Final Keyword

PHP 5 introduces the final keyword, which prevents child classes from overriding a method or variable by prefixing the definition with final.

Example 18-21. Final methods example

<?php
class BaseClass {
   
public function test() {
       echo
"BaseClass::test() called\n";
   }
   
   
final public function moreTesting() {
       echo
"BaseClass::moreTesting() called\n";
   }
}

class
ChildClass extends BaseClass {
   
public function moreTesting() {
       echo
"ChildClass::moreTesting() called\n";
   }
}
// Results in Fatal error: Cannot override final method BaseClass::moreTesting()
?>