code: public static StringBinding transforming(ObservableValue<String> text, Function<String, String> transformer) {
  		return Bindings.createStringBinding(()
  			-> {
  			Function<String, String> func = transformer == null ? Function.identity() : transformer;
  			return text.getValue() == null ? "" : func.apply(text.getValue());
  		}, text);
  	}
docs: Creates a string binding that contains the value of the given observable string transformed using the supplied
  function.
  
  If the given observable string has a value of `null` the created binding will contain an empty string.
  
  If the given function has a value of `null` {@link Function#identity()} will be used instead.
  
  @param text
  the source string that will used for the conversion.
  @param transformer
  a non-interfering, stateless function to apply to the source string.
  @return a binding containing the transformed string.