Merge pull request #45 from Shaked/patch-1

added LogicException

Strategy/ObjectCollection.php

@@ -30,6 +30,10 @@ class ObjectCollection
      */
     public function sort()
     {
+        if (!$this->comparator){ 
+            throw new \LogicException("Comparator is not set");    
+        }
+        
         $callback = array($this->comparator, 'compare');
         uasort($this->elements, $callback);