is_subclass_of(3) [php man page]

IS_SUBCLASS_OF(3)							 1							 IS_SUBCLASS_OF(3)

is_subclass_of - Checks if the object has this class as one of its parents

SYNOPSIS

       bool is_subclass_of TRUE (mixed	$object, string  $class_name, [bool  $allow_string])

DESCRIPTION

	Checks if the given $object has the class $class_name as one of its parents.

PARAMETERS

	      o $object
		- A class name or an object instance. No error is generated if the class does not exist.

	      o $class_name
		- The class name

	      o $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.

RETURN VALUES

	This function returns TRUE if the object $object, belongs to a class which is a subclass of $class_name, FALSE otherwise.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 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)		    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES

       Example #1

	      is_subclass_of(3) 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
";
	      } else {
		echo "no, $WFC is not a subclass of WidgetFactory
";
	      }

	      if (is_subclass_of($WF, 'WidgetFactory')) {
		echo "yes, $WF is a subclass of WidgetFactory
";
	      } else {
		echo "no, $WF is not a subclass of WidgetFactory
";
	      }

	      // usable only since PHP 5.0.3
	      if (is_subclass_of('WidgetFactory_Child', 'WidgetFactory')) {
		echo "yes, WidgetFactory_Child is a subclass of WidgetFactory
";
	      } else {
		echo "no, WidgetFactory_Child is not a subclass of WidgetFactory
";
	      }
	      ?>

	      The above example will output:

	      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(3) 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
";
	      } else {
		echo "No, $my_object is not a subclass of MyInterface
";
	      }

	      // Test using a string of the class name
	      if (is_subclass_of('MyClass', 'MyInterface')) {
		echo "Yes, MyClass is a subclass of MyInterface
";
	      } else {
		echo "No, MyClass is not a subclass of MyInterface
";
	      }
	      ?>

	      The above example will output:

	      Yes, $my_object is a subclass of MyInterface
	      Yes, MyClass is a subclass of MyInterface

NOTES

       Note

	      Using this function will use any registered autoloaders if the class is not already known.

SEE ALSO

       get_class(3), get_parent_class(3), is_a(3), class_parents(3).

PHP Documentation Group 													 IS_SUBCLASS_OF(3)