Add kafka-streams module: fraud detection topology tested with TopologyTestDriver

Similarity scoring, a 5-minute windowed count that alerts once, and a KTable blocklist join, with the Spring wiring on Spring Boot 4.1.1 and Kafka Streams 4.2.1. Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01RjfyTgmERTWLqzafu34Cth
2026-10-14 06:44:56 +00:00
parent 5db56e70a0
commit 59fcdbe079
19 changed files with 520 additions and 0 deletions
@@ -0,0 +1,15 @@
+package com.ankurm.streams;
+
+/** A card transaction. */
+public record Txn(String card, double amount, int hour, String category) {
+
+    /** Wire format: {@code card,amount,hour,category}. Plain text keeps the serde trivial to read. */
+    public String encode() {
+        return card + "," + amount + "," + hour + "," + category;
+    }
+
+    public static Txn decode(String s) {
+        String[] p = s.split(",", 4);
+        return new Txn(p[0], Double.parseDouble(p[1]), Integer.parseInt(p[2]), p[3]);
+    }
+}