Ajout d'une méthode can_handle dans SitePlugin.

Cette méthode soulève une exception. Elle DOIT être implémentée par les
classes filles.

lib/playbot.rb

@@ -3,9 +3,8 @@ require 'net/yail/irc_bot'
 
 require 'site_plugin'
 
-#
+# --
 # Add plugins folder to LOAD_PATH and subsequently require all plugins.
-#
 dir = '../plugins'
 $LOAD_PATH << dir
 Dir[File.join(dir, '*.rb')].each {|file| require File.basename(file) }

lib/site_plugin.rb

+# Implement a plugin system.
+#
+# Each plugin have to inherite from this class and implement a can_handle?(site) method.
 class SitePlugin
     @@repository = []
 
@@ -9,7 +12,13 @@ class SitePlugin
         @@repository << target
     end
 
+    # Return the plugin that can handle a given site.
     def self.for_site(site)
         @@repository.find {|handler| handler.can_handle? site }
     end
+
+    # A place holder method. This method *must* be implemented in the subclasses.
+    def can_handle?(site)
+        raise "Method not implemented !"
+    end
 end