/**
   * Helper function to get value from map.
   *
   * @param map Map to take value from.
   * @param key Key to search in map.
   * @param ifNull Default value if {@code null} was returned by map.
   * @param <K> Key type.
   * @param <V> Value type.
   * @return Value from map or default value if map return {@code null}.
   */
  public static <K, V> V getOrElse(Map<K, V> map, K key, V ifNull) {
    assert map != null;

    V res = map.get(key);

    return res != null ? res : ifNull;
  }
 /** {@inheritDoc} */
 @Override
 public boolean isCacheTopologyValid(GridCacheContext cctx) {
   return cctx.config().getTopologyValidator() != null && cacheValidRes.containsKey(cctx.cacheId())
       ? cacheValidRes.get(cctx.cacheId())
       : true;
 }