### Question:
PrepareContractionHierarchies extends AbstractAlgoPreparation { public PrepareContractionHierarchies useFixedNodeOrdering(NodeOrderingProvider nodeOrderingProvider) { if (nodeOrderingProvider.getNumNodes() != prepareGraph.getNodes()) { throw new IllegalArgumentException( "contraction order size (" + nodeOrderingProvider.getNumNodes() + ")" + " must be equal to number of nodes in graph (" + prepareGraph.getNodes() + ")."); } this.nodeOrderingProvider = nodeOrderingProvider; return this; } private  PrepareContractionHierarchies(GraphHopperStorage ghStorage, CHProfile chProfile); static PrepareContractionHierarchies fromGraphHopperStorage(GraphHopperStorage ghStorage, CHProfile chProfile); PrepareContractionHierarchies setParams(PMap pMap); PrepareContractionHierarchies useFixedNodeOrdering(NodeOrderingProvider nodeOrderingProvider); @Override void doSpecificWork(); boolean isEdgeBased(); long getDijkstraCount(); long getShortcuts(); double getLazyTime(); double getPeriodTime(); double getNeighborTime(); Weighting getWeighting(); CHProfile getCHProfile(); long getTotalPrepareTime(); @Override String toString(); RoutingAlgorithmFactory getRoutingAlgorithmFactory();  }### Answer:
@Test public void testDisconnects() { g.edge(8, 3, 1, false); g.edge(3, 6, 1, false); g.edge(6, 1, 1, false); g.edge(1, 5, 1, false); g.edge(4, 0, 1, false); g.edge(0, 6, 1, false); g.edge(6, 2, 1, false); g.edge(2, 7, 1, false); g.freeze(); PrepareContractionHierarchies prepare = createPrepareContractionHierarchies(g) .useFixedNodeOrdering(new NodeOrderingProvider() { @Override public int getNodeIdForLevel(int level) { return level; } @Override public int getNumNodes() { return g.getNodes(); } }); prepare.doWork(); CHEdgeExplorer explorer = lg.createEdgeExplorer(); assertEquals(buildSet(7, 8, 0, 1, 2, 3), GHUtility.getNeighbors(explorer.setBaseNode(6))); assertEquals(buildSet(6, 0), GHUtility.getNeighbors(explorer.setBaseNode(4))); assertEquals(buildSet(6, 1), GHUtility.getNeighbors(explorer.setBaseNode(5))); assertEquals(buildSet(8, 2), GHUtility.getNeighbors(explorer.setBaseNode(7))); assertEquals(buildSet(3), GHUtility.getNeighbors(explorer.setBaseNode(8))); }