SEBSP-217 fixed bug within new code of last hot fix 1

Author: anhefti

src/main/java/ch/ethz/seb/sps/server/datalayer/dao/impl/ScreenshotDataLiveCacheDAOBatis.java

@@ -45,7 +45,13 @@ public ScreenshotDataLiveCacheDAOBatis(
     @Transactional
     public Result<ScreenshotDataLiveCacheRecord> createCacheEntry(String sessionUUID) {
         return Result
-            .tryCatch(() ->  screenshotDataLiveCacheRecordMapper.selectByPrimaryKey(createSlot(sessionUUID)))
+            .tryCatch(() -> {
+                Long slotId = createSlot(sessionUUID);
+                if (slotId == null) {
+                    throw new RuntimeException("Failed to get or create live cache slot for session: " + sessionUUID);
+                }
+                return screenshotDataLiveCacheRecordMapper.selectByPrimaryKey(slotId);
+            })
             .onError(TransactionHandler::rollback);
     }
 
@@ -114,7 +120,7 @@ private synchronized Long createSlot(String sessionUUID) {
 
             ScreenshotDataLiveCacheRecord rec = existing.get(0);
             if (rec.getIdLatestSsd() != null) {
-                return rec.getIdLatestSsd();
+                return rec.getId();
             } else {
                 // get value, update with value and return PK
                 Long lastScreenshotEntryId = getLastScreenshotEntryId(sessionUUID);

src/main/java/ch/ethz/seb/sps/server/servicelayer/impl/LiveProctoringCacheServiceImpl.java

@@ -129,7 +129,7 @@ public Long getLatestSSDataId(final String sessionUUID) {
             synchronized (this.cache) {
                 screenshotDataLiveCacheDAO
                         .createCacheEntry(sessionUUID)
-                        .onError(error -> log.error("Failed to create slot for session: {}", sessionUUID))
+                        .onError(error -> log.error("Failed to create slot for session: {}: error: {}", sessionUUID, error.getMessage()))
                         .onSuccess(rec -> cache.put(sessionUUID, rec.getIdLatestSsd()));
             }
         }