public function getIndexEngineIndices($criteria = null, ConnectionInterface $con = null)
    {
        $partial = $this->collIndexEngineIndicesPartial && !$this->isNew();
        if (null === $this->collIndexEngineIndices || null !== $criteria  || $partial) {
            if ($this->isNew() && null === $this->collIndexEngineIndices) {
                // return empty collection
                $this->initIndexEngineIndices();
            } else {
                $collIndexEngineIndices = ChildIndexEngineIndexQuery::create(null, $criteria)
                    ->filterByIndexEngineDriverConfiguration($this)
                    ->find($con);

                if (null !== $criteria) {
                    if (false !== $this->collIndexEngineIndicesPartial && count($collIndexEngineIndices)) {
                        $this->initIndexEngineIndices(false);

                        foreach ($collIndexEngineIndices as $obj) {
                            if (false == $this->collIndexEngineIndices->contains($obj)) {
                                $this->collIndexEngineIndices->append($obj);
                            }
                        }

                        $this->collIndexEngineIndicesPartial = true;
                    }

                    reset($collIndexEngineIndices);

                    return $collIndexEngineIndices;
                }

                if ($partial && $this->collIndexEngineIndices) {
                    foreach ($this->collIndexEngineIndices as $obj) {
                        if ($obj->isNew()) {
                            $collIndexEngineIndices[] = $obj;
                        }
                    }
                }

                $this->collIndexEngineIndices = $collIndexEngineIndices;
                $this->collIndexEngineIndicesPartial = false;
            }
        }

        return $this->collIndexEngineIndices;
    }