wrap.php

<?php

abstract class DefaultController {
    public function read($id) {
        if( empty($id) ) {
            throw Exception("No ID specified!");
        }
        $this->_read($id);
    }
    public abstract function _read($id);
}

class PostsController extends DefaultController {
    public function _read($id) {
        print "You were trying to read post with id {$id}"
        die();
    }
}