PHP以静态方式检查继承

Question

I wonder if it is possible to check the inheritance of a class in a static way.

In cases I get just a class name with its namespace I can do:

    $oObject = new $sClassName();
    if(is_a($oObject, $sParentClassName)) { return true; }

But here it is mandatory to have an instance of that class.

The only static check I have found so far is the following:

    if(method_exists($sClassName, $sMethodNameFromParent)) { return true; }

But checking just for a method is no good, because I can't be sure whether the class in question inherited it from that specific parent, some other parent or implemented it all by itself.

Is there any way to check the inheritance in a static manner? Thanks in advance!

Answer 1

You can use Reflection::isSubclassOf for this.

class A {}
class D {}
class B extends D {}
class C extends B {}

$reflected = new ReflectionClass('C');

echo $reflected->isSubclassOf('B'); // true
echo $reflected->isSubclassOf('D'); // true
echo $reflected->isSubclassOf('A'); // false

No instance of C will be created, and will work even if the class has __construct arguments