addGeneratedColumn / generateCell explanation

Hi,

Can someone explain when generateCell is called?

From my experientation, it seems to be that it is called for each row and each cell in a table.

For example if the table has 5 columns, three regular and two genrated it seems to be called 5 times, one time for each cell for any given row.   It also seems to be called for each row in the table.  So 5 columns x 3 rows = 15 times.   

If another row is added to the table it seems like it is called 20 times again.   

If I had a table with 100 rows it would be called 500 times?

Is there a way to blow out of a call for a column of no interest?  
If processing "Middle Name" return null;

I'm looking to save some calls / time.

I'm using vaadin 7.7.6

Thank you for your help!
Berk

I am not sure if it won't actually save the additional calls, but you can set the visible columns after you set the datasource.

table.setVisibleColumns(prpoertyIds)

If it has to evaluate each record value and if all records have null, then you want to hide, you can't avoid it.