Question

I have a list which has a another list defined in it.So,assume them as a reflection objects.(List inside a list inside a list …so on). In my view I start with one YES/NO question and based on YES, I have to display a collection of data. Again when a user checks YES display the set.

I can achieve this by constructing the question and hiding them before presenting to the client and when user checks YES,I enable that set.But the collection which I am working is huge,so I don’t want to render the collection and hide if that is of no use. I would like to know if there is a better way to achieve this.(Spring MVC 3, Java 6)

Thanks

Answer 1

To load “nested” questions just when you actually need it you could use ajax.
For example, in your Spring MVC controller you could implement a method like this:

@RequestMapping("/nestedQuestions")
public @ResponseBody List<Question> getNestedQuestions(@RequestParam("parentQuestion") int id){
    return yourService.getChildrenQuestionsFor(id);
}

Question could be a simple object:

public class Question {

    private int id;
    private String text;

    // ...

}

Then in your page, if you are using jQuery:

function getNestedQuestions(parentQuestionId) {
    $.ajax({
        type : "GET",
        url : '/nestedQuestions',
        data : {
            parentQuestion : parentQuestionId
        },
        success : function(data) {
            // for each question in data, show it...
        },
        error : function(jqXHR, textStatus, errorThrown) {
            alert(jqXHR.responseText);
        }
    });
}

The getNestedQuestions function can be called from your radiobutton onChange event handler, passing the parent question id.