If you use ExtendedDataModel which implements Modifiable as value of DataTable you should manage filtering and sorting yourself.
you are right. when I remove the method modify and when my column is not implemented the interface Modifiable then the framework sort the datavalues by itself.
it is ok.
The Component ExtendedDataTable has a very usefull feature: "groupBy". The disadvantage of ExtendedDataTable is that it is very very slow.
So I try to implement simple DataTable and if I know which column should be sorted, then I can go throw the sorted column and when the value is changed then I add new empty row .
On the page the user can see goups of dataValue.
do you know what I mean??
For this purpose I tried to implement the method modify.
The first problem I still dont know which column should be sorted.
The second the framework dont want to sort the data. I thought that I can call some method from framework and provide my Data to sort. But which Method??