src/Validation/Adapter/ZendFrameworkAdapter.php
public function isValid($value)
    {
        if (($this->allowEmpty && empty($value)) || $this->validator->isValid($value)) {
            $this->errorMessage = '';
            return true;
        }
        $this->errorMessage = (empty($this->label) ? '' : "{$this->label}: ") . join(' / ', $this->validator->getMessages());
        return false;
    }
public function isValid($value)
    {
        if (($this->allowEmpty && empty($value)) || $this->validator->isValid($value)) {
            $this->errorMessage = '';
            return true;
        }
        $this->errorMessage = (empty($this->label) ? '' : "{$this->label}: ") . join(' / ', $this->validator->getMessages());
        return false;
    }
{@inheritdoc}