code: @Deprecated
    public DatanodeDescriptor getDatanodeByName(String name) {
      if (name == null) {
        return null;
      }
      int colon = name.indexOf(":");
      String host;
      if (colon < 0) {
        host = name;
      } else {
        host = name.substring(0, colon);
      }
      hostmapLock.readLock().lock();
      try {
        DatanodeDescriptor[] nodes = map.get(host);
        // no entry
        if (nodes == null) {
          return null;
        }
        for (DatanodeDescriptor containedNode : nodes) {
          if (name.equals(containedNode.getName())) {
            return containedNode;
          }
        }
        return null;
      } finally {
        hostmapLock.readLock().unlock();
      }
    }
docs: Find data node by its name.
  
  @deprecated use {@link #getDataNodeByIpPort(String)}
  @return DatanodeDescriptor if found or null otherwise