package com.aragost.javahg.log;

 import com.aragost.javahg.internals.ServiceLoader;

 import com.google.common.base.Strings;

 /**

  * Factory class to retrieve a {@link Logger} instance. The LoggerFactory 

  * searches a implementation with the use of {@link ServiceLoader}, if no

  * implementation could be found it uses the default implementation 

  * {@link JULLoggerFactory}.

  */

 public abstract class LoggerFactory {

     private static LoggerFactory instance;

     static {

         String loggerFactoryName = System.getProperty( LoggerFactory.class.getName() );

         try 

         {

             if ( ! Strings.isNullOrEmpty(loggerFactoryName) ){

                 instance = (LoggerFactory) Class.forName(loggerFactoryName).newInstance();

             } else {

                 instance = ServiceLoader.loadService(LoggerFactory.class);

             }

         } 

         catch (Exception ex)

         {

           // do nothing

         }

         if ( instance == null ){

             instance = new JULLoggerFactory();

         }

     }

     /**

      * Return a logger for the class

      * 

      * @param cls

      * @return

      */

     public static Logger getLogger(Class<?> cls) {

         return instance.getLoggerInstance(cls);

     }

     protected abstract Logger getLoggerInstance(Class<?> cls);

 }