PHP的对象和类

<?php 
class Overloader 
{ 
private $properties = array(); 

function __get($property_name) 
{ 
if(isset($this->properties[$property_name])) 
{ 
return($this->properties[$property_name]); 
} 
else 
{ 
return(NULL); 
} 
} 

function __set($property_name, $value) 
{ 
$this->properties[$property_name] = $value; 
} 

function __call($function_name, $args) 
{ 
print("Invoking $function_name()<br>n"); 
print("Arguments: "); 
print_r($args); 

return(TRUE); 
} 
} 
$o = new Overloader(); 

//invoke __set() 给一个不存在的属性变量赋值,激活__set() 
$o->dynaProp = "Dynamic Content"; 

//invoke __get() 激活__get() 
print($o->dynaProp . "<br>n"); 

//invoke __call() 激活__call() 
$o->dynaMethod("Leon", "Zeev"); 
?>