6.2.2.3. Create Internationalized Exceptions

Procedure 6.3. Create and use Internationalized Exceptions

1. Add JBoss Logging Tools configuration

   Add the required project configuration to support JBoss Logging Tools. Refer to Section 6.2.6.1, “JBoss Logging Tools Maven Configuration”

2. Create an interface for the exceptions

   JBoss Logging Tools defines internationalized exceptions in interfaces. Name each interface descriptively for the exceptions that will be defined in it.
   The interface has the following requirements:
   • It must be declared as public.
   • It must be annotated with @org.jboss.logging.MessageBundle.
   • The interface must define a field that is a message bundle of the same type as the interface.

   @MessageBundle(projectCode="")
   public interface ExceptionBundle 
   {
      ExceptionBundle EXCEPTIONS = Messages.getBundle(ExceptionBundle.class);
   }
   

3. Add method definitions

   Add a method definition to the interface for each exception. Name each method descriptively for the exception that it represents.
   Each method has the following requirements:
   • It must return an object of type Exception or a sub-type of Exception.
   • It must be annotated with the @org.jboss.logging.Message annotation.
   • The value attribute of @org.jboss.logging.Message must be set to the default exception message. This is the message that is used if no translation is available.
   • If the exception being returned has a constructor that requires parameters in addition to a message string, then those parameters must be supplied in the method definition using the @Param annotation. The parameters must be the same type and order as the constructor.

   @Message(value = "The config file could not be opened.")
   IOException configFileAccessError();
   
   @Message(id = 13230, value = "Date string '%s' was invalid.")
   ParseException dateWasInvalid(String dateString, @Param int errorOffset);

4. Invoke methods

   Invoke the interface methods in your code where you need to obtain one of the exceptions. The methods do not throw the exceptions, they return the exception object which you can then throw.

   try 
   {
      propsInFile=new File(configname);
      props.load(new FileInputStream(propsInFile));
   }
   catch(IOException ioex) //in case props file does not exist
   {
      throw ExceptionBundle.EXCEPTIONS.configFileAccessError(); 
   }