Last Updated: May 25, 2016

check if a class exists within the extending hirachy

PHP middle class instance of checking

My Problem was that i extended a lot of classes from the BaseClass.
But i needed only those classes wich are extending from a certain class (MiddleClass) within the chain
eg:

SecondClass extends ->
 FirstClass extends ->
 BaseClass

ThirdClass extends ->
 SecondClass extends ->
 MiddleClass extends ->
 FirstClass extends ->
 BaseClass

FourthClass extends ->
 SecondClass extends -> 
 MiddleClass extends ->
 FirstClass extends ->
 BaseClass

Since im in a loop, it would not be recommended to do this:

if ($myclass instanceoff ThirdClass || $myclass instanceoff FourthClass) then do;

instead i implemented a method to do this

if ($myclass->isInstanceof(MiddleClass)) then do;

here is how to do it

class BaseClass
{


 public function getInstances($instance = null, $list = array())
 {

 if (is_null($instance)) {
 $instance = $this;
 }

 $parent = get_parent_class($instance);

 if ($parent) {
 $list[] = $parent;
 $list = self::getInstances($parent, $list);
 }

 return $list;
 }

 public function isInstanceOf($class)
 {
 foreach ($this->getInstances() as $instance) {
 if (strpos($instance, $class) !== false) {
 return true;
 }
 }
 return false;
 }

}

class FirstClass extends BaseClass
{

}

class SecondClass extends FirstClass
{

}

$SecondClass = new SecondClass();

$result = $SecondClass->isInstanceOf("FirstClass");

var_dump($result);