Fix DragAndDropWrapper update after file upload (#19616)

After a file has been uploaded VDragAndDropWrapper tries to pull changes
from the server by calling
ApplicationConnection.sendPendingVariableChanges() which has no effect.

This change replaces the
ApplicationConnection.sendPendingVariableChanges() call with an RPC.

Change-Id: Ibdf7f4d702add9507dbe54c1fdb402f0f4b19d19

2 files changed, 27 insertions, 4 deletions

diff --git a/client/src/com/vaadin/client/ui/VDragAndDropWrapper.java b/client/src/com/vaadin/client/ui/VDragAndDropWrapper.java
index f3905f9e46..a4cdd6e70f 100644
--- a/client/src/com/vaadin/client/ui/VDragAndDropWrapper.java
+++ b/client/src/com/vaadin/client/ui/VDragAndDropWrapper.java
@@ -196,6 +196,9 @@ public class VDragAndDropWrapper extends VCustomComponent implements
     /** For internal use only. May be removed or replaced in the future. */
     public VAbstractDropHandler dropHandler;
 
+    /** For internal use only. May be removed or replaced in the future. */
+    public UploadHandler uploadHandler;
+
     private VDragEvent vaadinDragEvent;
 
     int filecounter = 0;
@@ -239,9 +242,9 @@ public class VDragAndDropWrapper extends VCustomComponent implements
         @Override
         public void onReadyStateChange(XMLHttpRequest xhr) {
             if (xhr.getReadyState() == XMLHttpRequest.DONE) {
-                // visit server for possible
-                // variable changes
-                client.sendPendingVariableChanges();
+                // #19616 Notify the upload handler that the request is complete
+                // and let it poll the server for changes.
+                uploadHandler.uploadDone();
                 uploading = false;
                 startNextUpload();
                 xhr.clearOnReadyStateChange();
@@ -727,4 +730,10 @@ public class VDragAndDropWrapper extends VCustomComponent implements
         return dragImageWidget;
     }
 
+    public interface UploadHandler {
+
+        public void uploadDone();
+
+    }
+
 }
diff --git a/client/src/com/vaadin/client/ui/draganddropwrapper/DragAndDropWrapperConnector.java b/client/src/com/vaadin/client/ui/draganddropwrapper/DragAndDropWrapperConnector.java
index f222721e24..7ea9596809 100644
--- a/client/src/com/vaadin/client/ui/draganddropwrapper/DragAndDropWrapperConnector.java
+++ b/client/src/com/vaadin/client/ui/draganddropwrapper/DragAndDropWrapperConnector.java
@@ -30,11 +30,18 @@ import com.vaadin.client.ui.VDragAndDropWrapper;
 import com.vaadin.client.ui.customcomponent.CustomComponentConnector;
 import com.vaadin.shared.ui.Connect;
 import com.vaadin.shared.ui.draganddropwrapper.DragAndDropWrapperConstants;
+import com.vaadin.shared.ui.draganddropwrapper.DragAndDropWrapperServerRpc;
 import com.vaadin.ui.DragAndDropWrapper;
 
 @Connect(DragAndDropWrapper.class)
 public class DragAndDropWrapperConnector extends CustomComponentConnector
-        implements Paintable {
+        implements Paintable, VDragAndDropWrapper.UploadHandler {
+
+    @Override
+    protected void init() {
+        super.init();
+        getWidget().uploadHandler = this;
+    }
 
     @Override
     public void updateFromUIDL(UIDL uidl, ApplicationConnection client) {
@@ -121,4 +128,11 @@ public class DragAndDropWrapperConnector extends CustomComponentConnector
     private static Logger getLogger() {
         return Logger.getLogger(DragAndDropWrapperConnector.class.getName());
     }
+
+    @Override
+    public void uploadDone() {
+        // #19616 RPC to poll the server for changes
+        getRpcProxy(DragAndDropWrapperServerRpc.class).poll();
+    }
+
 }