FluidTYPO3\Flux\Controller\AbstractFluxController::hasSubControllerActionOnForeignController PHP Method

    protected function hasSubControllerActionOnForeignController($extensionName, $controllerName, $actionName)
    {
        $potentialControllerClassName = $this->configurationService->getResolver()->resolveFluxControllerClassNameByExtensionKeyAndAction($extensionName, $actionName, $controllerName);
        $isForeign = $extensionName !== $this->extensionName;
        $isValidController = class_exists($potentialControllerClassName);
        return TRUE === $isForeign && TRUE === $isValidController;
    }