Draft diskaro Request system

<?php

namespace Request;

require_once('Track.php');

abstract class Request {
    protected $class = null;
    protected $response = null;

    //
    protected function __construct($data) {
        $this->class = $data['class'];
    }

    public function getResponse() {
        if($this->response === null)
            $this->process();
        return $this->response;
    }

    protected abstract function process();

    //
    public function log($f = 'foo') {
        $s = print_r($this, true);
        //file_put_contents($f, $s);
        echo "<pre>$s</pre>";
    }

    //
    public static function parse($data) {
        switch($data['type']) {
            case 'get':
                return new Get($data);
            case 'update':
                return new Update($data);
            case 'add':
                return new Add($data);
            case 'delete':
                return new Delete($data);
            default:
                throw new Exception('Unknown/Unsupported request type: '.$data['type']);
        }
    }
}

//
class Get extends Request {
    protected $constraint = null;

    //
    public function __construct($data) {
        parent::__construct($data);
        $this->constraint = $data['constraint'];
    }

    //
    protected function process() {
        $this->response = \DataCore::jsonRequest($this->class, $this->constraint);
        return $this;
    }
}

//
class Update extends Request {
    protected $json = null;

    //
    public function __construct($data) {
        parent::__construct($data);
        $this->json = $data['data'];
    }

    protected function process() {
        $data = json_decode($this->json);
        $target = new $this->class($data->id);
        $target->update($data);
        $this->response = 'Update applied';
        return $this;
    }
}

//
class Add extends Request {
    protected $json = null;
    protected $obj  = null;

    //
    public function __construct($data) {
        parent::__construct($data);
        $this->json = $data['data'];
    }

    protected function process() {
        $class = $this->class;
        try {
            $this->obj = $class::addJSON($this->json);
            $this->response = json_encode($this->obj);
        }
        catch(\PDOException $e) {
            $this->response = json_encode([
                'success' => false,
                'error'   => [
                    'code'    => $e->errorInfo[0],
                    'message' => $e->errorInfo[2],
                ],
            ]);
        }
        return $this;
    }
}

//
class Delete extends Request {
    //
    protected $id = null;

    //
    public function __construct($data) {
        parent::__construct($data);
        $this->id = $data['id'];
    }

    //
    protected function process() {
        $class = $this->class;
        $class::remove($this->id);
        $this->response = 'Record removed from DB';
        return $this;
    }
}

?>