/**
  * Parses the parameters to add user-defined contains strings.
  */
 private function _initialize()
 {
     $params = $this->getParameters();
     if ($params !== null) {
         foreach ($params as $param) {
             if (self::CONTAINS_KEY == $param->getType()) {
                 $cont = new Contains();
                 $cont->setValue($param->getValue());
                 array_push($this->_contains, $cont);
                 break;
                 // because we only support a single contains
             }
         }
     }
 }