code: public Collection<FullColumnDescription> getLocalKeyColumnDescriptions()
      {
          if (localKeys == null)
          {
              localKeys = new LinkedList<>();
  
              for (FullColumnDescription col : fullColumnDescriptions.values())
              {
                  if (col.isLocalKeyMember())
                  {
                      this.localKeys.add(col);
                  }
              }
  
              Collections.sort(this.localKeys, LocalKeyComparator.INSTANCE);
          }
  
          return this.localKeys;
      }
docs: Get the collection of Local Key FullColumnDescriptions, in order.
  @return an iterable collection.