class QueryFactory

class QueryFactory implements ContainerAwareInterface {
    use ContainerAwareTrait;
    use DeprecatedServicePropertyTrait;
    
    /**
     * {@inheritdoc}
     */
    protected $deprecatedProperties = [
        'entityManager' => 'entity.manager',
    ];
    
    /**
     * The entity type manager service.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * Constructs a QueryFactory object.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager service.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager) {
        $this->entityTypeManager = $entity_type_manager;
    }
    
    /**
     * Returns a query object for a given entity type.
     *
     * @param string $entity_type_id
     *   The entity type ID.
     * @param string $conjunction
     *   - AND: all of the conditions on the query need to match.
     *   - OR: at least one of the conditions on the query need to match.
     *
     * @return \Drupal\Core\Entity\Query\QueryInterface
     *   The query object that can query the given entity type.
     */
    public function get($entity_type_id, $conjunction = 'AND') {
        return $this->entityTypeManager
            ->getStorage($entity_type_id)
            ->getQuery($conjunction);
    }
    
    /**
     * Returns an aggregated query object for a given entity type.
     *
     * @param string $entity_type_id
     *   The entity type ID.
     * @param string $conjunction
     *   - AND: all of the conditions on the query need to match.
     *   - OR: at least one of the conditions on the query need to match.
     *
     * @return \Drupal\Core\Entity\Query\QueryAggregateInterface
     *   The aggregated query object that can query the given entity type.
     */
    public function getAggregate($entity_type_id, $conjunction = 'AND') {
        return $this->entityTypeManager
            ->getStorage($entity_type_id)
            ->getAggregateQuery($conjunction);
    }

}