/**
 * DataProvider constructor.
 * @param $name
 * @param $primaryFieldName
 * @param $requestFieldName
 * @param array $meta
 * @param array $data
 */
public function __construct(
    $name,
    $primaryFieldName,
    $requestFieldName,
    array $meta = [],
    array $data = []
) {
    $objectManager = MagentoFrameworkAppObjectManager::getInstance();
    $product = MagentoCatalogModelProduct;
    $this->collection = $objectManager->create("CommercersStockLogModelStockLog")->getCollection();
    $this->collection->getSelect()->reset(Zend_Db_Select::COLUMNS);
    $this->collection->getSelect()->join(array('catalog_product_entity' => $product), 'main_table.product_id = catalog_product_entity.entity_id');
    parent::__construct($name, $primaryFieldName, $requestFieldName, $meta, $data);

}

public function getData()
{
    $data = [];
    foreach($this->getCollection()->getItems() as $item){
        $data[$item->getId()] = array('stocklog_columns' => $item->getData());
    }
    return $data;
}