From 8828b2f4e82e0b487b16417831b006d184e00e11 Mon Sep 17 00:00:00 2001
From: anhefti <andreas.hefti@let.ethz.ch>
Date: Mon, 14 Nov 2022 16:24:58 +0100
Subject: [PATCH] Fixed Exam quiz data update for additional attributes (delete
 null)

---
 .../servicelayer/dao/impl/ExamDAOImpl.java    | 25 +++++++++++++------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/dao/impl/ExamDAOImpl.java b/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/dao/impl/ExamDAOImpl.java
index 847490b8..d1600902 100644
--- a/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/dao/impl/ExamDAOImpl.java
+++ b/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/dao/impl/ExamDAOImpl.java
@@ -749,13 +749,24 @@ public class ExamDAOImpl implements ExamDAO {
             additionalAttributes.put(QuizData.QUIZ_ATTR_START_URL, quizData.startURL);
         }
 
-        if (!additionalAttributes.isEmpty()) {
-            this.additionalAttributesDAO.saveAdditionalAttributes(
-                    EntityType.EXAM,
-                    examId,
-                    additionalAttributes)
-                    .getOrThrow();
-        }
+        additionalAttributes.entrySet().forEach(entry -> {
+            final String value = entry.getValue();
+            if (value == null) {
+                this.additionalAttributesDAO.delete(
+                        EntityType.EXAM,
+                        examId,
+                        entry.getKey());
+            } else {
+                this.additionalAttributesDAO.saveAdditionalAttribute(
+                        EntityType.EXAM,
+                        examId,
+                        entry.getKey(),
+                        value)
+                        .onError(error -> log.error("Failed to save additional quiz attribute: {}",
+                                entry.getKey(),
+                                error));
+            }
+        });
 
         return quizData;
     }