How to prevent a particular method from overriding?

Question

I have a parent class:

class parent{
   var $a = 'param1';
   var $b = 'param2';
   public summary(){
      if($this->a<0 || $this->b<0)
         return FALSE;
      return $this->a+$this->b;
   }
   public set_null(){
      $this->a = null;
      $this->a = null;
   }
}

I need to prevent the summary method from overriding in child class, maybe my team doesn't know if summary method exists before.

class child extends parent{
   public summary(){
      return $this->a+$this->b;
   }
   public set_null(){
      $this->a = 0;
      $this->b = 0;
   }
}

Can anyone help me with this problem?

Answer 1

You can do it using final modifier before summary() method definition in your parent class.