public function shouldGenerateOldValue()
 {
     switch ($this->getTransactionType()) {
         case self::TYPE_INTERFACE:
             return false;
     }
     return parent::shouldGenerateOldValue();
 }
 public function getTitle()
 {
     $author_phid = $this->getAuthorPHID();
     $old = $this->getOldValue();
     $new = $this->getNewValue();
     switch ($this->getTransactionType()) {
         case self::TYPE_NAME:
             if ($old === null) {
                 return pht('%s created this service.', $this->renderHandleLink($author_phid));
             } else {
                 return pht('%s renamed this service from "%s" to "%s".', $this->renderHandleLink($author_phid), $old, $new);
             }
             break;
         case self::TYPE_LOCK:
             if ($new) {
                 return pht('%s locked this service.', $this->renderHandleLink($author_phid));
             } else {
                 return pht('%s unlocked this service.', $this->renderHandleLink($author_phid));
             }
             break;
     }
     return parent::getTitle();
 }