/** * @param string $subject * @return null */ public function setSubject($subject) { if (!isset($this->loadedFields['subject'])) { $this->loadProperties(); } $oldValue = null; if (array_key_exists('subject', $this->loadedValues)) { $oldValue = $this->loadedValues['subject']; } if ($oldValue === $subject) { $this->subject = $subject; return; } return parent::setSubject($subject); }