private function validateRequiredParameters()
    {
        $ret = true;
        foreach ($this->parameterCluster->prefixes as $prefix => $parameters) {
            foreach ($parameters as $parameterClosure) {
                if ($parameterClosure->required) {
                    if (! in_array(
                        $parameterClosure
                        ->prefix.
                        $parameterClosure
                        ->parameterName,
                        $this->argv
                    )) {
                        $aliasFound = false;
                        foreach ($parameterClosure->aliases as $prefix => $alias) {
                            if (in_array($prefix.$alias, $this->argv)) {
                                $aliasFound = true;
                                break;
                            }
                        }
                        if (! $aliasFound) {
                            $ret = $parameterClosure;
                            break 2;
                        }
                    }
                }
            }
        }

        return $ret;
    }