code: public void pluginAppears( PluginInterface pi ) {
  		if( pi != null ) {
  			this.logger.info( "Plugin '" + pi.getPluginName() + "' is now available in Roboconf's agent." );
  			this.plugins.add( pi );
  			listPlugins();
  		}
  	}
docs: This method is invoked by iPojo every time a new plug-in appears.
  @param pi the appearing plugin.