diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 1efb9ed..928b51d 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * This file is part of the LuneticsLocaleBundle package.
  *
@@ -7,6 +8,7 @@
  * For the full copyright and license information, please view the LICENSE
  * file that is distributed with this source code.
  */
+
 namespace Lunetics\LocaleBundle\DependencyInjection;
 
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
@@ -22,7 +24,7 @@ class Configuration implements ConfigurationInterface
     /**
      * {@inheritDoc}
      */
-    public function getConfigTreeBuilder()
+    public function getConfigTreeBuilder(): TreeBuilder
     {
         $treeBuilder = new TreeBuilder('lunetics_locale');
 
@@ -37,167 +39,173 @@ public function getConfigTreeBuilder()
         $rootNode
             ->fixXmlConfig('allowed_locale')
             ->children()
-                ->scalarNode('strict_mode')
-                    ->defaultFalse()
-                ->end()
-                ->scalarNode('strict_match')
-                    ->defaultFalse()
-                ->end()
-                ->booleanNode('disable_vary_header')->defaultFalse()->end()
-                ->arrayNode('allowed_locales')
-                    ->requiresAtLeastOneElement()
-                    ->prototype('scalar')->end()
-                ->end()
-                ->scalarNode('guessing_excluded_pattern')
-                    ->defaultNull()
-                ->end()
-                ->arrayNode('guessing_order')
-                    ->beforeNormalization()
-                        ->ifString()
-                            ->then(function ($v) { return array($v); })
-                    ->end()
-                    ->isRequired()
-                    ->requiresAtLeastOneElement()
-                    ->prototype('scalar')->end()
-                ->end()
-                ->arrayNode('router_guesser')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\RouterLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('browser_guesser')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\BrowserLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('cookie_guesser')
-                ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\CookieLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('session_guesser')
-                ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\SessionLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('query_guesser')
-                ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\QueryLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('subdomain_guesser')
-                ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\SubdomainLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('topleveldomain_guesser')
-                ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\TopleveldomainLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('domain_guesser')
-                ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('class')
-                            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\DomainLocaleGuesser')
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('cookie')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('set_on_change')->defaultTrue()->end()
-                        ->scalarNode('class')->defaultValue('Lunetics\LocaleBundle\Cookie\LocaleCookie')->end()
-                        ->scalarNode('name')->defaultValue('lunetics_locale')->end()
-                        ->scalarNode('ttl')->defaultValue('86400')->end()
-                        ->scalarNode('path')->defaultValue('/')->end()
-                        ->scalarNode('domain')->defaultValue(null)->end()
-                        ->scalarNode('secure')->defaultFalse()->end()
-                        ->scalarNode('httpOnly')->defaultTrue()->end()
-                     ->end()
-                ->end()
-                ->arrayNode('session')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('variable')->defaultValue('lunetics_locale')->end()
-                     ->end()
-                ->end()
-                ->arrayNode('query')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('parameter_name')->defaultValue('_locale')->end()
-                     ->end()
-                ->end()
-                ->arrayNode('subdomain')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('region_separator')->defaultValue('_')->end()
-                    ->end()
-                ->end()
-                ->arrayNode('topleveldomain')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->arrayNode('locale_map')
-                        ->useAttributeAsKey('name')
-                          ->prototype('scalar')->end()
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('domain')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->arrayNode('locale_map')
-                        ->normalizeKeys(false)
-                        ->useAttributeAsKey('name')
-                          ->prototype('scalar')->end()
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('form')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->booleanNode('languages_only')->defaultTrue()->end()
-                        ->booleanNode('strict_mode')->defaultFalse()->end()
-                    ->end()
-                ->end()
-                ->arrayNode('switcher')
-                    ->addDefaultsIfNotSet()
-                    ->children()
-                        ->scalarNode('template')->defaultValue('links')->end()
-                        ->booleanNode('show_current_locale')->defaultFalse()->end()
-                        ->scalarNode('redirect_to_route')->defaultNull()->end()
-                        ->scalarNode('redirect_statuscode')->defaultValue('302')->end()
-                        ->booleanNode('use_controller')->defaultFalse()->end()
-                        ->booleanNode('use_referrer')->defaultTrue()->end()
-                    ->end()
-                    ->validate()
-                        ->ifTrue(function($v) { return is_null($v['redirect_to_route']);})
-                            ->thenInvalid('You need to specify a default fallback route for the use_controller configuration')
-                        ->ifTrue(function($v) use ($validStatuscodes) { return !in_array(intval($v['redirect_statuscode']), $validStatuscodes);})
-                            ->thenInvalid(sprintf("Invalid HTTP statuscode. Available statuscodes for redirection are:\n\n%s \n\nSee reference for HTTP status codes", implode(", ",$validStatuscodes)))
-                    ->end()
-                ->end()
+            ->scalarNode('strict_mode')
+            ->defaultFalse()
+            ->end()
+            ->scalarNode('strict_match')
+            ->defaultFalse()
+            ->end()
+            ->booleanNode('disable_vary_header')->defaultFalse()->end()
+            ->arrayNode('allowed_locales')
+            ->requiresAtLeastOneElement()
+            ->prototype('scalar')->end()
+            ->end()
+            ->scalarNode('guessing_excluded_pattern')
+            ->defaultNull()
+            ->end()
+            ->arrayNode('guessing_order')
+            ->beforeNormalization()
+            ->ifString()
+            ->then(function ($v) {
+                return array($v);
+            })
+            ->end()
+            ->isRequired()
+            ->requiresAtLeastOneElement()
+            ->prototype('scalar')->end()
+            ->end()
+            ->arrayNode('router_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\RouterLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('browser_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\BrowserLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('cookie_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\CookieLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('session_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\SessionLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('query_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\QueryLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('subdomain_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\SubdomainLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('topleveldomain_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\TopleveldomainLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('domain_guesser')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('class')
+            ->defaultValue('Lunetics\LocaleBundle\LocaleGuesser\DomainLocaleGuesser')
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('cookie')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('set_on_change')->defaultTrue()->end()
+            ->scalarNode('class')->defaultValue('Lunetics\LocaleBundle\Cookie\LocaleCookie')->end()
+            ->scalarNode('name')->defaultValue('lunetics_locale')->end()
+            ->scalarNode('ttl')->defaultValue('86400')->end()
+            ->scalarNode('path')->defaultValue('/')->end()
+            ->scalarNode('domain')->defaultValue(null)->end()
+            ->scalarNode('secure')->defaultFalse()->end()
+            ->scalarNode('httpOnly')->defaultTrue()->end()
+            ->end()
+            ->end()
+            ->arrayNode('session')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('variable')->defaultValue('lunetics_locale')->end()
+            ->end()
+            ->end()
+            ->arrayNode('query')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('parameter_name')->defaultValue('_locale')->end()
+            ->end()
+            ->end()
+            ->arrayNode('subdomain')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('region_separator')->defaultValue('_')->end()
+            ->end()
+            ->end()
+            ->arrayNode('topleveldomain')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->arrayNode('locale_map')
+            ->useAttributeAsKey('name')
+            ->prototype('scalar')->end()
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('domain')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->arrayNode('locale_map')
+            ->normalizeKeys(false)
+            ->useAttributeAsKey('name')
+            ->prototype('scalar')->end()
+            ->end()
+            ->end()
+            ->end()
+            ->arrayNode('form')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->booleanNode('languages_only')->defaultTrue()->end()
+            ->booleanNode('strict_mode')->defaultFalse()->end()
+            ->end()
+            ->end()
+            ->arrayNode('switcher')
+            ->addDefaultsIfNotSet()
+            ->children()
+            ->scalarNode('template')->defaultValue('links')->end()
+            ->booleanNode('show_current_locale')->defaultFalse()->end()
+            ->scalarNode('redirect_to_route')->defaultNull()->end()
+            ->scalarNode('redirect_statuscode')->defaultValue('302')->end()
+            ->booleanNode('use_controller')->defaultFalse()->end()
+            ->booleanNode('use_referrer')->defaultTrue()->end()
+            ->end()
+            ->validate()
+            ->ifTrue(function ($v) {
+                return is_null($v['redirect_to_route']);
+            })
+            ->thenInvalid('You need to specify a default fallback route for the use_controller configuration')
+            ->ifTrue(function ($v) use ($validStatuscodes) {
+                return !in_array(intval($v['redirect_statuscode']), $validStatuscodes);
+            })
+            ->thenInvalid(sprintf("Invalid HTTP statuscode. Available statuscodes for redirection are:\n\n%s \n\nSee reference for HTTP status codes", implode(", ", $validStatuscodes)))
+            ->end()
+            ->end()
             ->end();
 
         return $treeBuilder;