Class not found, when trying to pass class name as string, namespace issue

Question

Here is a method, in which a string is passed, using that string an instance is created. Example method:

public function action($actionType)
{
    //var_dump(new $actionType);

    if (!class_exists($actionType)) {
        //throw new Exception

    }

    if (!(new $actionType) instanceof ActionInterface) {
        ////throw new Exception
    }
    $actionType = new $actionType;
    echo $actionType->doAction();
}

But I am getting an error of class not found, however when I manually write the class name or manually append the namespace this way $actionType = __namespace__ . "\\$actionType";, then error goes. Why is that happening?

@stweb isn't creating an instance of a class without parentheses a short hand for not passing any parameters to the constructor? — rosengrenen, Aug 21 '16 at 09:15
Also, I would put the `$actionType = new $actionType;` between the if statements to avoid creating two instances. In the last if-statement you would do: `if (!$actionType instanceof ActionInterface) { }` — rosengrenen, Aug 21 '16 at 09:19
Replace if (!$actionType instanceof ActionInterface) with if (!($actionType instanceof ActionInterface)). About parentheses, I agree wuth @Rasmus Rosengren, you can skip it. — Ivnhal, Aug 21 '16 at 09:51
I suspect that PHP does not add default namespaces when processing variables in commands like 'new'. maybe interesting? [instantiate a class from a variable in PHP?](http://stackoverflow.com/questions/534159/instantiate-a-class-from-a-variable-in-php). Useful: manual: [Namespaces and dynamic language features](http://php.net/manual/en/language.namespaces.dynamic.php) . — Ryan Vincent, Aug 21 '16 at 10:47
@harry123 could you please show us your project structure and what the files/class you are trying to load look like — rosengrenen, Aug 21 '16 at 11:34
namespace of this class is something like this `namespace\subNamespace`, and folder structure is like this `app\namespace\subNamespace`, and from where I am loading the classes is index.php which is outside of the `app` directory. — Harry, Aug 21 '16 at 16:54

score 0 · Answer 1 · answered Aug 21 '16 at 10:00

0

Try this:

public function action($actionType) {
     //var_dump(new $actionType);
     if (!class_exists($actionType)) {
       //throw new Exception
     }
     $actionType = new $actionType;
     if (!($actionType instanceof ActionInterface)) {
        ////throw new Exception
     }

     echo $actionType->doAction();
}

answered Aug 21 '16 at 10:00

Ivnhal

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this doesn't make any difference. – Harry Aug 21 '16 at 16:26

Class not found, when trying to pass class name as string, namespace issue

1 Answers1