Initial support for toggling push on the fly (#11506)

Still missing is the ability to load vaadinPush.js if it has not yet
been loaded.

Change-Id: Ibe3596c38a7c4e3432b0396072866ee3072e6d30

4 files changed, 79 insertions, 19 deletions

diff --git a/server/src/com/vaadin/server/communication/AtmospherePushConnection.java b/server/src/com/vaadin/server/communication/AtmospherePushConnection.java
index 9b98153a23..a5025e2356 100644
--- a/server/src/com/vaadin/server/communication/AtmospherePushConnection.java
+++ b/server/src/com/vaadin/server/communication/AtmospherePushConnection.java
@@ -117,4 +117,12 @@ public class AtmospherePushConnection implements Serializable, PushConnection {
     protected AtmosphereResource getResource() {
         return resource;
     }
+
+    @Override
+    public void disconnect() {
+        resource.resume();
+        assert !resource.getBroadcaster().getAtmosphereResources()
+                .contains(resource);
+        resource = null;
+    }
 }
diff --git a/server/src/com/vaadin/server/communication/PushConnection.java b/server/src/com/vaadin/server/communication/PushConnection.java
index 590219b1b5..eecf4d93a4 100644
--- a/server/src/com/vaadin/server/communication/PushConnection.java
+++ b/server/src/com/vaadin/server/communication/PushConnection.java
@@ -35,4 +35,9 @@ public interface PushConnection {
      */
     public void push();
 
+    /**
+     * Disconnects the connection.
+     */
+    public void disconnect();
+
 }
\ No newline at end of file
diff --git a/server/src/com/vaadin/server/communication/PushHandler.java b/server/src/com/vaadin/server/communication/PushHandler.java
index a9e6c17751..bdc8c723a5 100644
--- a/server/src/com/vaadin/server/communication/PushHandler.java
+++ b/server/src/com/vaadin/server/communication/PushHandler.java
@@ -38,6 +38,7 @@ import com.vaadin.server.VaadinServletRequest;
 import com.vaadin.server.VaadinServletService;
 import com.vaadin.server.VaadinSession;
 import com.vaadin.server.WebBrowser;
+import com.vaadin.shared.communication.PushMode;
 import com.vaadin.ui.UI;
 
 /**
@@ -138,6 +139,46 @@ public class PushHandler implements AtmosphereHandler {
         }
     };
 
+    /**
+     * Callback used when a connection is closed by the client.
+     */
+    PushEventCallback disconnectCallback = new PushEventCallback() {
+        @Override
+        public void run(AtmosphereResource resource, UI ui) throws IOException {
+            PushMode pushMode = ui.getPushMode();
+            AtmospherePushConnection pushConnection = getConnectionForUI(ui);
+
+            String id = resource.uuid();
+
+            if (pushConnection == null) {
+                getLogger()
+                        .log(Level.WARNING,
+                                "Could not find push connection to close: {0} with transport {1}",
+                                new Object[] { id, resource.transport() });
+            } else {
+                if (!pushMode.isEnabled()) {
+                    /*
+                     * The client is expected to close the connection after push
+                     * mode has been set to disabled, just clean up some stuff
+                     * and be done with it
+                     */
+                    getLogger().log(Level.FINEST,
+                            "Connection closed for resource {0}", id);
+                } else {
+                    /*
+                     * Unexpected cancel, e.g. if the user closes the browser
+                     * tab.
+                     */
+                    getLogger()
+                            .log(Level.FINE,
+                                    "Connection unexpectedly closed for resource {0} with transport {1}",
+                                    new Object[] { id, resource.transport() });
+                }
+                ui.setPushConnection(null);
+            }
+        }
+    };
+
     private static final String LONG_PADDING;
 
     static {
@@ -234,10 +275,7 @@ public class PushHandler implements AtmosphereHandler {
 
         String id = resource.uuid();
         if (event.isCancelled()) {
-            // The client closed the connection.
-            // TODO Do some cleanup
-            getLogger().log(Level.FINER, "Connection closed for resource {0}",
-                    id);
+            callWithUi(resource, disconnectCallback);
         } else if (event.isResuming()) {
             // A connection that was suspended earlier was resumed (committed to
             // the client.) Should only happen if the transport is JSONP or
diff --git a/server/src/com/vaadin/ui/UI.java b/server/src/com/vaadin/ui/UI.java
index 4eff7645e2..e1646a5ac5 100644
--- a/server/src/com/vaadin/ui/UI.java
+++ b/server/src/com/vaadin/ui/UI.java
@@ -130,8 +130,6 @@ public abstract class UI extends AbstractSingleComponentContainer implements
      */
     private int scrollLeft = 0;
 
-    private PushMode pushMode;
-
     private UIServerRpc rpc = new UIServerRpc() {
         @Override
         public void click(MouseEventDetails mouseDetails) {
@@ -1189,11 +1187,19 @@ public abstract class UI extends AbstractSingleComponentContainer implements
      * Sets the internal push connection object used by this UI. This method
      * should only be called by the framework.
      */
-    public void setPushConnection(PushConnection connection) {
-        assert pushConnection == null;
-        assert connection != null;
-        pushConnection = connection;
-        if (hasPendingPush) {
+    public void setPushConnection(PushConnection pushConnection) {
+        assert (pushConnection != null) == (getPushMode().isEnabled());
+
+        if (pushConnection == this.pushConnection) {
+            return;
+        }
+
+        if (this.pushConnection != null) {
+            this.pushConnection.disconnect();
+        }
+
+        this.pushConnection = pushConnection;
+        if (pushConnection != null && hasPendingPush) {
             hasPendingPush = false;
             pushConnection.push();
         }
@@ -1232,12 +1238,12 @@ public abstract class UI extends AbstractSingleComponentContainer implements
      * @return The push mode.
      */
     public PushMode getPushMode() {
-        return pushMode;
+        return getState(false).pushMode;
     }
 
     /**
      * Sets the mode of bidirectional ("push") communication that should be used
-     * in this UI. Set once on UI creation and cannot be changed afterwards.
+     * in this UI.
      * 
      * @param pushMode
      *            The push mode to use.
@@ -1245,16 +1251,13 @@ public abstract class UI extends AbstractSingleComponentContainer implements
      * @throws IllegalArgumentException
      *             if the argument is null.
      * @throws IllegalStateException
-     *             if the mode is already set or if push support is not
-     *             available.
+     *             if push support is not available.
      */
     public void setPushMode(PushMode pushMode) {
         if (pushMode == null) {
             throw new IllegalArgumentException("Push mode cannot be null");
         }
-        if (this.pushMode != null) {
-            throw new IllegalStateException("Push mode already set");
-        }
+
         if (pushMode.isEnabled()) {
             VaadinSession session = getSession();
             if (session != null && !session.getService().ensurePushAvailable()) {
@@ -1262,7 +1265,13 @@ public abstract class UI extends AbstractSingleComponentContainer implements
                         "Push is not available. See previous log messages for more information.");
             }
         }
-        this.pushMode = pushMode;
+
+        /*
+         * Client-side will open a new connection or disconnect the old
+         * connection, so there's nothing more to do on the server at this
+         * point.
+         */
+        getState().pushMode = pushMode;
     }
 
 }