Properly deserialize push connection (#12235)

The UI.pushConnection field is transient no longer; instead PushConnection
implementations must take care of serialization internally. When a session
is serialized, the client should notice that push was disconnected and
try to reconnect. A deserialized PushConnection should be in a "disconnected"
state so the eventual client reconnection works correctly.

Change-Id: I38cfc5a5cdbd3643311f830f8d580458dcd85c56

3 files changed, 28 insertions, 8 deletions

diff --git a/server/src/com/vaadin/server/communication/AtmospherePushConnection.java b/server/src/com/vaadin/server/communication/AtmospherePushConnection.java
index 3eae848adc..f8ef360eda 100644
--- a/server/src/com/vaadin/server/communication/AtmospherePushConnection.java
+++ b/server/src/com/vaadin/server/communication/AtmospherePushConnection.java
@@ -17,6 +17,7 @@
 package com.vaadin.server.communication;
 
 import java.io.IOException;
+import java.io.ObjectInputStream;
 import java.io.Reader;
 import java.io.Serializable;
 import java.io.StringReader;
@@ -117,11 +118,11 @@ public class AtmospherePushConnection implements PushConnection {
         CONNECTED;
     }
 
-    private State state = State.DISCONNECTED;
     private UI ui;
-    private AtmosphereResource resource;
-    private FragmentedMessage incomingMessage;
-    private Future<Object> outgoingMessage;
+    private transient State state = State.DISCONNECTED;
+    private transient AtmosphereResource resource;
+    private transient FragmentedMessage incomingMessage;
+    private transient Future<Object> outgoingMessage;
 
     public AtmospherePushConnection(UI ui) {
         this.ui = ui;
@@ -209,6 +210,7 @@ public class AtmospherePushConnection implements PushConnection {
 
     @Override
     public boolean isConnected() {
+        assert state != null;
         assert (state == State.CONNECTED) ^ (resource == null);
         return state == State.CONNECTED;
     }
@@ -297,8 +299,25 @@ public class AtmospherePushConnection implements PushConnection {
         state = State.DISCONNECTED;
     }
 
+    /**
+     * Returns the state of this connection.
+     */
+    protected State getState() {
+        return state;
+    }
+
+    /**
+     * Reinitializes this PushConnection after deserialization. The connection
+     * is initially in disconnected state; the client will handle the
+     * reconnecting.
+     */
+    private void readObject(ObjectInputStream stream) throws IOException,
+            ClassNotFoundException {
+        stream.defaultReadObject();
+        state = State.DISCONNECTED;
+    }
+
     private static Logger getLogger() {
         return Logger.getLogger(AtmospherePushConnection.class.getName());
     }
-
 }
diff --git a/server/src/com/vaadin/server/communication/PushConnection.java b/server/src/com/vaadin/server/communication/PushConnection.java
index 52efcfcd89..d5a0d6e9bc 100644
--- a/server/src/com/vaadin/server/communication/PushConnection.java
+++ b/server/src/com/vaadin/server/communication/PushConnection.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.server.communication;
 
+import java.io.Serializable;
+
 import com.vaadin.ui.UI;
 
 /**
@@ -30,7 +32,7 @@ import com.vaadin.ui.UI;
  * @author Vaadin Ltd
  * @since 7.1
  */
-public interface PushConnection {
+public interface PushConnection extends Serializable {
 
     /**
      * Pushes pending state changes and client RPC calls to the client. Can be
diff --git a/server/src/com/vaadin/ui/UI.java b/server/src/com/vaadin/ui/UI.java
index 7a71083e85..562b30f81d 100644
--- a/server/src/com/vaadin/ui/UI.java
+++ b/server/src/com/vaadin/ui/UI.java
@@ -553,7 +553,7 @@ public abstract class UI extends AbstractSingleComponentContainer implements
 
     private Navigator navigator;
 
-    private transient PushConnection pushConnection = null;
+    private PushConnection pushConnection = null;
 
     private LocaleService localeService = new LocaleService(this,
             getState(false).localeServiceState);
@@ -1626,5 +1626,4 @@ public abstract class UI extends AbstractSingleComponentContainer implements
     public String getEmbedId() {
         return embedId;
     }
-
 }