Add UI id to UICreateEvent for use in createInstance (#9721)

2 files changed, 37 insertions, 3 deletions

diff --git a/server/src/com/vaadin/server/AbstractCommunicationManager.java b/server/src/com/vaadin/server/AbstractCommunicationManager.java
index ed3b73dc20..b5237438ba 100644
--- a/server/src/com/vaadin/server/AbstractCommunicationManager.java
+++ b/server/src/com/vaadin/server/AbstractCommunicationManager.java
@@ -2525,9 +2525,11 @@ public abstract class AbstractCommunicationManager implements Serializable {
 
         // No existing UI found - go on by creating and initializing one
 
+        Integer uiId = Integer.valueOf(session.getNextUIid());
+
         // Explicit Class.cast to detect if the UIProvider does something
         // unexpected
-        UICreateEvent event = new UICreateEvent(request, uiClass);
+        UICreateEvent event = new UICreateEvent(request, uiClass, uiId);
         UI ui = uiClass.cast(provider.createInstance(event));
 
         // Initialize some fields for a newly created UI
@@ -2535,7 +2537,6 @@ public abstract class AbstractCommunicationManager implements Serializable {
             // Session already set for LegacyWindow
             ui.setSession(session);
         }
-        Integer uiId = Integer.valueOf(session.getNextUIid());
 
         // Set thread local here so it is available in init
         UI.setCurrent(ui);
diff --git a/server/src/com/vaadin/server/UICreateEvent.java b/server/src/com/vaadin/server/UICreateEvent.java
index 561bc4cdfa..a608b5eb19 100644
--- a/server/src/com/vaadin/server/UICreateEvent.java
+++ b/server/src/com/vaadin/server/UICreateEvent.java
@@ -28,9 +28,11 @@ import com.vaadin.ui.UI;
 public class UICreateEvent extends UIProviderEvent {
 
     private final Class<? extends UI> uiClass;
+    private final Integer uiId;
 
     /**
-     * Creates a new UI create event for a given VaadinRequest and UI class.
+     * Creates a new UI create event for a given VaadinRequest and UI class but
+     * without a UI id.
      * 
      * @param request
      *            the request for which the UI will be created
@@ -38,8 +40,26 @@ public class UICreateEvent extends UIProviderEvent {
      *            the UI class that will be created
      */
     public UICreateEvent(VaadinRequest request, Class<? extends UI> uiClass) {
+        this(request, uiClass, null);
+    }
+
+    /**
+     * Creates a new UI create event for a given VaadinRequest, UI class and UI
+     * id
+     * 
+     * @param request
+     *            the request for which the UI will be created
+     * @param uiClass
+     *            the UI class that will be created
+     * @param uiId
+     *            the id reserved for the UI; or <code>null</code> if no id has
+     *            yet been allocated.
+     */
+    public UICreateEvent(VaadinRequest request, Class<? extends UI> uiClass,
+            Integer uiId) {
         super(request);
         this.uiClass = uiClass;
+        this.uiId = uiId;
     }
 
     /**
@@ -51,4 +71,17 @@ public class UICreateEvent extends UIProviderEvent {
         return uiClass;
     }
 
+    /**
+     * Gets the id of the UI about to be created. This might be
+     * <code>null</code> if the id has not yet been determined.
+     * <p>
+     * The UI id is generally only available in
+     * {@link UIProvider#createInstance(UICreateEvent)}
+     * 
+     * @return the UI id; or <code>null</code> if the UI id is not yet known.
+     */
+    public Integer getUiId() {
+        return uiId;
+    }
+
 }