Extend API to add support for a limitied set of queries based on a ha…

…sh and a range condition, a common way that all advanced Key-Value stores allow querying in an effient way.

lib/Doctrine/KeyValueStore/EntityManager.php

@@ -43,11 +43,27 @@ public function __construct(Storage $storageDriver, Cache $cache, MappingDriver
         $this->storgeDriver = $storageDriver;
     }
 
-    public function find($className, $key)
+    public function find($className, $key, array $fields = null)
     {
         return $this->unitOfWork->reconsititute($className, $key);
     }
 
+    /**
+     * For key-value entities that have both a partition key and a range key of
+     * the combination (partition-key, range-key) you can use this operation
+     * to do queries for a partition of data.
+     *
+     * Some vendors don't support queries at all.
+     *
+     * @param string $className
+     * @param string $partitionKey
+     * @return Iterator
+     */
+    public function findRange($className, $partitionKey, array $conditions = array(), array $fields = array(), $limit = null, $offset null)
+    {
+
+    }
+
     public function persist($object)
     {
         $this->unitOfWork->scheduleForInsert($object);