/**

  * - Digitalis Internal Framework v2.0 - (C) 2007, Digitalis Informatica.

  * Distribuicao e Gestao de Informatica, Lda. Estrada de Paco de Arcos num.9 -

  * Piso -1 2780-666 Paco de Arcos Telefone: (351) 21 4408990 Fax: (351) 21

  * 4408999 http://www.digitalis.pt

  */

 package pt.digitalis.dif.utils.logging;

 import pt.digitalis.dif.startup.DIFStartupConfiguration;

 import pt.digitalis.log.ILogWrapper;

 import pt.digitalis.log.LogLevel;

 import pt.digitalis.log.Logger;

 /**

  * This is the framework's base logging aspect. It defines the logging appliance used as a protected member that can be

  * initialized on each sub-aspect constructor, an abstract pointcut - logPoints() - and an abstract logging method that

  * should be implemented by the sub-aspects. Access to the logger should be done through the supplied inspector. Logging

  * of all the Exceptions thrown by the framework or its client applications is also done by this aspect. Exception

  * logging is a top-level concern so it should be on the base aspect. This aspect also supplies some common pointcuts to

  * its children. These include capturing all methods and constructors execution and the exclusion of the logging

  * appliances (such as this aspects and its children as well as the Logger class and its children).

  * 

  * @author Rodrigo Gonçalves <a href="mailto:rgoncalves@digitalis.pt">rgoncalves@digitalis.pt</a>

  * @created 2007/05/22

  */

 public abstract aspect DIFLogAspect {

     /* --- Members --- */

     /** The logger instance */

     static private ILogWrapper logger;

     /* --- General pointcuts --- */

     /** Excluding all development aspects. */

     protected pointcut excludeAllDev() : ! within(pt.digitalis.dif.utils.development.*);

     /** Excluding all startup classes. */

     protected pointcut excludeAllStartup() : ! within(pt.digitalis.dif.startup.DIFStartupConfiguration);

     /**

      * This pointcut excludes all the logging appliances such as this aspect and all its children as well as the

      * Logger class and any eventual children it will might to have.

      */

     protected pointcut excludeLoggingAppliances() : ! within(DIFLogAspect+) && ! within(ILogWrapper+) &&

         excludeAllDev() && excludeAllStartup();

     /**

      * Captures the execution of all methods that are not part of the aspect or the Logger class.

      */

     protected pointcut allMethods() : execution(* pt.digitalis.dif.*..*(..)) && excludeLoggingAppliances();

     /**

      * Captures the execution of all constructors that are not part of the aspect or the Logger class.

      */

     protected pointcut allConstructors() : execution(pt.digitalis.dif.*..*.new(..)) && excludeLoggingAppliances();

     /* --- Methods --- */

     /**

      * Inspector for the defined logger object.

      * 

      * @return the active logger instance 

      */

     static protected ILogWrapper getLogger() {

         // Lazy loading

         if (logger == null) {

             LogLevel level = null;

             // Try to get log level from DiF configurations

             try {

                 level = DIFStartupConfiguration.getLogLevel();

             } catch (Exception e) {

                 // Catch RTEs such as NPEs and do nothing. The code below will make the logging proceed in a transparent and convenient way.

             }

             // If level could not be fetched before, set it to WARN

             if(level == null)

                 level = LogLevel.WARN;

             // Initialize logger with the appropriate level.

             logger = Logger.getLogger("DIF Core", level);

         }

         // Return the active logger instance

         return logger;

     }

 }