/** @throws Exception If failed. */ public void testTopologyListener() throws Exception { final Collection<UUID> added = new ArrayList<>(1); final Collection<UUID> rmvd = new ArrayList<>(1); final CountDownLatch addedLatch = new CountDownLatch(1); final CountDownLatch rmvLatch = new CountDownLatch(1); assertEquals(NODES_CNT, client.compute().refreshTopology(false, false).size()); GridClientTopologyListener lsnr = new GridClientTopologyListener() { @Override public void onNodeAdded(GridClientNode node) { added.add(node.nodeId()); addedLatch.countDown(); } @Override public void onNodeRemoved(GridClientNode node) { rmvd.add(node.nodeId()); rmvLatch.countDown(); } }; client.addTopologyListener(lsnr); try { Grid g = startGrid(NODES_CNT + 1); UUID id = g.localNode().id(); assertTrue(addedLatch.await(2 * TOP_REFRESH_FREQ, MILLISECONDS)); assertEquals(1, added.size()); assertEquals(id, F.first(added)); stopGrid(NODES_CNT + 1); assertTrue(rmvLatch.await(2 * TOP_REFRESH_FREQ, MILLISECONDS)); assertEquals(1, rmvd.size()); assertEquals(id, F.first(rmvd)); } finally { client.removeTopologyListener(lsnr); stopGrid(NODES_CNT + 1); } }