Joins with Typo3 Extbase

Joins mit Extbase Vers 1.0

        // Erstmal: Selector erweitern:
        // Selector 1 ist das aktuelle Model:
        $selector1 = $query->getSource();
        $selector1_JoinField = "company.postcode";
        // QomFactory holen
        //$qomFactory = $this->persistenceManager->getBackend()->getQOMFactory();
        $backend = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Extbase\\Persistence\\Generic\\Backend');
        $qomFactory = $backend->getQomFactory();
        // Selector 2 zusammenstellen:
        $model = null;
        $tableName = "postcode_test";
        $selector2_JoinField = "uid";
        $selector2 = $qomFactory->selector($model, $tableName);
        var_dump($selector2);
        // Selectoren Joinen:
        $joinCondition = $qomFactory->equiJoinCondition(
            $selector1->getSelectorName(), $selector1_JoinField,
            $selector2->getSelectorName(), $selector2_JoinField
        );

        $query->setSource(
            $qomFactory->join(
                $selector2,
                $selector1,
                // For the List of Joins,visit : http://typo3.org/api/typo3cms/_query_interface_8php_source.html
                \TYPO3\CMS\Extbase\Persistence\Generic\Qom\QueryObjectModelConstantsInterface::JCR_JOIN_TYPE_LEFT_OUTER,
                $joinCondition)
        );