From 0cced24f6a4374c041d99a8bb082f4b7e626d717 Mon Sep 17 00:00:00 2001
From: Marc Zimmermann <marc.zimmermann@inf.ethz.ch>
Date: Mon, 11 Oct 2021 14:35:20 +0200
Subject: [PATCH] solve concurrency issue in WriteDocsToDatabase

writeQueue.poll gives null when empty (which is possible without snychronizing the method call). This leads to a crash in writeData
---
 .../ratschlab/deidentifier/workflows/WriteDocsToDatabase.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/deidentifier-pipeline/src/main/java/org/ratschlab/deidentifier/workflows/WriteDocsToDatabase.java b/deidentifier-pipeline/src/main/java/org/ratschlab/deidentifier/workflows/WriteDocsToDatabase.java
index ede8271..208bc19 100644
--- a/deidentifier-pipeline/src/main/java/org/ratschlab/deidentifier/workflows/WriteDocsToDatabase.java
+++ b/deidentifier-pipeline/src/main/java/org/ratschlab/deidentifier/workflows/WriteDocsToDatabase.java
@@ -51,7 +51,7 @@ public void doneHook() {
         }
     }
 
-    private void flushQueue() throws SQLException {
+    private synchronized void flushQueue() throws SQLException {
         List<Pair<String, Map<Object, Object>>> lst = new ArrayList<>();
 
         while (!writeQueue.isEmpty()) {