/**
* Checks if the stage contains some component or a given component
*
* @param string $name the name of the component, eg. 'role', 'glossary', 'datafield_text' etc.
* @param string $lang
* @param mlang_version $version
* @return bool
*/
public function has_component($name = null, $lang = null, mlang_version $version = null)
{
if (is_null($name) and is_null($lang) and is_null($version)) {
return !empty($this->components);
} else {
$cid = mlang_component::calculate_identifier($name, $lang, $version);
return isset($this->components[$cid]);
}
}