The main entry point, helloworld.php, passes control to the controller, which handles performing the task that was specified in the request. At present, the component specific controller doesn't do anything more than the parent class already does, which is why the controller class is empty.
class HelloWorldController extends JControllerLegacy
{
}
JControllerLegacy is a base class for a Joomla Controller. In order to use controllers, you must extend this class in your component. Controllers are where you put all the actual code that provides basic functionality, such as rendering views.
__construct(array $config = array())
addModelPath(mixed $path, string $prefix = '') : void
addViewPath(mixed $path) : \JControllerLegacy
checkToken(string $method = 'post', boolean $redirect = true) : boolean
display(boolean $cachable = false, array $urlparams = array()) : \JControllerLegacy
execute(string $task) : mixed
getInstance(string $prefix, array $config = array()) : \JControllerLegacy
getModel(string $name = '', string $prefix = '', array $config = array()) : \JModelLegacy|boolean
getName() : string
getTask() : string
getTasks() : array
getView(string $name = '', string $type = '', string $prefix = '', array $config = array()) : \JViewLegacy
redirect() : boolean
registerDefaultTask(string $method) : \JControllerLegacy
registerTask(string $task, string $method) : \JControllerLegacy
setMessage(string $text, string $type = 'message') : string
setRedirect(string $url, string $msg = null, string $type = null) : \JControllerLegacy
unregisterTask(string $task) : \JControllerLegacy