@Override public boolean removeVertex (Inter inter) { if (!inter.isRemoved()) { logger.error("Do not use removeVertex() directly. Use inter.remove() instead."); throw new IllegalStateException("Do not use removeVertex() directly"); } // Remove from inter index. TODO: is this a good idea? system.getSheet().getInterIndex().remove(inter); if (inter.isVip()) { logger.info("VIP removeVertex {}", inter); } return super.removeVertex(inter); }