MessageSourceAware class abstract interface

🫘 Interface for components that need access to a MessageSource.

The MessageSourceAware interface enables components to access internationalization (i18n) and localization services for resolving parameterized messages in different locales.

Key Features:

• Message Resolution: Resolve message codes to localized strings
• Parameter Support: Handle parameterized messages with placeholders
• Locale Awareness: Support multiple languages and regions
• Fallback Handling: Graceful degradation when messages are missing

Framework Integration:

• Called during component initialization when a MessageSource is available
• The MessageSource may be null if no message source is configured
• Typically configured via the ApplicationContext's message source

Example Usage:

@Component
class InternationalizedService implements MessageSourceAware {
  MessageSource? _messageSource;

  @override
  void setMessageSource(MessageSource? messageSource) {
    _messageSource = messageSource;
  }

  String getWelcomeMessage(String username, Locale locale) {
    return _messageSource?.getMessage(
      'welcome.message',
      args: [username],
      locale: locale,
      defaultMessage: 'Welcome, $username!'
    ) ?? 'Welcome, $username!';
  }

  String getErrorMessage(String errorCode, Locale locale) {
    return _messageSource?.getMessage(
      'error.$errorCode',
      locale: locale,
      defaultMessage: 'An error occurred.'
    ) ?? 'An error occurred.';
  }
}

Best Practices:

• Always provide sensible default messages
• Handle null MessageSource gracefully in production code
• Use consistent message code naming conventions
• Consider locale fallback chains for better user experience

See also:

• MessageSource for the message source interface
• ApplicationContextAware for broader context access