/**
  * Locate interface by a given name
  *
  * @param  lang.XPClass $class
  * @param  string $name
  * @return lang.XPClass
  * @throws lang.ElementNotFoundException
  */
 private function interfaceNamed($class, $name)
 {
     foreach ($class->getInterfaces() as $iface) {
         if (strstr($iface->getName(), $name)) {
             return $iface;
         }
     }
     throw new ElementNotFoundException('Class ' . $class->getName() . ' does not implement ' . $name);
 }