From 47657918b484fad60ac4062177cfeb569275d3d3 Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Sat, 13 Aug 2022 15:19:54 +0200
Subject: [PATCH] =?utf8?q?GR=C3=9CN:=20Erwartungen=20implementiert?=
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---
 .../de/juplo/kafka/AdderBusinessLogic.java     | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/main/java/de/juplo/kafka/AdderBusinessLogic.java b/src/main/java/de/juplo/kafka/AdderBusinessLogic.java
index 2e3d126..a3848c4 100644
--- a/src/main/java/de/juplo/kafka/AdderBusinessLogic.java
+++ b/src/main/java/de/juplo/kafka/AdderBusinessLogic.java
@@ -1,13 +1,31 @@
 package de.juplo.kafka;
 
 
+import java.util.HashMap;
+import java.util.Map;
+
+
 public class AdderBusinessLogic
 {
+  private final Map<String, Long> state;
+
+
   public AdderBusinessLogic()
   {
+    this(new HashMap<>());
   }
 
+  public AdderBusinessLogic(Map<String, Long> state)
+  {
+    this.state = state;
+  }
+
+
   public synchronized void startSum(String user)
   {
+    if (state.containsKey(user))
+      throw new IllegalStateException("Sumation for " + user + " already in progress, state: " + state.get(user));
+
+    state.put(user, 0l);
   }
 }
-- 
2.20.1