private TreePathValueProvider createValueProvider() {
Map<Predicate<Object>, Category> categories = ImmutableMap.of(
instanceOf(LocalDate.class), DATE,
instanceOf(WorkspaceStorage.class), WORKSPACE);
ICategorizer categorizer = new Categorizer(categories);
IConverter<TreePath> converter = new TreePathDurationConverter();
return new TreePathValueProvider(categorizer, contentProvider, converter, DATE);
}