ListGrid filtering without DataSource

[kester]

Hi all!
I'm using smartGwt [3.0].

In my application i use only one ListGrid to display statistics data.
It's stored in mongoDb, so i just forward JSON data to client side.
As you understand, statistics data may has different structure by types - so i do recursively parse recieved data, get the set of keys and build necessary ListGridFields for ListGrid:

final ListGridField[] fields = new ListGridField[ fieldKeys.size() ];
for ( String key : fieldKeys ) {
    final ListGridField gridField = new ListGridField( key );
    gridField.setCanFilter( true );
    fields[ i ] = gridField;
    i++;
}
setFields( fields );

It works perfectly, but now i'd like to perform filtering for records, but i cant dynamically change DataSource fields, right?
DataSource.setFields(...) JavaDoc:

@throws IllegalStateException this property cannot be changed after the underlying component has been created

Is It possible to perform filtering in ListGrid without attached DataSource?

[Isomorphic]

Simple create a DataSource on the fly from the generated fields.