Clear GUI forms when created through spring as a singleton bean

Question

In a desktop application created using java and spring, the GUI forms are created as singleton beans and therefore whenever a form is displayed, all the preveously entered values are there. Is there a better way to get a fresh form than clearing each form field through java code? Thanks in advance

is it common practice to use singleton beans in GUI apps? And, is it common to use springframework to create GUI apps? It seems sort of surprising to me, because GUI & spring doesn't seem like a good fit. But perhaps what you want is to use prototype scope beans rather than the default singleton scope. — Kevin, Mar 22 '12 at 15:25
Is there a reason you chose singleton scope for this form object? — Roy Truelove, Mar 22 '12 at 15:29
This is an half way developed application that I have to work with. Is there any better way to implement the same? — Dilini Rajapaksha, Mar 26 '12 at 13:44

Joost · Answer 1 · 2012-04-03T13:35:37.317

2

You could force a new singleton to be instantiated like this

public class MyForm {
    // The instance
    private static MyForm instance = new MyForm();
    // Private constructor prevents instantiation from other classes
    private MyForm() { }
    // Get the singleton
    public static MyForm getInstance() { return instance; }

    // Force a new instance to be created         
    public static void resetInstance() {
           instance = new MyForm();
    }
}

But this is not really singleton behaviour anymore and maybe you should just use a new instantiated class. Something like:

myPanel.removeAll();
myPanel.add(new MyForm());

(the constructor should become public of course)

edited Apr 03 '12 at 13:35

answered Mar 28 '12 at 11:45

Joost

3,169
2
22
40

Thanks, I'll try your second sugession. – Dilini Rajapaksha Mar 29 '12 at 03:06
I think I found a better solution, but not sure whether it is the correct way. I override the `dispose` method and called `init` method after `super.dispose()`, in the `init` method, added the following line at the begining: `getContentPane().removeAll();`. It works well for my requirement, when I want the data to remain in the form, I simply hide the form and when I want a fresh form, I dispose the form and show the form again. If you find any faults in this method, please comment. – Dilini Rajapaksha Apr 04 '12 at 05:32

score 1 · Answer 2 · answered Mar 28 '12 at 12:52

1

I would suggest a simpler alternative, please use singleton=false. If you want to retain some of the initialization snippets, then use init method or bean post processors.

answered Mar 28 '12 at 12:52

questzen

3,260
18
21

Could you please explain the usage of init method and bean post processors? – Dilini Rajapaksha Mar 29 '12 at 03:28
This is answered here: http://stackoverflow.com/questions/1088550/spring-how-to-call-a-method-after-bean-initialization-is-complete – questzen Mar 29 '12 at 11:54

score 0 · Accepted Answer · answered Apr 05 '12 at 08:24

I override the dispose method and called init method after super.dispose(), in the init method, added the following line at the begining: getContentPane().removeAll();. It works well for my requirement, when I want the data to remain in the form, I simply hide the form and when I want a fresh form, I dispose the form and show the form again.

Clear GUI forms when created through spring as a singleton bean

3 Answers3