Factory factory = new Factory(xmlFile, xmlRulesFile);
if ( factory == null )
throw new SimulationException( "No pudo crearse la factor�a para " +
"levantar los robots." );
Robot robot = (Robot)factory.digest();
if (robot == null)
throw new SimulationException( "No pudo cargarse el robot." );
simulation.addRobot(robot);
}