else if (sortOrder.equals(GROUP_BY_BUG_CATEGORY)) return bugInstanceByCategoryComparator;
	private Comparator<BugInstance> getBugInstanceComparator(String sortOrder) {		if (sortOrder.equals(GROUP_BY_CLASS))			return bugInstanceByClassComparator;		else if (sortOrder.equals(GROUP_BY_PACKAGE))			return bugInstanceByPackageComparator;		else if (sortOrder.equals(GROUP_BY_BUG_TYPE))			return bugInstanceByTypeComparator;		else			throw new IllegalArgumentException("Bad sort order: " + sortOrder);	}