PHP 5 will also support the idea of a "final" member variable or property which prevents any further extending of that class 

<?php
    
    final class final_example {

        function foobar() { /* ... */ }

    }

    /* You can't do this, final_example is declared final */
    class tester extends final_example {

        function foobar() { /* ... */ }

    }

?>
Member methods may also be declared final, preventing them specifically from being overloaded in a sub class 

<?php

    class finalfunc {

        final function dosomething() { /* ... */ }
        function foobar() { /* ... */ }
    }

    class anotherclass extends finalfunc {

        function foobar() { /* something more */ }

        /* This can't work, dosomething() is 'final' */

        function dosomething() { /* This breaks */ }

    }

?>