public int compare(final ReadTransformer r1, final ReadTransformer r2) { if (r1.getOrderingConstraint() == r2.getOrderingConstraint()) return 0; return (r1.getOrderingConstraint() == OrderingConstraint.MUST_BE_FIRST || r2.getOrderingConstraint() == OrderingConstraint.MUST_BE_LAST) ? -1 : 1; }