Sources for the "Broadcasting messages to other users" tutorial

Change-Id: I1408d2b4c33bb51393867b2a089035699a5af756

2 files changed, 121 insertions, 0 deletions

diff --git a/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java
new file mode 100644
index 0000000000..e355cd1dbd
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+++ b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/Broadcaster.java
@@ -0,0 +1,63 @@
+package com.vaadin.tests.minitutorials.broadcastingmessages;
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Broadcaster {
+
+    private static List<BroadcastListener> listeners = new ArrayList<BroadcastListener>();
+
+    public synchronized static void register(BroadcastListener listener) {
+        listeners.add(listener);
+    }
+
+    public synchronized 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();
+    }
+
+    public interface BroadcastListener {
+        public void receiveBroadcast(String message);
+    }
+
+}
diff --git a/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java
new file mode 100644
index 0000000000..80c847250d
--- /dev/null
+++ b/uitest/src/com/vaadin/tests/minitutorials/broadcastingmessages/BroadcasterUI.java
@@ -0,0 +1,58 @@
+package com.vaadin.tests.minitutorials.broadcastingmessages;
+
+
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.minitutorials.broadcastingmessages.Broadcaster.BroadcastListener;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.Button.ClickEvent;
+import com.vaadin.ui.Notification;
+import com.vaadin.ui.Notification.Type;
+import com.vaadin.ui.TextArea;
+import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
+
+public class BroadcasterUI extends UI implements BroadcastListener {
+
+    @Override
+    protected void init(VaadinRequest request) {
+        final VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
+        final TextArea message = new TextArea("",
+                "The system is going down for maintenance in 10 minutes");
+        layout.addComponent(message);
+
+        final Button button = new Button("Broadcast");
+        layout.addComponent(button);
+        button.addClickListener(new Button.ClickListener() {
+            @Override
+            public void buttonClick(ClickEvent event) {
+                Broadcaster.broadcast(message.getValue());
+            }
+        });
+
+        // Register broadcast listener
+        Broadcaster.register(this);
+    }
+
+    @Override
+    public void detach() {
+        Broadcaster.unregister(this);
+        super.detach();
+    }
+
+    @Override
+    public void receiveBroadcast(final String message) {
+        runSafely(new Runnable() {
+            @Override
+            public void run() {
+                Notification n = new Notification("Message received", message,
+                        Type.TRAY_NOTIFICATION);
+                n.show(getPage());
+            }
+        });
+
+    }
+
+}
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