X-Git-Url: http://juplo.de/gitweb/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FAdderBusinessLogic.java;fp=src%2Fmain%2Fjava%2Fde%2Fjuplo%2Fkafka%2FAdderBusinessLogic.java;h=c0c19a55ef2085014a783a7ce591d1939356cbf9;hb=17360fbf2f944f6818c748ed1235264b7d8d28a4;hp=0000000000000000000000000000000000000000;hpb=ae8d6e6f4144cdef108b8d13e005b0f869599a77;p=demos%2Fkafka%2Ftraining

diff --git a/src/main/java/de/juplo/kafka/AdderBusinessLogic.java b/src/main/java/de/juplo/kafka/AdderBusinessLogic.java
new file mode 100644
index 0000000..c0c19a5
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/AdderBusinessLogic.java
@@ -0,0 +1,50 @@
+package de.juplo.kafka;
+
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+
+public class AdderBusinessLogic
+{
+  private final Map<String, AdderResult> state;
+
+
+  public AdderBusinessLogic()
+  {
+    this(new HashMap<>());
+  }
+
+  public AdderBusinessLogic(Map<String, AdderResult> state)
+  {
+    this.state = state;
+  }
+
+
+  public synchronized Optional<Long> getSum(String user)
+  {
+    return Optional.ofNullable(state.get(user)).map(result -> result.sum);
+  }
+
+  public synchronized void addToSum(String user, Integer value)
+  {
+    if (value == null || value < 1)
+      throw new IllegalArgumentException("Not a positive number: " + value);
+
+    long sum =
+        Optional
+            .ofNullable(state.get(user))
+            .map(result -> result.sum)
+            .orElse(0l);
+    state.put(user, new AdderResult(value, sum + value));
+  }
+
+  public synchronized AdderResult calculate(String user)
+  {
+    if (!state.containsKey(user))
+      throw new IllegalStateException("No sumation for " + user + " in progress");
+
+    return state.remove(user);
+  }
+}