Class<? extends LabFactory> getFactoryClass()
  {
	final String className = getProperty(PROPERTY_CLASS);
	try
	{
	  LOGGER.trace("Loading LabFactory class {}", className);
	  return Class.forName(className).asSubclass(LabFactory.class);
	}
	catch (final ClassNotFoundException e)
	{
	  throw new IllegalStateException("Factory class not found " + className, e);
	}
  }