public function validate($value) { $is_valid = true; if ($value) { $rule = new Rule_Date(); $is_valid = $rule->isValid($value); if (!$is_valid) { $GLOBALS['Response']->addFeedback('error', $GLOBALS['Language']->getText('plugin_tracker_common_artifact', 'error_date_value', array($this->field->getLabel()))); } } return $is_valid; }