update:demo4

com/study/demo4/HomeController.java

@@ -0,0 +1,21 @@
+package com.study.demo4;
+
+import java.util.ArrayList;
+import java.util.List;
+
+class HomeController {
+  private List<SmartDevice> devices = new ArrayList<>();
+
+  public void addDevice(SmartDevice device) {
+    devices.add(device);
+  }
+
+  public String getDeviceStatus(String name) {
+    for (SmartDevice device : devices) {
+      if (device.getStatus().contains(name)) {
+        return device.getStatus();
+      }
+    }
+    return "Device not found";
+  }
+}