/**
  * Defined by Zend_Validate_Interface
  *
  * Returns true if and only if $value doesn't exist already as page name
  *
  * @param  string $value
  * @return boolean
  */
 public function isValid($value)
 {
     $value = (string) $value;
     $this->_setValue($value);
     $mdlPage = new Model_Page();
     if ($mdlPage->pagenameExists($value, $this->getExclude())) {
         $this->_error(self::EXISTS);
         return false;
     }
     if ('admin' == strtolower($value)) {
         $this->_error(self::ISADMIN);
         return false;
     }
     if ('public' == strtolower($value)) {
         $this->_error(self::ISPUBLIC);
         return false;
     }
     return true;
 }
 /**
  * Defined by Zend_Validate_Interface
  *
  * Returns true if and only if $value does exist already as page name
  *
  * @param  string $value
  * @return boolean
  */
 public function isValid($value)
 {
     $value = (string) $value;
     $this->_setValue($value);
     $mdlPage = new Model_Page();
     if ($mdlPage->pagenameExists($value, $this->getExclude())) {
         return true;
     }
     $this->_error(self::NOT_EXISTS);
     return false;
 }