public void setRoots(final List<ExplorerNode> roots) {
        parents.clear();

        // Once the tree structure changes ensure we auto select descendants of selected ancestors.
        final Set<ExplorerNode> selectedSet = getSelectedSet();
        stateMap.clear();

        if (roots != null) {
            addChildren(null, roots);
            selectChildren(null, roots, false, selectedSet);
        }
    }
Get the set of selected items.

@return the set of selected items
stroom-core-client/src/main/java/stroom/explorer/client/presenter/TickBoxSelectionModel.java