register doctrine extension in zf2 doctrine module

EntityManagerFactory.php

<?php

namespace Common\Service;

use Doctrine\ORM\EntityManager;
use DoctrineModule\Service\AbstractFactory;
use Zend\ServiceManager\ServiceLocatorInterface;

class EntityManagerFactory extends AbstractFactory
{
    /**
     * {@inheritDoc}
     * @return EntityManager
     */
    public function createService(ServiceLocatorInterface $sl)
    {
        /* @var $options \DoctrineORMModule\Options\EntityManager */
        $options    = $this->getOptions($sl, 'entitymanager');
        $connection = $sl->get($options->getConnection());
        $config     = $sl->get($options->getConfiguration());

        // initializing the resolver
        // @todo should actually attach it to a fetched event manager here, and not
        //       rely on its factory code
        $sl->get($options->getEntityResolver());
        
        // Table Prefix
        $tablePrefix = new \Common\DoctrineExtension\TablePrefix('prefix_');
        $evm = $connection->getEventManager();
        $evm->addEventListener(\Doctrine\ORM\Events::loadClassMetadata, $tablePrefix);

        return EntityManager::create($connection, $config, $evm);
    }

    /**
     * {@inheritDoc}
     */
    public function getOptionsClass()
    {
        return 'DoctrineORMModule\Options\EntityManager';
    }
}

module.config.php

<?php

return array(
   
    'doctrine_factories' => array(
        'entitymanager'            => 'Common\Service\EntityManagerFactory',
     ),
);

TablePrefix.php

<?php

namespace Common\DoctrineExtension;
use Doctrine\ORM\Event\LoadClassMetadataEventArgs;

class TablePrefix
{
    protected $prefix = '';

    public function __construct($prefix)
    {
        $this->prefix = (string) $prefix;
    }

    public function loadClassMetadata(LoadClassMetadataEventArgs $eventArgs)
    {
        $classMetadata = $eventArgs->getClassMetadata();
        $classMetadata->setTableName($this->prefix . $classMetadata->getTableName());
        foreach ($classMetadata->getAssociationMappings() as $fieldName => $mapping) {
            if ($mapping['type'] == \Doctrine\ORM\Mapping\ClassMetadataInfo::MANY_TO_MANY) {
                $mappedTableName = $classMetadata->associationMappings[$fieldName]['joinTable']['name'];
                $classMetadata->associationMappings[$fieldName]['joinTable']['name'] = $this->prefix . $mappedTableName;
            }
        }
    }

}