code: public static String formatParameterList(Collection<String> value) {
  		return value == null ? null : StringUtils.collectionToDelimitedString(value, " ");
  	}
docs: Formats a set of string values into a format appropriate for sending as a single-valued form value.
  
  @param value The value of the parameter.
  @return The value formatted for form submission etc, or null if the input is empty