added lab15 ex2

src/lab15_observer/ex2/DigitalTimer.java

@@ -0,0 +1,15 @@
+package lab15_observer.ex2;
+
+public class DigitalTimer implements TimerObserver {
+    private final MyTimer timer;
+
+    public DigitalTimer(MyTimer timer) {
+        this.timer = timer;
+        timer.registerObserver(this);
+    }
+
+    @Override
+    public void update(int hours, int minutes, int seconds) {
+        System.out.printf("Time: %02d:%02d:%02d%n", hours, minutes, seconds);
+    }
+}