plementation to be run on a background thread
 If your class doesn't need to refresh then override the filter
 method above to avoid unnecessary threading</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../../com/atakmap/android/hierarchy/items/AbstractHierarchyListItem2.html#refreshImpl--">refreshImpl</a></code>&nbsp;in class&nbsp;<code><a href="../../../../com/atakmap/android/hierarchy/items/AbstractHierarchyListItem2.html" title="class in com.atakmap.a