Pass a parent class as a parameter to a function - php

Question

This is a basic PHP question, and somehow I couldn't find any information about it.
So what I'm trying to do is to pass a parent class to a function so all of its children class can be passed too.
Is there anyway to do it?
function transform(Fruit $fruit){}
transform($orange)
transform($apple)
Update :
Looks like I need to show the situation more.
So what I have is a transformer parent
class ResourceTransformer{
public function transform(ResourceModel $model){}
}
And its child
class ColorTransformer extends ResourceTransformer{}
Now what I want to do is passing ColorModel, a child of ResourceModel to ColorTransformer.
class ColorModel extends ResourceModel{}
when I'm doing that it throws an error like this:
Type error: Argument 1 passed to App\\Modules\\Product\\Transformer\\ResourcesTransformer::transform() must be an instance of App\\Modules\\Product\\Models\\ResourceModel, instance of App\\Modules\\Product\\Models\\ColorModel given.
So basically, ColorTransformer can't accept ColorModel and only accept ResourceModel, yet ColorModel is a child of ResourceModel. Might be some of you can give me more enlightement.

Answer 1

I have tried this code to check your problem
class ResourceModel { }
class ResourceTransformer
{
public function transform(ResourceModel $model)
{
var_dump($model);
}
}
class ColorTransformer extends ResourceTransformer { }
class ColorModel extends ResourceModel { }
$transformer = new ColorTransformer();
$model = new ColorModel();
$transformer->transform($model);
and i've got correct result
object(ColorModel)#2 (0) { }
If this is not working in your case then it's look like the class ResourceModel form this part of your code
class ResourceTransformer{
public function transform(ResourceModel $model){}
}
is not the same that in this part
class ColorModel extends ResourceModel{}
You told in comment that the problem is only with the ColorModel but your information about error tell us that namespaces for ResourceModel and ColorModel are the same so I think the problem is with your ResourceTransformer class definition - do you have this code somewhere in top of your file with this definition?
use App\Modules\Product\Models\ResourceModel;
If you don't then do you have an another declaration of the ResourceModel class somewhere in your file with ResourceTransformer class definition?
The other thing I see in your question is the difference between this part of your code
class ResourceTransformer{
public function transform(ResourceModel $model){}
}
and class name in your error
Type error: Argument 1 passed to App\Modules\Product\Transformer\ResourcesTransformer::transform() must be an instance of App\Modules\Product\Models\ResourceModel, instance of App\Modules\Product\Models\ColorModel given.
Look that in error you have a class ResourcesTransformer and you tell us that this class is named ResourceTransformer. If this difference is ok then your problem should be placed in file with declaration of the ResourcesTransformer class.

Answer 2

You can simply pass name of class as a string and dinamically instantiate it:
function transform($name_of_class){
...
new $name_of_class;
}

Answer 3

Check the example please;
<?php
// function transform(Fruit $fruit){ //or
function transform($fruit){
print_r($fruit);
}
class Fruit{
public $name = null;
function __construct($name){
$this->name = $name;
}
}
transform(new Fruit('Apple')); // result: Fruit Object ( [name] => Apple )
echo '<br />';
$orange = new Fruit('Orange');
transform($orange); // result: Fruit Object ( [name] => Orange )