(PHP 4, PHP 5)
is_subclass_of — Checks if the object has this class as one of its parents
Checks if the given object has the class
class_name as one of its parents.
objectA class name or an object instance
class_nameThe class name
allow_string
If this parameter set to false, string class name as object
is not allowed. This also prevents from calling autoloader if the class doesn't exist.
This function returns TRUE if the object object,
belongs to a class which is a subclass of
class_name, FALSE otherwise.
| Versiunea | Descriere |
|---|---|
| 5.3.9 |
Added allow_string parameter
|
| 5.3.7 |
Added support for class_name to work with
interfaces
|
| 5.0.3 |
You may also specify the object parameter as a
string (the name of the class)
|
Example #1 is_subclass_of() example
<?php
// define a class
class WidgetFactory
{
var $oink = 'moo';
}
// define a child class
class WidgetFactory_Child extends WidgetFactory
{
var $oink = 'oink';
}
// create a new object
$WF = new WidgetFactory();
$WFC = new WidgetFactory_Child();
if (is_subclass_of($WFC, 'WidgetFactory')) {
echo "yes, \$WFC is a subclass of WidgetFactory\n";
} else {
echo "no, \$WFC is not a subclass of WidgetFactory\n";
}
if (is_subclass_of($WF, 'WidgetFactory')) {
echo "yes, \$WF is a subclass of WidgetFactory\n";
} else {
echo "no, \$WF is not a subclass of WidgetFactory\n";
}
// usable only since PHP 5.0.3
if (is_subclass_of('WidgetFactory_Child', 'WidgetFactory')) {
echo "yes, WidgetFactory_Child is a subclass of WidgetFactory\n";
} else {
echo "no, WidgetFactory_Child is not a subclass of WidgetFactory\n";
}
?>
Exemplul de mai sus va afișa:
yes, $WFC is a subclass of WidgetFactory no, $WF is not a subclass of WidgetFactory yes, WidgetFactory_Child is a subclass of WidgetFactory
Example #2 is_subclass_of() using interface example
<?php
// Define the Interface
interface MyInterface
{
public function MyFunction();
}
// Define the class implementation of the interface
class MyClass implements MyInterface
{
public function MyFunction()
{
return "MyClass Implements MyInterface!";
}
}
// Instantiate the object
$my_object = new MyClass;
// Works since 5.3.7
// Test using the object instance of the class
if (is_subclass_of($my_object, 'MyInterface')) {
echo "Yes, \$my_object is a subclass of MyInterface\n";
} else {
echo "No, \$my_object is not a subclass of MyInterface\n";
}
// Test using a string of the class name
if (is_subclass_of('MyClass', 'MyInterface')) {
echo "Yes, MyClass is a subclass of MyInterface\n";
} else {
echo "No, MyClass is not a subclass of MyInterface\n";
}
?>
Exemplul de mai sus va afișa:
Yes, $my_object is a subclass of MyInterface Yes, MyClass is a subclass of MyInterface
Notă:
Utilizarea acestei funcții va duce la utilizarea oricărui autoîncărcător înregistrat dacă clasa nu este cunoscută deja.