cakephp中扩张自定义验证规则

function validateDependentFields($field){  
   $passed=true; 
    switch(true){     
    case array_key_exists('username',$field):    
         if(  $this->data['User']['user_type_id']==1 and (!isset($this->data['User']['username']) or empty($this->data['User']['username'])) )
{               
  $passed=false;      
       }
else{      
           $passed=true;           
  }      
   break;      
   case array_key_exists('class_of',$field):       
      if(  $this->data['User']['user_type_id']==1 and (!isset($this->data['User']['class_of']) or empty($this->data['User']['class_of'])) )
{   
              $passed=false;    
        
 }else
{           
      $passed=true; 
            }      
   break;  
   }     
return $passed; 
}