使用自定义对象创建界面功能

Question

Is there an oppotunity to create an interface function in PHP, where a parameter requires to be an object, but not specified, what object it has to be?

Now my code looks like this:

interface Container {
    public static function add(\Employee $element);
}

Right now I can just implement the function with a parameter, which requires an instance from "Employee". When I now implement it in a class it looks like this:

class EmployeeContainer implements Container {
    public static function add(\Employee $element) {
        $pnr = $element->getPNR();
    }
}

When I create another class, that implements Container and set the required Object for example to Trainee, the PHP compiler throws an error:

class TraineeContainer implements Container {
    public static function add(\Trainee $element) {
        $pnr = $element->getPNR();
    }
}

Fatal error: Declaration of TraineeContainer::add($element) must be compatible with Container::add(Employee $element)

Is there a way to set in the interface the required object to a custom object?

Why I want this?

Many IDE's supporting this form of instance description to suggest methods based on an object.

Answer 1

Custome object argument is not possible in interface but you can achieve it in other way.

create a common base class

class SomeBaseClass{

}

extend your classes

class Employee extends SomeBaseClass{

}

class Trainee extends SomeBaseClass{

}

then use SomeBaseClass as argument in your interface

interface Container {
    public static function add(SomeBaseClass $element);
}

class EmployeeContainer implements Container {
    public static function add(SomeBaseClass $element) {
        $pnr = $element->getPNR();
    }
}

class TraineeContainer implements Container {
    public static function add(SomeBaseClass $element) {
        $pnr = $element->getPNR();
    }
}

It seems you have getPNR common function so you can create an abstract class or interface and use that in your child classes.