSource

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

- 所有已实现的接口:
    org.springframework.beans.factory.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!

  作者:
    Juergen Hoeller
  另请参阅:
    `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`

- - ### 嵌套类概要

    嵌套类
    限定符和类型 | 类和说明
    --- | ---
    `protected class` | `ReloadableResourceBundleMessageSource.PropertiesHolder` PropertiesHolder for caching.

  - ### 字段概要

    - ### 从类继承的字段 org.springframework.context.support.MessageSourceSupport

      `logger`

  - ### 构造器概要

    构造器
    构造器和说明
    `ReloadableResourceBundleMessageSource()`

  - ### 方法概要

    所有方法 实例方法 具体方法
    限定符和类型 | 方法和说明
    --- | ---
    `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(org.springframework.core.io.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. 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.
    `void` | `setFileEncodings(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.
    `String` | `toString()`

    - ### 从类继承的方法 org.springframework.context.support.AbstractResourceBasedMessageSource

      `addBasenames, getBasenameSet, getCacheMillis, getDefaultEncoding, isFallbackToSystemLocale, setBasename, setBasenames, setCacheMillis, setCacheSeconds, setDefaultEncoding, setFallbackToSystemLocale`

    - ### 从类继承的方法 org.springframework.context.support.AbstractMessageSource

      `getCommonMessages, getDefaultMessage, getDefaultMessage, getMessage, getMessage, getMessage, getMessageFromParent, getMessageInternal, getParentMessageSource, isUseCodeAsDefaultMessage, resolveArguments, setCommonMessages, setParentMessageSource, setUseCodeAsDefaultMessage`

    - ### 从类继承的方法 org.springframework.context.support.MessageSourceSupport

      `createMessageFormat, formatMessage, isAlwaysUseMessageFormat, renderDefaultMessage, setAlwaysUseMessageFormat`

    - ### 从类继承的方法 java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### 构造器详细资料

    - #### ReloadableResourceBundleMessageSource

          public ReloadableResourceBundleMessageSource()

  - ### 方法详细资料

    - #### 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.

      参数:
        `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".
      另请参阅:
        `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".

      从以下版本开始:
        4.1
      另请参阅:
        `AbstractResourceBasedMessageSource.setCacheSeconds(int)`

    - #### setPropertiesPersister

          public void setPropertiesPersister(@Nullable
                                             org.springframework.util.PropertiesPersister propertiesPersister)

      Set the PropertiesPersister to use for parsing properties files.

      The default is a DefaultPropertiesPersister.

      另请参阅:
        `DefaultPropertiesPersister`

    - #### setResourceLoader

          public void setResourceLoader(@Nullable
                                        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.

      指定者:
        `setResourceLoader` 在接口中 `ResourceLoaderAware`
      参数:
        `resourceLoader` - the ResourceLoader object to be used by this object
      另请参阅:
        `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).
      覆盖:
        `resolveCodeWithoutArguments` 在类中 `AbstractMessageSource`
      参数:
        `code` - the code of the message to resolve
        `locale` - the locale to resolve the code for (subclasses are encouraged to support internationalization)
      返回:
        the message String, or `null` if not found
      另请参阅:
        `AbstractMessageSource.resolveCode(java.lang.String, java.util.Locale)`, `MessageFormat`

    - #### resolveCode

          @Nullable
          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.
      指定者:
        `resolveCode` 在类中 `AbstractMessageSource`
      参数:
        `code` - the code of the message to resolve
        `locale` - the locale to resolve the code for (subclasses are encouraged to support internationalization)
      返回:
        the MessageFormat for the message, or `null` if not found
      另请参阅:
        `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.
      参数:
        `basename` - the basename of the bundle
        `locale` - the locale
      返回:
        the List of filenames to check
      另请参阅:
        `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()`.

      参数:
        `basename` - the basename of the bundle
        `locale` - the locale
      返回:
        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.
      参数:
        `filename` - the bundle filename (basename + Locale)
      返回:
        the current PropertiesHolder for the bundle

    - #### refreshProperties

          protected ReloadableResourceBundleMessageSource.PropertiesHolder refreshProperties(String filename,
                                                                                             @Nullable
                                                                                             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).
      参数:
        `filename` - the bundle filename (basename + Locale)
        `propHolder` - the current PropertiesHolder for the bundle

    - #### loadProperties

          protected Properties loadProperties(org.springframework.core.io.Resource resource,
                                              String filename)
                                       throws IOException

      Load the properties from the given resource.
      参数:
        `resource` - the resource to load from
        `filename` - the original bundle filename (basename + Locale)
      返回:
        the populated Properties instance
      抛出:
        `IOException` - if properties loading failed

    - #### newProperties

          protected 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.

      返回:
        a plain Properties instance
      从以下版本开始:
        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.
      另请参阅:
        `clearCache()`

    - #### toString

          public String toString()

      覆盖:
        `toString` 在类中 `Object`