prevent php classes from being extends

Question

some time i trying to decode my own general file that contain the all important functions in a class but i think when i have class like

class A {
  public function test($value){

and the file encoded

may be some one do that

class B extends A {
  public function test($value){

and change the whole function that contain my code that i can expose my control

http://www.php.net/manual/en/language.oop5.php

Answer 1

Use the final keyword.

Answer 2

final class A {
  public function test($value){

or

class A {
  final public function test($value){