Use of ZF framework validator [custom validator and validator chain]

homework exercises

require_once("Zend/Loader.php");
//Introduce the validator class and the functional class of the validator (Int), and the custom interface class;
Zend_Loader::loadClass( 'Zend_Validate');
Zend_Loader::loadClass('Zend_Validate_Int');
Zend_Loader::loadClass('Zend_Validate_Interface');
//Add custom validator function class (GongBeiNum) [common multiple]
Class GongBeiNum implements Zend_Validate_Interface
 {
 //Declare the error message reporting attribute in the interface
 protected $_messages = array();
 //Declare the verification method in the interface
 public function isValid($num)
 {
 if (!($num%3 ==0) && !($num%5==0))
 {
 //If the verification fails, the error message return value is given to the error message report attribute
 $this -> _messages[] = "Your message The entered value is not a common multiple of 3 and 5! ";
 // Terminate the program
 return false;
 }
 // Return true
 return true;
 }
 // Define the error reporting method of the interface
 public function getMessages()
 {
 return $this -> _messages;
 }
 //Define extraction error messages (optional)
 public function getErrors()
 {

 }
}
//Out-of-class definition of common multiple detection method
function check_num($num )
{
 //Instantiate the validator class
 $Validate = new Zend_Validate();
 //Add a validator function class, add a custom validator function class, and form a validator chain
 $Validate - > addValidator(new Zend_Validate_Int())
 -> addValidator(new GongBeiNum());
 //Validate parameters
 if (!$Validate -> isValid($num))
 {
 //Loop if error Error message and output
 foreach ($Validate -> getMessages() as $value)
 {
 echo $value . "";
 return false;
 }
 }
}

//Specify the judgment Value
$num1 = '15';
//Run the check method
check_num($num1);
?>