Symfony\Component\DependencyInjection\Definition::setFactory PHP Method

    public function setFactory($factory)
    {
        if (is_string($factory) && strpos($factory, '::') !== false) {
            $factory = explode('::', $factory, 2);
        }

        $this->factory = $factory;

        return $this;
    }

 /**
  * {@inheritdoc}
  */
 public function process(ContainerBuilder $container)
 {
     $analysis = $container->getParameter('es.analysis');
     $connections = $container->getParameter('es.connections');
     $managers = $container->getParameter('es.managers');
     $collector = $container->get('es.metadata_collector');
     foreach ($managers as $managerName => $manager) {
         if (!isset($connections[$manager['connection']])) {
             throw new InvalidConfigurationException('There is no ES connection with the name: ' . $manager['connection']);
         }
         $managerName = strtolower($managerName);
         $connection = $connections[$manager['connection']];
         $managerDefinition = new Definition($container->getParameter('es.manager.class'), [$managerName, $connection, $analysis, $manager]);
         $managerDefinition->setFactory([new Reference('es.manager_factory'), 'createManager']);
         $container->setDefinition(sprintf('es.manager.%s', $managerName), $managerDefinition);
         // Make es.manager.default as es.manager service.
         if ($managerName === 'default') {
             $container->setAlias('es.manager', 'es.manager.default');
         }
         $mappings = $collector->getMappings($manager['mappings']);
         // Building repository services.
         foreach ($mappings as $repositoryType => $repositoryDetails) {
             $repositoryDefinition = new Definition($container->getParameter('es.repository.class'), [$repositoryDetails['bundle'] . ':' . $repositoryDetails['class']]);
             $repositoryDefinition->setFactory([new Reference(sprintf('es.manager.%s', $managerName)), 'getRepository']);
             $repositoryId = sprintf('es.manager.%s.%s', $managerName, $repositoryType);
             if (strtolower(substr($repositoryType, -8)) === 'document') {
                 $container->setAlias(sprintf('es.manager.%s.%s', $managerName, substr($repositoryType, 0, strlen($repositoryType) - 8)), $repositoryId);
             }
             $container->setDefinition($repositoryId, $repositoryDefinition);
         }
     }
 }