/** {@inheritDoc} */
  @Nullable
  @Override
  public Map<? extends GridComputeJob, GridNode> map(
      List<GridNode> subgrid, @Nullable GridBiTuple<Set<UUID>, A> arg) throws GridException {
    assert arg != null;
    assert arg.get1() != null;

    start = U.currentTimeMillis();

    boolean debug = debugState(g);

    if (debug) logStart(g.log(), getClass(), start);

    Set<UUID> nodeIds = arg.get1();

    Map<GridComputeJob, GridNode> map = U.newHashMap(nodeIds.size());

    try {
      taskArg = arg.get2();

      for (GridNode node : subgrid) if (nodeIds.contains(node.id())) map.put(job(taskArg), node);

      return map;
    } finally {
      if (debug) logMapped(g.log(), getClass(), map.values());
    }
  }
  /** @throws Exception If failed. */
  public void testInvalidateFlag() throws Exception {
    GridEx g0 = grid(0);

    GridCache<String, String> cache = g0.cache(PARTITIONED_CACHE_NAME);

    String key = null;

    for (int i = 0; i < 10_000; i++) {
      if (!cache.affinity().isPrimaryOrBackup(g0.localNode(), String.valueOf(i))) {
        key = String.valueOf(i);

        break;
      }
    }

    assertNotNull(key);

    cache.put(key, key); // Create entry in near cache, it is invalidated if INVALIDATE flag is set.

    assertNotNull(cache.peek(key));

    GridClientData d = client.data(PARTITIONED_CACHE_NAME);

    d.flagsOn(GridClientCacheFlag.INVALIDATE).put(key, "zzz");

    for (Grid g : G.allGrids()) {
      cache = g.cache(PARTITIONED_CACHE_NAME);

      if (cache.affinity().isPrimaryOrBackup(g.localNode(), key))
        assertEquals("zzz", cache.peek(key));
      else assertNull(cache.peek(key));
    }
  }
 /** {@inheritDoc} */
 @Nullable
 @Override
 public final R reduce(List<GridComputeJobResult> results) throws GridException {
   try {
     return reduce0(results);
   } finally {
     if (debugState(g)) logFinish(g.log(), getClass(), start);
   }
 }