Yii Framework: get/set methods and others.

A.php

<?php
class A
{
    private $test;

    public function __get($name)
    {
        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            return $this->$getter();
        }
    }

    public function __set($name, $value)
    {
        $setter = 'set' . $name;
        if (method_exists($this, $setter)) {
            return $this->$setter($value);
        }
    }

    public function __isset($name)
    {
        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            return $this->$getter() !== null;
        }
    }

    public function __unset($name)
    {
        $setter = 'set' . $name;
        if (method_exists($this, $setter)) {
            return $this->$setter(null);
        }
    }

    public function getTest()
    {
        return $this->test;
    }

    public function setTest($value)
    {
        $this->test = $value;
    }
}

$a = new A();
var_dump(isset($a->test)); // false
var_dump($a->test); // null

$a->test = 'test';
var_dump(isset($a->test)); // true
var_dump($a->test); // test

unset($a->test);
var_dump(isset($a->test)); // false
var_dump($a->test); // null