<?php
  
  namespace Guzzle\Batch;
  
  /**
   * Interface for efficiently transferring items in a queue using batches
   */
  interface BatchInterface
  {
      /**
       * Add an item to the queue
       *
       * @param mixed $item Item to add
       *
       * @return self
       */
      public function add($item);
  
      /**
       * Flush the batch and transfer the items
       *
       * @return array Returns an array flushed items
       */
      public function flush();
  
      /**
       * Check if the batch is empty and has further items to transfer
       *
       * @return bool
       */
      public function isEmpty();
  }