6.2.2. Creating Internationalized Loggers, Messages and Exceptions

Procedure 6.1. Create an Internationalized Log Message Bundle

1. Create an Message Logger interface

   Add a Java interface to your project to contain the log message definitions. Name the interface descriptively for the log messages that will be defined in it.
   The log message interface has the following requirements:
   • It must be annotated with @org.jboss.logging.MessageLogger.
   • It must extend org.jboss.logging.BasicLogger.
   • The interface must define a field of that is a typed logger that implements this interface. Do this with the getMessageLogger() method of org.jboss.logging.Logger.

   package com.company.accounts.loggers;
   
   import org.jboss.logging.BasicLogger;
   import org.jboss.logging.Logger;
   import org.jboss.logging.MessageLogger;
   
   @MessageLogger(projectCode="")
   interface AccountsLogger extends BasicLogger
   {
      AccountsLogger LOGGER = Logger.getMessageLogger(
            AccountsLogger.class,
            AccountsLogger.class.getPackage().getName() );
   }

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2. Add method definitions

   Add a method definition to the interface for each log message. Name each method descriptively for the log message that it represents.
   Each method has the following requirements:
   • The method must return void.
   • It must be annotated with the @org.jboss.logging.LogMessage annotation.
   • It must be annotated with the @org.jboss.logging.Message annotation.
   • The value attribute of @org.jboss.logging.Message contains the default log message. This is the message that is used if no translation is available.

   @LogMessage
   @Message(value = "Customer query failed, Database not available.")
   void customerQueryFailDBClosed();

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   The default log level is INFO.

3. Invoke the methods

   Add the calls to the interface methods in your code where the messages must be logged from. It is not necessary to create implementations of the interfaces, the annotation processor does this for you when the project is compiled.

   AccountsLogger.LOGGER.customerQueryFailDBClosed();

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   The custom loggers are sub-classed from BasicLogger so the logging methods of BasicLogger (debug(), error() etc) can also be used. It is not necessary to create other loggers to log non-internationalized messages.

   AccountsLogger.LOGGER.error("Invalid query syntax.");

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