_displayGroups = new ArrayList<DisplayGroup>();
Map<?, ?> variables = _modelMap.getMap("variables");
if (variables != null) {
EOModelMap variableMap = new EOModelMap(variables);
Set<Map.Entry<String, Object>> variableEntries = variableMap.entrySet();
for (Map.Entry<String, Object> entry : variableEntries) {
if (entry.getValue() instanceof Map) {
EOModelMap entryMap = new EOModelMap((Map<?, ?>) entry.getValue());
String className = entryMap.getString("class", true);
//XXX This should support subclasses of WODisplayGroup