I was tired of writing the same batch code all over again. At some point in the future this will be part of rixxi/basics or not...

Rixxi\Utils\Batch.php

<?php

namespace Rixxi\Utils;


class Batch implements \ArrayAccess
{

	/** @var int */
	private $limit;

	/** @var int */
	private $counter = 0;

	/** @var callable */
	private $callback;

	/** @var array */
	private $values = [];

	/** @var bool */
	private $finished = FALSE;


	/**
	 * @param callable $callback
	 * @param int $limit
	 */
	public function __construct(callable $callback, $limit = 9000)
	{
		$this->callback = $callback;
		$this->limit = $limit;
	}


	public function finish()
	{
		if ($this->finished) {
			throw new \Exception("Batch has already finished.");
		}

		call_user_func($this->callback, $this->values);
		$this->values = [];
	}


	public function offsetSet($index, $value)
	{
		if ($index !== NULL) {
			$this->unsupportedAccess();
		}

		$this->values[] = $value;
		if (++$this->counter === $this->limit) {
			call_user_func($this->callback, $this->values);
			$this->values = [];
			$this->counter = 0;
		}
	}


	public function offsetGet($index)
	{
		$this->unsupportedAccess();
	}


	public function offsetExists($index)
	{
		$this->unsupportedAccess();
	}


	public function offsetUnset($index)
	{
		$this->unsupportedAccess();
	}


	private function unsupportedAccess()
	{
		throw new \RuntimeException("You can only append to batch.");
	}

}