code: void addPasswordField(final String name, final String value)
              throws IllegalStateException {
  
          addField(name, (value == null) ? null : "*****");
  
      }
docs: Adds a string representation of the given password field.
  
  @param name
  the name of the field
  @param value
  the value of the field
  @throws IllegalStateException
  if the string representation has already been completed