From b1ab27a8fe2e06ab4d16f5b6f4ff107d694e19a6 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Leif=20=C3=85strand?= <leif@vaadin.com>
Date: Wed, 29 May 2013 10:43:07 +0300
Subject: [PATCH] Update broadcaster tutorial code

* Don't need to start a thread for broadcasting with the new UI.access
* Add @Push to the UI
* Use CopyOnWriteArrayList instead of synchronized methods

Change-Id: I63fad6977c1a3e504fc60445c3147b5a241c3132
---
 .../broadcastingmessages/Broadcaster.java     | 33 ++++---------------
 .../broadcastingmessages/BroadcasterUI.java   |  2 ++
 2 files changed, 9 insertions(+), 26 deletions(-)

diff --git a/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java
index 57ad0d97ba..78d0af6283 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java
@@ -16,44 +16,25 @@
 
 package com.vaadin.tests.minitutorials.broadcastingmessages;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 public class Broadcaster {
 
-    private static List<BroadcastListener> listeners = new ArrayList<BroadcastListener>();
+    private static final List<BroadcastListener> listeners = new CopyOnWriteArrayList<BroadcastListener>();
 
-    public synchronized static void register(BroadcastListener listener) {
+    public static void register(BroadcastListener listener) {
         listeners.add(listener);
     }
 
-    public synchronized static void unregister(BroadcastListener listener) {
+    public static void unregister(BroadcastListener listener) {
         listeners.remove(listener);
     }
 
-    private synchronized static List<BroadcastListener> getListeners() {
-        List<BroadcastListener> listenerCopy = new ArrayList<BroadcastListener>();
-        listenerCopy.addAll(listeners);
-        return listenerCopy;
-    }
-
     public static void broadcast(final String message) {
-        // Make a copy of the listener list while synchronized, can't be
-        // synchronized while firing the event or we would have to fire each
-        // event in a separate thread.
-        final List<BroadcastListener> listenerCopy = getListeners();
-
-        // We spawn another thread to avoid potential deadlocks with
-        // multiple UIs locked simultaneously
-        Thread eventThread = new Thread() {
-            @Override
-            public void run() {
-                for (BroadcastListener listener : listenerCopy) {
-                    listener.receiveBroadcast(message);
-                }
-            }
-        };
-        eventThread.start();
+        for (BroadcastListener listener : listeners) {
+            listener.receiveBroadcast(message);
+        }
     }
 
     public interface BroadcastListener {
diff --git a/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java
index 06ead20db3..68b5925f48 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java
@@ -1,5 +1,6 @@
 package com.vaadin.tests.minitutorials.broadcastingmessages;
 
+import com.vaadin.annotations.Push;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.tests.minitutorials.broadcastingmessages.Broadcaster.BroadcastListener;
 import com.vaadin.ui.Button;
@@ -10,6 +11,7 @@ import com.vaadin.ui.TextArea;
 import com.vaadin.ui.UI;
 import com.vaadin.ui.VerticalLayout;
 
+@Push
 public class BroadcasterUI extends UI implements BroadcastListener {
 
     @Override
-- 
2.39.5