Is it possible to have an empty integer?

[dlite922]

Sorry for the lolcat title, but seriously I don't know what the best approach would be.

I'm working with a table model. In the data I have a String, 2 Integers, and 1 Boolean column.

The Boolean and one of Integer columns CAN have empty values.

When I'm populating the data I'm setting the default values of the Boolean to false and the integer to null like so:

 
result[ri][0] = sdtSrvc.getServiceId();
result[ri][1] = "   "+sdtSrvc.getCallTag();
result[ri][2] = (mapSrvc != null) ? mapSrvc.getCableID() : null; //<--------- Empty Integer Needed Here instead of null
result[ri][3] = (mapSrvc != null) ? mapSrvc.getEnabledFlag() : false;
result[ri][4] = sdtSrvc.getTransportStreamId();
 
 

Symptom of problem:
The records that DO have a value, JTable treats them like a string and aligns them to the left. Yuck!

I should mention I have overridden the AbstracTableModel's getColumnClass() like this:

 
    @Override
    public Class getColumnClass(int c)
    {
        Object val = getValueAt(0, c);
 
        if(val == null) {
            Integer scrap = 0;
            return scrap.getClass();
        } else
        {
            return getValueAt(0, c).getClass();
        }
    }
 

This method is called by JTable's Cell Render..er. As you can see I'm creating an int and returning it.

it works, but again Yuck! and what if there's an empty record in the String column. The cell render will treat it as an int.

If I could somehow declare my default value as an empty int that would be great and I can change the above method to just the return line:

return getValueAt(0, c).getClass();

and be done with it!

My other option is to evaluate c (the column index) and find which column it is and hard code the default type of that column, but again what if I reorder my columns or drop columns in the future? I'd rather not have this mess to maintain.

In short, can I have my cake and 'not' eat it too?

: )

Thanks for any feedback guys!


Dan

[Dheeraj Joshi]

Integer can not be empty Dan. But you can display them as Strings. So if null is the value of in just display "". That is nothing to display.

Probably i am confused about your question :(

Regards
Dheeraj Joshi

[dlite922]

Thanks Dheeraj, That doesn't get the rid of the symptom. Which is: It makes the table think that column is a string instead of an integer, hence rending the numbers further down the list as a string!

If I hard code logic in the getColumnClass() method, then I'd hard code the column index. Something I don't want to do because it requires maintenance.

How would you go about handling this situation? At the moment I'm defaulting every empty column to an integer.

Thanks again,

Dan

[Dheeraj Joshi]

Why can't you render all the integers as String and display it in the table?

Yes, Overriding may not be a good option.

I would default all empty columns as a String.

Regards
Dheeraj Joshi

[Dheeraj Joshi]

What i am saying even if the values is int or null render it as String. (Unless your app is not very bulky).

It solves the rendering problems.

Regards
Dheeraj Joshi

[dlite922]

So I can do that, but it's not just the empty values that are rendered as string, but the integers in that row will now be displayed as integer (i.e. they are left aligned instead of right aligned, you can enter non-number characters instead of just digits, etc)

Thanks,

[Dheeraj Joshi]

I thought it is just displaying(read-only). But anyway if user can enter the values for the table then displaying them as String is not a good idea, since it involves a lot of validations when user enters some characters or symbols.

Regards
Dheeraj Joshi