/**
* Get the backend, creates it if it does not exist
*
* @static
* @return BackendInterface
* @throws NoBackendException
*/
private static function getBackend()
{
if (!self::$backend) {
$backend = new ModuleBackend();
if ($backend->isAvailable()) {
self::$backend = $backend;
} else {
$backend = new CommandLineBackend();
if ($backend->isAvailable()) {
self::$backend = $backend;
} else {
$backend = new SeclibBackend();
if ($backend->isAvailable()) {
self::$backend = $backend;
}
}
}
if (!self::$backend) {
throw new NoBackendException('Unable to optain a backend, please check your PHP configuration');
}
}
return self::$backend;
}
