Section 11 - Overloading - Classes and Objects in PHP5[11]_PHP Tutorial

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Section 11--Overloading
PHP4 already has overloading syntax to establish mapping to external object models, like Like Java and COM. PHP5 brings powerful object-oriented overloading, allowing programmers to create custom behaviors to access properties and call methods.
Overloading can be accomplished through several special methods __get, __set, and __call Proceed. PHP will call these methods when the Zend engine tries to access a member and cannot find it.
In Example 6.14, __get and __set replace all accesses to the attribute variable array. You can implement any type if necessary Filter the way you want. For example, a script can disable setting property values, starting with a certain prefix or containing a certain type of value. The
__call method illustrates how you call an undefined method. You call an undefined method When, the method name and parameters received by the method will be passed to the __call method, and PHP returns the value of __call to the undefined method.
Listing 6.14 User-level overloading
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 $function_name()
n");
print("Arguments: ");
print_r($args);
return(TRUE);
}
}
$o = new Overloader();
//invoke __set() Assign a value to a non-existent attribute variable and activate __set()
$o->dynaProp = "Dynamic Content";
//invoke __get() activates __get()
print($o->dynaProp . "
n");
//invoke __call() activates __call ()
$o->dynaMethod("Leon", "Zeev");
?>

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