Setting nested object to null when selected option has empty value

Question

Hello,

I have a Class which models a User and another which models his country. Something like this:

public class User{
    private Country country;
    //other attributes and getter/setters
}

public class Country{
    private Integer id;
    private String name;
    //other attributes and getter/setters
}

I have a Spring form where I have a combobox so the user can select his country or can select the undefined option to indicate he doen't want to provide this information. So I have something like this:

<form:select path="country">
    <form:option value="">-Select one-</form:option>
    <form:options items="${countries}" itemLabel="name" itemValue="id"/>
</form:select>

In my controller I get the autopopulated object with the user information and I want to have country set to null when the "-Select one-" option has been selected. So I have set a initBinder with a custom editor like this:

@InitBinder
protected void initBinder(WebDataBinder binder) throws ServletException {
    binder.registerCustomEditor(Country.class, "country", new CustomCountryEditor());
}

and my editor do something like this:

public class CustomCountryEditor(){
    @Override
    public String getAsText() {
        //I return the Id of the country 
    }

    @Override
    public void setAsText(String str) {
        //I search in the database for a country with id = new Integer(str)
        //and set country to that value
        //or I set country to null in case str == null
    }
}

When I submit the form it works because when I have country set to null when I have selected "-Select one-" option or the instance of the country selected. The problem is that when I load the form I have a method like the following one to load the user information.

@ModelAttribute("user")
public User getUser(){
   //loads user from database
}

The object I get from getUser() has country set to a specific country (not a null value), but in the combobox is not selected any option. I've debugged the application and the CustomCountryEditor works good when setting and getting the text, thoughgetAsText method is called for every item in the list "countries" not only for the "country" field.

Any idea? Is there a better way to set null the country object when I select no country option in the combobox?

Thanks

Answer 1

Did you check the database table for User what value for country is being set when you save the user ... is it null of is there some value?

Answer 2

The problem was that I was retrieving the object User from Spring Security principal object. I've changed my getUser method so I get Id from Spring Security and the I search in database and now everything works, though I don't understand why this happend cause I can see in debug that the country was loaded in the user by Spring Security.