Php/docs/language.oop5.final

• PHP Manual
• Classes and Objects
• Final Keyword

Final Keyword

PHP 5 introduces the final keyword, which prevents child classes from overriding a method by prefixing the definition with final. If the class itself is being defined final then it cannot be extended.

Example #1 Final methods example

<?phpclass 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()?>

Example #2 Final class example

<?phpfinal class BaseClass {   public function test() {       echo "BaseClass::test() called\n";   }   // Here it doesn't matter if you specify the function as final or not   final public function moreTesting() {       echo "BaseClass::moreTesting() called\n";   }}class ChildClass extends BaseClass {}// Results in Fatal error: Class ChildClass may not inherit from final class (BaseClass)?>

Note:

Properties and constants cannot be declared final, only classes and methods may be declared as final.