src/main/java/com/kyndryl/platform/service/ItemsController.java

@@ -0,0 +1,70 @@
+package com.kyndryl.platform.service;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * A minimal but fully functional CRUD REST API for "items".
+ *
+ * Endpoints:
+ *   GET  /api/items       — list all items
+ *   POST /api/items       — create an item   { "name": "...", "description": "..." }
+ *   GET  /api/items/{id}  — get single item
+ *   PUT  /api/items/{id}  — update item
+ *   DELETE /api/items/{id} — delete item
+ *
+ * Health + metrics are exposed via Spring Actuator at /actuator/health and
+ * /actuator/prometheus (see application.yml).
+ */
+@RestController
+@RequestMapping("/api/items")
+public class ItemsController {
+
+    record Item(long id, String name, String description) {}
+
+    private final Map<Long, Item> store = new ConcurrentHashMap<>();
+    private final AtomicLong counter = new AtomicLong(1);
+
+    @GetMapping
+    public Collection<Item> list() {
+        return store.values();
+    }
+
+    @PostMapping
+    @ResponseStatus(HttpStatus.CREATED)
+    public Item create(@RequestBody Map<String, String> body) {
+        long id = counter.getAndIncrement();
+        Item item = new Item(id,
+            body.getOrDefault("name", "unnamed"),
+            body.getOrDefault("description", ""));
+        store.put(id, item);
+        return item;
+    }
+
+    @GetMapping("/{id}")
+    public Item get(@PathVariable long id) {
+        Item item = store.get(id);
+        if (item == null) throw new NoSuchElementException("Item not found: " + id);
+        return item;
+    }
+
+    @PutMapping("/{id}")
+    public Item update(@PathVariable long id, @RequestBody Map<String, String> body) {
+        if (!store.containsKey(id)) throw new NoSuchElementException("Item not found: " + id);
+        Item updated = new Item(id,
+            body.getOrDefault("name", store.get(id).name()),
+            body.getOrDefault("description", store.get(id).description()));
+        store.put(id, updated);
+        return updated;
+    }
+
+    @DeleteMapping("/{id}")
+    public Map<String, Object> delete(@PathVariable long id) {
+        store.remove(id);
+        return Map.of("deleted", id);
+    }
+}