Fixed bugs

classes/ErrorHandler.php

@@ -9,7 +9,7 @@ namespace CloudObjects\PhpMAE;
 use Slim\Psr7\Response;
 use Slim\ResponseEmitter;
 use ML\JsonLD\Node;
-use CloudObjects\SDK\ObjectRetriever;
+use CloudObjects\SDK\ObjectRetriever, CloudObjects\SDK\Constants;
 
 class ErrorHandler {
 
@@ -22,7 +22,7 @@ class ErrorHandler {
             $message = substr($error['message'], 0,  strpos($error['message'], ' in /'));
             $response = (new Response(500))->withHeader('Content-Type', 'text/plain');
             $response->getBody()->write("Error in implementation of <".$object->getId()."> at revision "
-                . $object->getProperty(ObjectRetriever::REVISION_PROPERTY)->getValue()
+                . $object->getProperty(Constants::PROPERTY_REVISION)->getValue()
                 . ":\n".$message);
             return $response;
         });