Question

I am right now working with the Doctrine 2 stuff and landed upon the Doctrine modules for validations like ObjectExists.php and NoObjectExists.php.

My question is that from the original code which can be found here.

    /**
     * Constructor
     *
     * @param array $options required keys are `object_repository`, which must be an instance of
     * Doctrine\Common\Persistence\ObjectRepository, and `fields`, with either
     * a string or an array of strings representing the fields to be matched by the validator.
     * @throws \Zend\Validator\Exception\InvalidArgumentException
     */
    public function __construct(array $options)
    {
        if (!isset($options['object_repository']) || !$options['object_repository'] instanceof ObjectRepository) {
            if (!array_key_exists('object_repository', $options)) {
                $provided = 'nothing';
            } else {
                if (is_object($options['object_repository'])) {
                    $provided = get_class($options['object_repository']);
                } else {
                    $provided = getType($options['object_repository']);
                }
            }

            throw new Exception\InvalidArgumentException(sprintf(
                'Option "object_repository" is required and must be an instance of'
                    . ' Doctrine\Common\Persistence\ObjectRepository, %s given',
                $provided
            ));
        }

        $this->objectRepository = $options['object_repository'];

        if (!isset($options['fields'])) {
            throw new Exception\InvalidArgumentException(
                'Key `fields` must be provided and be a field or a list of fields to be used when searching for'
                    . ' existing instances'
            );
        }

        $this->fields = $options['fields'];
        $this->validateFields();

        parent::__construct($options);
    }

I cannot get the fact that here it is mentioned “$options required keys are object_repository, which must be an instance of Doctrine\Common\Persistence\ObjectRepository“

Since Doctrine\Common\Persistence\ObjectRepository is an interface, how should I decode that statement?

Or in other words how can I call this constructor of ObjectsExists class and pass object_repository, which must be an instance of Doctrine\Common\Persistence\ObjectRepository?

Can somebody throw some light on this, I’m getting into this stuff, so do not be harsh on my question.

Thanks

Answer 1

Since Doctrine\Common\Persistence\ObjectRepository is an interface you cannot instantiate it but you can implement it.

class MyObjectRepository implements Doctrine\Common\Persistence\ObjectRepository
{
    // ...
}

Now every instance of MyObjectRepository will met the object_repository requirement of ObjectsExists.

new ObjectsExists(array(
    'object_repository' => new MyObjectRepository(),
    // ...
));

---

More about instanceof:

instanceof is used to determine whether a PHP variable is an instantiated object of a certain class.

instanceof can also be used to determine whether a variable is an instantiated object of a class that inherits from a parent class.

instanceof can also be used to determine whether a variable is an instantiated object of a class that implements an interface.