org.springframework.context

## Interface MessageSource

- All Known Subinterfaces:
    ApplicationContext, ConfigurableApplicationContext, ConfigurablePortletApplicationContext, ConfigurableWebApplicationContext, HierarchicalMessageSource, WebApplicationContext
  All Known Implementing Classes:
    AbstractApplicationContext, AbstractMessageSource, AbstractRefreshableApplicationContext, AbstractRefreshableConfigApplicationContext, AbstractRefreshablePortletApplicationContext, AbstractRefreshableWebApplicationContext, AbstractXmlApplicationContext, AnnotationConfigApplicationContext, AnnotationConfigWebApplicationContext, ClassPathXmlApplicationContext, DelegatingMessageSource, FileSystemXmlApplicationContext, GenericApplicationContext, GenericWebApplicationContext, GenericXmlApplicationContext, ReloadableResourceBundleMessageSource, ResourceAdapterApplicationContext, ResourceBundleMessageSource, StaticApplicationContext, StaticMessageSource, StaticPortletApplicationContext, StaticWebApplicationContext, XmlPortletApplicationContext, XmlWebApplicationContext

      public interface MessageSource

  Strategy interface for resolving messages, with support for the parameterization and internationalization of such messages.

  Spring provides two out-of-the-box implementations for production:

  - `ResourceBundleMessageSource`, built on top of the standard `ResourceBundle`
  - `ReloadableResourceBundleMessageSource`, being able to reload message definitions without restarting the VM
  Author:
    Rod Johnson, Juergen Hoeller
  See Also:
    `ResourceBundleMessageSource`, `ReloadableResourceBundleMessageSource`

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `String` | `getMessage(MessageSourceResolvable resolvable, Locale locale)` Try to resolve the message using all the attributes contained within the `MessageSourceResolvable` argument that was passed in.
    `String` | `getMessage(String code, Object[] args, Locale locale)` Try to resolve the message.
    `String` | `getMessage(String code, Object[] args, String defaultMessage, Locale locale)` Try to resolve the message.

- - ### Method Detail

    - #### getMessage

          String getMessage(String code,
                          Object[] args,
                          String defaultMessage,
                          Locale locale)

      Try to resolve the message. Return default message if no message was found.
      Parameters:
        `code` - the code to lookup up, such as 'calculator.noRateSet'. Users of this class are encouraged to base message names on the relevant fully qualified class name, thus avoiding conflict and ensuring maximum clarity.
        `args` - array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message), or `null` if none.
        `defaultMessage` - String to return if the lookup fails
        `locale` - the Locale in which to do the lookup
      Returns:
        the resolved message if the lookup was successful; otherwise the default message passed as a parameter
      See Also:
        `MessageFormat`

    - #### getMessage

          String getMessage(String code,
                          Object[] args,
                          Locale locale)
                            throws NoSuchMessageException

      Try to resolve the message. Treat as an error if the message can't be found.
      Parameters:
        `code` - the code to lookup up, such as 'calculator.noRateSet'
        `args` - Array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message), or `null` if none.
        `locale` - the Locale in which to do the lookup
      Returns:
        the resolved message
      Throws:
        `NoSuchMessageException` - if the message wasn't found
      See Also:
        `MessageFormat`

    - #### getMessage

          String getMessage(MessageSourceResolvable resolvable,
                          Locale locale)
                            throws NoSuchMessageException

      Try to resolve the message using all the attributes contained within the `MessageSourceResolvable` argument that was passed in.

      NOTE: We must throw a `NoSuchMessageException` on this method since at the time of calling this method we aren't able to determine if the `defaultMessage` property of the resolvable is null or not.

      Parameters:
        `resolvable` - value object storing attributes required to properly resolve a message
        `locale` - the Locale in which to do the lookup
      Returns:
        the resolved message
      Throws:
        `NoSuchMessageException` - if the message wasn't found
      See Also:
        `MessageFormat`