private Field createField( final SelectionEvent<Integer> selectionEvent ) {
if ( selectionEvent.getSelectedItem() == FieldData.TYPE_FACT ) {
return new FactAssignmentField( field.getName(), helper.getFieldType() );
} else {
if ( selectionEvent.getSelectedItem() == FieldData.TYPE_COLLECTION ) {
CollectionFieldData collectionFieldData = new CollectionFieldData();
collectionFieldData.setName( field.getName() );
return collectionFieldData;
} else {
FieldData fieldData = new FieldData( field.getName(), "" );
fieldData.setNature( selectionEvent.getSelectedItem() );
return fieldData;