Make GeneratedPropertyItem addItem return null when appropriate (#18685)

Change-Id: I08f05bee9bf0c82f5767c63654046285c85f233a

1 files changed, 9 insertions, 0 deletions

diff --git a/server/src/com/vaadin/data/util/GeneratedPropertyContainer.java b/server/src/com/vaadin/data/util/GeneratedPropertyContainer.java
index cea1e27ee9..e0b2bb7c19 100644
--- a/server/src/com/vaadin/data/util/GeneratedPropertyContainer.java
+++ b/server/src/com/vaadin/data/util/GeneratedPropertyContainer.java
@@ -564,12 +564,18 @@ public class GeneratedPropertyContainer extends AbstractContainer implements
     public Item addItemAfter(Object previousItemId, Object newItemId)
             throws UnsupportedOperationException {
         Item item = wrappedContainer.addItemAfter(previousItemId, newItemId);
+        if (item == null) {
+            return null;
+        }
         return createGeneratedPropertyItem(newItemId, item);
     }
 
     @Override
     public Item addItem(Object itemId) throws UnsupportedOperationException {
         Item item = wrappedContainer.addItem(itemId);
+        if (item == null) {
+            return null;
+        }
         return createGeneratedPropertyItem(itemId, item);
     }
 
@@ -577,6 +583,9 @@ public class GeneratedPropertyContainer extends AbstractContainer implements
     public Item addItemAt(int index, Object newItemId)
             throws UnsupportedOperationException {
         Item item = wrappedContainer.addItemAt(index, newItemId);
+        if (item == null) {
+            return null;
+        }
         return createGeneratedPropertyItem(newItemId, item);
     }