code: public static Set<String> getCfNamesByKeySpace(KsDef keySpace)
      {
          Set<String> names = new LinkedHashSet<String>();
  
          for (CfDef cfDef : keySpace.getCf_defs())
          {
              names.add(cfDef.getName());
          }
  
          return names;
      }
docs: Returns set of column family names in specified keySpace.
  @param keySpace - keyspace definition to get column family names from.
  @return Set - column family names