code: public boolean keyspaceExists(DBConn dbConn, String keyspace) {
          try {
              dbConn.getClientSession().describe_keyspace(keyspace);
              return true;
          } catch (Exception e) {
              return false;   // Notfound
          }
      }
docs: Return true if a keyspace with the given name exists. This method can be used with
  any DB connection.
  
  @param dbConn    Database connection to use.
  @param keyspace  Keyspace name.
  @return          True if it exists.