Batched iterator for Magento collections

Batched Iterator for Magento collections

// This is how you would use it.  Pass in your collection
// along with an individual callback as well as a batch callback
Mage::getSingleton('stcore/resource_iterator_batched')->walk(
    $collection,
    array($this, 'batchIndividual'),
    array($this, 'batchAfter'),
    self::BATCH_SIZE
);

public function batchIndividual($model)
{
  // Do stuff with the $model
}

public function memberBatchAfter()
{
  // Do stuff with the batch.  For example if you're preparing a 
  // batch of records to pipe up to an API, here's where you 
  // do that.
}

Iterator_Batched

/**
 * Batched Iterator
 */
class ST_Core_Model_Resource_Iterator_Batched extends Varien_Object
{
    const DEFAULT_BATCH_SIZE = 250;

    /**
     * @param $collection Varien_Data_Collection
     * @param array $callback
     */
    public function walk($collection, array $callbackForIndividual, array $callbackAfterBatch, $batchSize = null)
    {
        if (!$batchSize) {
            $batchSize = self::DEFAULT_BATCH_SIZE;
        }

        $collection->setPageSize($batchSize);

        $currentPage = 1;
        $pages = $collection->getLastPageNumber();

        do {
            $collection->setCurPage($currentPage);
            $collection->load();
            foreach ($collection as $item) {
                call_user_func($callbackForIndividual, $item);
            }

            call_user_func($callbackAfterBatch);

            $currentPage++;
            $collection->clear();
        } while ($currentPage <= $pages);
    }
}