Improved update time when refreshing/connecting to websocket by cachi…

…ng the last message and sending it upon connection from a client.

src/main/java/com/jitterted/mobreg/adapter/out/websocket/WebSocketBroadcaster.java

@@ -13,31 +13,37 @@
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 
 @Component
 public class WebSocketBroadcaster extends TextWebSocketHandler implements Broadcaster {
     private static final Logger LOGGER = LoggerFactory.getLogger(WebSocketBroadcaster.class);
 
     private final Map<String, WebSocketSession> sessionMap = new ConcurrentHashMap<>();
+    private Optional<TextMessage> currentTextMessage = Optional.empty();
 
     @Override
     public void sendCurrentTimer(EnsembleTimer ensembleTimer) {
         String html = TimerToHtmlTransformer.htmlFor(ensembleTimer);
         TextMessage textMessage = new TextMessage(html);
-        sessionMap.values().forEach(session -> {
-            try {
-                session.sendMessage(textMessage);
-            } catch (IOException e) {
-                throw new RuntimeException(e);
-            }
-        });
+        currentTextMessage = Optional.of(textMessage);
+        sessionMap.values().forEach(session -> sendMessageViaWebSocket(session, textMessage));
     }
 
     @Override
     public void afterConnectionEstablished(WebSocketSession session) throws Exception {
         LOGGER.info("Websocket connection established, session ID: {}, session remote address: {}", session.getId(), session.getRemoteAddress());
         sessionMap.put(session.getId(), session);
+        currentTextMessage.ifPresent(message -> sendMessageViaWebSocket(session, message));
+    }
+
+    private void sendMessageViaWebSocket(WebSocketSession session, TextMessage message) {
+        try {
+            session.sendMessage(message);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     @Override