code: public Object getIdentifierValue(Identifier id,
                                     boolean ignoreType)
                               throws BadMessageFormatMatchingException {
  
      throw new BadMessageFormatMatchingException(nls.getFormattedMessage("NOT_API_MESSAGE_CWSIF0101"
                                                                         ,new Object[] { getSystemMessageId() }
                                                                         ,"Message selectors are not supported for message " + getSystemMessageId()
                                                                         ));
    }
docs: /*
  Evaluate the message field determined by the given Identifier
  
  Usually the field is either an SI or JMS header field or an SI, JMS or user
  property, but SIB0136 introduces selection using XPATH expressions against
  the message payload.
  
  Javadoc description supplied by MatchSpaceKey interface.
  
  If the message is not a JsJmsMessage message, selectors are not supported.
  If it is a JsJmsMessage. this method will have been overridden.