* @since 3.8 beta6
*/
public static Collection<String> getNotSupportedFunctionNames() {
Collection<String> lst = new TreeSet<String>();
for (int i = 0; i < functions.length; i++) {
Function func = functions[i];
if (func != null && (func instanceof NotImplementedFunction)) {
FunctionMetadata metaData = FunctionMetadataRegistry.getFunctionByIndex(i);
lst.add(metaData.getName());
}
}