DependencyInjection/Configuration.php
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $treeBuilder->root('rss_client')
            ->children()
                ->arrayNode('cache')
                    ->addDefaultsIfNotSet()
                    ->children()
                        ->scalarNode('adapter')
                            ->defaultValue('Desarrolla2\Cache\Adapter\NotCache')
                            ->cannotBeEmpty()
                        ->end()
                        ->scalarNode('ttl')
                            ->defaultValue('3600')
                            ->cannotBeEmpty()
                        ->end()
                    ->end()
                ->end()
                ->arrayNode('processors')
                    ->prototype('scalar')
                    ->end()
                ->end()
                ->arrayNode('channels')
                    ->useAttributeAsKey('id')
                    ->info('RSS Client Channels Configuration')
                    ->treatNullLike(array())
                        ->prototype('array')
                        ->treatNullLike(array())
                            ->prototype('scalar')
                            ->treatNullLike(null)
                            ->end()
                        ->end()
                    ->end()
                ->end()
            ->end()
            ;
        return $treeBuilder;
    }
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $treeBuilder->root('rss_client')
            ->children()
                ->arrayNode('cache')
                    ->addDefaultsIfNotSet()
                    ->children()
                        ->scalarNode('adapter')
                            ->defaultValue('Desarrolla2\Cache\Adapter\NotCache')
                            ->cannotBeEmpty()
                        ->end()
                        ->scalarNode('ttl')
                            ->defaultValue('3600')
                            ->cannotBeEmpty()
                        ->end()
                    ->end()
                ->end()
                ->arrayNode('processors')
                    ->prototype('scalar')
                    ->end()
                ->end()
                ->arrayNode('channels')
                    ->useAttributeAsKey('id')
                    ->info('RSS Client Channels Configuration')
                    ->treatNullLike(array())
                        ->prototype('array')
                        ->treatNullLike(array())
                            ->prototype('scalar')
                            ->treatNullLike(null)
                            ->end()
                        ->end()
                    ->end()
                ->end()
            ->end()
            ;
        return $treeBuilder;
    }
{@inheritDoc}