code: public String toFtpCmdArgument() {
  	char comma = ',';
  	boolean first = true;
  	StringBuffer result = new StringBuffer();
  	for (int i = 0; i < vector.size(); i++) {
  
  	    if (first) {
  		first = false;
  	    } else {
  		result.append(comma);
  	    }
  
  	    result.append(vector.elementAt(i).toString());
  
  	}
  	return result.toString();
      }
docs: convert this object to a String, in the format
  of argument of REST GridFTP command, for instance:
  "0-29,32-89"
  The resulting String will preserve the features
  of ByteRangeList: (1) order and (2) separation