the service factory method

gistfile1.php

<?php

namespace Bundle\ECommerce\ProductBundle\DependencyInjection;

use Symfony\Component\DependencyInjection\Extension\Extension;
use Doctrine\ODM\MongoDB\Query\Builder;

class ProductExtension extends Extension
{
    /**
     * Gets a closure that instanciates a paginator
     *
     * Call it like this:
     *   $builder = $this->get('ecommerce.repository.product')->getBuilder();
     *   $pagerFactory = $this->get('ecommerce.paginator.product.factory');
     *   $pager = \call_user_func($pagerFactory, $builder);*
     *
     * @static
     * @param  $paginatorClass the paginator class name
     * @param  $paginatorAdapterClass the adapter class name
     * @return Closure the closure to invoke with a Query builder as first argument
     */
    public static function getPaginatorFactory($paginatorClass, $paginatorAdapterClass)
    {
        return function(Builder $builder) use ($paginatorClass, $paginatorAdapterClass) {
            return new $paginatorClass(new $paginatorAdapterClass($builder));
        };
    }
    
    // some other stuff...
}

ProductController.php

<?php

namespace Bundle\ECommerce\ProductBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;

class ProductController extends Controller
{
    public function indexAction($page = 1)
    {
        $pager = $this->getPager();
        $pager->setCurrentPageNumber($this->get('request')->get('page', 1));
        
        return $this->render('ProductBundle:Product:index.php', array('pager' => $pager));
    }

    protected function getPager()
    {
        $builder = $this->get('ecommerce.repository.product')->getBuilder();
        $pagerFactory = $this->get('ecommerce.paginator.product.factory');
        return \call_user_func($pagerFactory, $builder);
    }
}

services.xml

<?xml version="1.0" encoding="UTF-8" ?>

<container xmlns="http://www.symfony-project.org/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.symfony-project.org/schema/dic/services http://www.symfony-project.org/schema/dic/services/services-1.0.xsd">

    <parameters>
        <parameter key="ecommerce.paginator.class">Zend\Paginator\Paginator</parameter>
        <parameter key="ecommerce.paginator.adapter.class">ZendPaginatorAdapter\DoctrineMongoDBAdapter</parameter>
    </parameters>

        <service id="ecommerce.paginator.product.factory" class="Bundle\ECommerce\ProductBundle\DependencyInjection\ProductExtension" shared="false" factory-method="getPaginatorFactory">
            <argument>%ecommerce.paginator.class%</argument>
            <argument>%ecommerce.paginator.adapter.class%</argument>
        </service>
</container>