Spring Roo add an empty option to a combo

Spring roo by default creates a combo box with widgetType "dijit.form.FilteringSelect" applied on it , this combo box doesn't contain an empty option.

To add an empty option to it please follow the below steps

In your java code when you are preparing a List for that combo box try to add first option with

code =0 and value = -- Not Selected

and then add all the other options in that list.

A simple java code snipet I am using is

ComboDTO comboDTO=new ComboDTO();
comboDTO.setCode("0");
comboDTO.setDescription("--Not Selected--");
list.add(comboDTO); //This is the list which will be used to populate values in combo box

The option having the code = 0 will be shown as the first element in your combo box. Now if you want it to be mendatory field implement your Validator in and check if the option slected in combo has code=0 send an error back

Sample code for checking the value and sending error back from validator is like below

 if(myObject.getFieldCode().equals("0")){
  errors.rejectValue("fieldCode", "required.fieldCode");
 }
 

 This way you can have a combo box with an empty option and can check the validity at server side.

Unfortunatly I couldn't find a way to show dojo type notification at client end if the user has not selected a valid option in the combo box. But this is working for me now.