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diff --git a/java/com/google/gwtexpui/user/client/View.java b/java/com/google/gwtexpui/user/client/View.java
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+++ b/java/com/google/gwtexpui/user/client/View.java
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+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gwtexpui.user.client;
+
+import com.google.gwt.user.client.ui.Composite;
+import com.google.gwt.user.client.ui.Widget;
+
+/**
+ * Widget to display within a {@link ViewSite}.
+ *
+ * <p>Implementations must override {@code protected void onLoad()} and arrange for {@link
+ * #display()} to be invoked once the DOM within the view is consistent for presentation to the
+ * user. Typically this means that the subclass can start RPCs within {@code onLoad()} and then
+ * invoke {@code display()} from within the AsyncCallback's {@code onSuccess(Object)} method.
+ */
+public abstract class View extends Composite {
+  ViewSite<? extends View> site;
+
+  @Override
+  protected void onUnload() {
+    site = null;
+    super.onUnload();
+  }
+
+  /** true if this is the current view of its parent view site */
+  public final boolean isCurrentView() {
+    Widget p = getParent();
+    while (p != null) {
+      if (p instanceof ViewSite<?>) {
+        return ((ViewSite<?>) p).getView() == this;
+      }
+      p = p.getParent();
+    }
+    return false;
+  }
+
+  /** Replace the current view in the parent ViewSite with this view. */
+  public final void display() {
+    if (site != null) {
+      site.swap(this);
+    }
+  }
+}