Niekto objektovo zdatný mi vie vysvetliť pár riadkov kódu?

<?php
require_once('interface/interface.Validator.php');

abstract class PropertyObject implements Validator {
    protected $propertyTable = array();  //sluzi na ulozenie paru nazov/hodnota
                                         //umoznujucich prevod nazvu a atributu na 
                                                     //nazvy stlpcov v databaze
    protected $changeProperties = array(); //zoznam atributov ktorych hodnoty boli nazvy zmenane
    protected $data;   //vlastne data z databaze 
    protected $errors = array();
    
    public function __construct($arData) {
        $this->data = $arData;
    }
    
    public function __get($propertyName) {
        if(!array_key_exists($propertyName, $this->propertyTable)) {
            throw new Exception("Neplatný atribút \"$propertyName\"! ");
        }
        if(method_exists($this, 'get'. $propertyName)) {
            return call_user_func(array($this, 'get' .$propertyName));
        } else {
            return $this->data[$this->propertyTable[$propertyName]];
        }
    }
    
    public function __set($propertyName, $value) {
        if(!array_key_exists($propertyName, $this->propertyTable)) {
            throw new Exception("Neplatný atribút \"$propertyName\"! ");
        }
        if(method_exists($this, 'set'. $propertyName)) {
        return call_user_func(array($this, 'set' .$propertyName), $value);
        } else {
            
            //Pokial doslo k zemene hodnoty atributu a tato zmena niie je doposial 
            //zaznamenana v poli changedProperties array, prida sa.

            if($this->propertyTable[$propertyName] != $value && !in_array($properyName, $this->changedProperties)) {
                $this->changedProperties[] = $propertyName;
            }
            //nastavenie novej hodnoty
            $this->data[$this->propertyTable[$propertyName]] = $value;
        }
    }
    
    public function validate();
}
        





?>

if(method_exists($this, 'get'. $propertyName)) {
            return call_user_func(array($this, 'get' .$propertyName));
        } else {
            return $this->data[$this->propertyTable[$propertyName]];
        }

public function __get($propertyName) {
                               if(!array_key_exists($propertyName, $this->propertyTable)) {
                                               throw new Exception("Neplatný atribút \"$propertyName\"! ");
                               }
                               if(method_exists($this, 'get'. $propertyName)) {
                                               return call_user_func(array($this, 'get' .$propertyName));
                               } else {
                                               return $this->data[$this->propertyTable[$propertyName]];
                               }

$objPropertyObject = new PropertyObject;

$objPropertyObject->get(“Janko”);