initial implementation of code splitting #4408

svn changeset:13561/svn branch:6.4

src/com/vaadin/terminal/gwt/client/ApplicationConfiguration.java

@@ -6,11 +6,12 @@ package com.vaadin.terminal.gwt.client;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 
-import com.google.gwt.core.client.GWT;
 import com.google.gwt.core.client.JavaScriptObject;
 import com.google.gwt.core.client.JsArrayString;
+import com.google.gwt.user.client.Command;
 import com.vaadin.terminal.gwt.client.ui.VUnknownComponent;
 
 public class ApplicationConfiguration {
@@ -37,6 +38,11 @@ public class ApplicationConfiguration {
 
     private String windowId;
 
+    // TODO consider to make this hashmap per application
+    LinkedList<Command> callbacks = new LinkedList<Command>();
+
+    private int widgetsLoading;
+
     private static ArrayList<ApplicationConnection> unstartedApplications = new ArrayList<ApplicationConnection>();
     private static ArrayList<ApplicationConnection> runningApplications = new ArrayList<ApplicationConnection>();
 
@@ -146,11 +152,6 @@ public class ApplicationConfiguration {
      *            the widgetset that is running the apps
      */
     public static void initConfigurations(WidgetSet widgetset) {
-        String wsname = widgetset.getClass().getName();
-        String module = GWT.getModuleName();
-        int lastdot = module.lastIndexOf(".");
-        String base = module.substring(0, lastdot);
-        String simpleName = module.substring(lastdot + 1);
 
         if (initedWidgetSet != null) {
             // Multiple widgetsets inited; can happen with custom WS + entry
@@ -241,7 +242,7 @@ public class ApplicationConfiguration {
         for (int i = 0; i < keyArray.length(); i++) {
             String key = keyArray.get(i).intern();
             int value = valueMap.getInt(key);
-            classes[value] = widgetSet.getImplementationByClassName(key);
+            classes[value] = widgetSet.getImplementationByClassName(key, this);
             if (classes[value] == VUnknownComponent.class) {
                 if (unknownComponents == null) {
                     unknownComponents = new HashMap<String, String>();
@@ -267,4 +268,31 @@ public class ApplicationConfiguration {
         }
         return null;
     }
+
+    /**
+     * 
+     * @param c
+     */
+    void runWhenWidgetsLoaded(Command c) {
+        if (widgetsLoading == 0) {
+            c.execute();
+        } else {
+            callbacks.add(c);
+        }
+    }
+
+    void widgetLoadStart() {
+        widgetsLoading++;
+    }
+
+    void widgetLoaded() {
+        widgetsLoading--;
+        if (widgetsLoading == 0 && !callbacks.isEmpty()) {
+            for (Command cmd : callbacks) {
+                cmd.execute();
+            }
+            callbacks.clear();
+        }
+
+    }
 }

src/com/vaadin/terminal/gwt/client/ApplicationConnection.java

@@ -670,10 +670,10 @@ public class ApplicationConnection {
 
     private void handleReceivedJSONMessage(Response response) {
         final Date start = new Date();
-        String jsonText = response.getText();
         // for(;;);[realjson]
-        jsonText = jsonText.substring(9, jsonText.length() - 1);
-        ValueMap json;
+        final String jsonText = response.getText().substring(9,
+                response.getText().length() - 1);
+        final ValueMap json;
         try {
             json = parseJSONResponse(jsonText);
         } catch (final Exception e) {
@@ -714,159 +714,181 @@ public class ApplicationConnection {
                     json.getValueMap("typeMappings"), widgetSet);
         }
 
-        if (json.containsKey("locales")) {
-            // Store locale data
-            JsArray<ValueMap> valueMapArray = json
-                    .getJSValueMapArray("locales");
-            LocaleService.addLocales(valueMapArray);
-        }
+        Command c = new Command() {
+            public void execute() {
 
-        ValueMap meta = null;
-        if (json.containsKey("meta")) {
-            meta = json.getValueMap("meta");
-            if (meta.containsKey("repaintAll")) {
-                view.clear();
-                idToPaintableDetail.clear();
-                if (meta.containsKey("invalidLayouts")) {
-                    validatingLayouts = true;
-                    zeroWidthComponents = new HashSet<Paintable>();
-                    zeroHeightComponents = new HashSet<Paintable>();
+                if (json.containsKey("locales")) {
+                    // Store locale data
+                    JsArray<ValueMap> valueMapArray = json
+                            .getJSValueMapArray("locales");
+                    LocaleService.addLocales(valueMapArray);
                 }
-            }
-            if (meta.containsKey("timedRedirect")) {
-                final ValueMap timedRedirect = meta
-                        .getValueMap("timedRedirect");
-                redirectTimer = new Timer() {
-                    @Override
-                    public void run() {
-                        redirect(timedRedirect.getString("url"));
+
+                ValueMap meta = null;
+                if (json.containsKey("meta")) {
+                    meta = json.getValueMap("meta");
+                    if (meta.containsKey("repaintAll")) {
+                        view.clear();
+                        idToPaintableDetail.clear();
+                        if (meta.containsKey("invalidLayouts")) {
+                            validatingLayouts = true;
+                            zeroWidthComponents = new HashSet<Paintable>();
+                            zeroHeightComponents = new HashSet<Paintable>();
+                        }
                     }
-                };
-                sessionExpirationInterval = timedRedirect.getInt("interval");
-            }
-        }
+                    if (meta.containsKey("timedRedirect")) {
+                        final ValueMap timedRedirect = meta
+                                .getValueMap("timedRedirect");
+                        redirectTimer = new Timer() {
+                            @Override
+                            public void run() {
+                                redirect(timedRedirect.getString("url"));
+                            }
+                        };
+                        sessionExpirationInterval = timedRedirect
+                                .getInt("interval");
+                    }
+                }
 
-        if (redirectTimer != null) {
-            redirectTimer.schedule(1000 * sessionExpirationInterval);
-        }
+                if (redirectTimer != null) {
+                    redirectTimer.schedule(1000 * sessionExpirationInterval);
+                }
 
-        // Process changes
-        JsArray<ValueMap> changes = json.getJSValueMapArray("changes");
+                // Process changes
+                JsArray<ValueMap> changes = json.getJSValueMapArray("changes");
 
-        ArrayList<Paintable> updatedWidgets = new ArrayList<Paintable>();
-        relativeSizeChanges.clear();
-        componentCaptionSizeChanges.clear();
+                ArrayList<Paintable> updatedWidgets = new ArrayList<Paintable>();
+                relativeSizeChanges.clear();
+                componentCaptionSizeChanges.clear();
 
-        int length = changes.length();
-        for (int i = 0; i < length; i++) {
-            try {
-                final UIDL change = changes.get(i).cast();
-                try {
-                    console.dirUIDL(change);
-                } catch (final Exception e) {
-                    ClientExceptionHandler.displayError(e);
-                    // TODO: dir doesn't work in any browser although it should
-                    // work (works in hosted mode)
-                    // it partially did at some part but now broken.
-                }
-                final UIDL uidl = change.getChildUIDL(0);
-                // TODO optimize
-                final Paintable paintable = getPaintable(uidl.getId());
-                if (paintable != null) {
-                    paintable.updateFromUIDL(uidl, this);
-                    // paintable may have changed during render to another
-                    // implementation, use the new one for updated widgets map
-                    updatedWidgets.add(idToPaintableDetail.get(uidl.getId())
-                            .getComponent());
-                } else {
-                    if (!uidl.getTag().equals(
-                            configuration.getEncodedWindowTag())) {
-                        ClientExceptionHandler
-                                .displayError("Received update for "
-                                        + uidl.getTag()
-                                        + ", but there is no such paintable ("
-                                        + uidl.getId() + ") rendered.");
-                    } else {
-                        view.updateFromUIDL(uidl, this);
+                int length = changes.length();
+                for (int i = 0; i < length; i++) {
+                    try {
+                        final UIDL change = changes.get(i).cast();
+                        try {
+                            console.dirUIDL(change);
+                        } catch (final Exception e) {
+                            ClientExceptionHandler.displayError(e);
+                            // TODO: dir doesn't work in any browser although it
+                            // should
+                            // work (works in hosted mode)
+                            // it partially did at some part but now broken.
+                        }
+                        final UIDL uidl = change.getChildUIDL(0);
+                        // TODO optimize
+                        final Paintable paintable = getPaintable(uidl.getId());
+                        if (paintable != null) {
+                            paintable.updateFromUIDL(uidl,
+                                    ApplicationConnection.this);
+                            // paintable may have changed during render to
+                            // another
+                            // implementation, use the new one for updated
+                            // widgets map
+                            updatedWidgets.add(idToPaintableDetail.get(
+                                    uidl.getId()).getComponent());
+                        } else {
+                            if (!uidl.getTag().equals(
+                                    configuration.getEncodedWindowTag())) {
+                                ClientExceptionHandler
+                                        .displayError("Received update for "
+                                                + uidl.getTag()
+                                                + ", but there is no such paintable ("
+                                                + uidl.getId() + ") rendered.");
+                            } else {
+                                view.updateFromUIDL(uidl,
+                                        ApplicationConnection.this);
+                            }
+                        }
+                    } catch (final Throwable e) {
+                        ClientExceptionHandler.displayError(e);
                     }
                 }
-            } catch (final Throwable e) {
-                ClientExceptionHandler.displayError(e);
-            }
-        }
 
-        if (json.containsKey("dd")) {
-            // response contains data for drag and drop service
-            VDragAndDropManager.get().handleServerResponse(
-                    json.getValueMap("dd"));
-        }
+                if (json.containsKey("dd")) {
+                    // response contains data for drag and drop service
+                    VDragAndDropManager.get().handleServerResponse(
+                            json.getValueMap("dd"));
+                }
 
-        // Check which widgets' size has been updated
-        Set<Paintable> sizeUpdatedWidgets = new HashSet<Paintable>();
+                // Check which widgets' size has been updated
+                Set<Paintable> sizeUpdatedWidgets = new HashSet<Paintable>();
 
-        updatedWidgets.addAll(relativeSizeChanges);
-        sizeUpdatedWidgets.addAll(componentCaptionSizeChanges);
+                updatedWidgets.addAll(relativeSizeChanges);
+                sizeUpdatedWidgets.addAll(componentCaptionSizeChanges);
 
-        for (Paintable paintable : updatedWidgets) {
-            ComponentDetail detail = idToPaintableDetail.get(getPid(paintable));
-            Widget widget = (Widget) paintable;
-            Size oldSize = detail.getOffsetSize();
-            Size newSize = new Size(widget.getOffsetWidth(), widget
-                    .getOffsetHeight());
+                for (Paintable paintable : updatedWidgets) {
+                    ComponentDetail detail = idToPaintableDetail
+                            .get(getPid(paintable));
+                    Widget widget = (Widget) paintable;
+                    Size oldSize = detail.getOffsetSize();
+                    Size newSize = new Size(widget.getOffsetWidth(), widget
+                            .getOffsetHeight());
 
-            if (oldSize == null || !oldSize.equals(newSize)) {
-                sizeUpdatedWidgets.add(paintable);
-                detail.setOffsetSize(newSize);
-            }
+                    if (oldSize == null || !oldSize.equals(newSize)) {
+                        sizeUpdatedWidgets.add(paintable);
+                        detail.setOffsetSize(newSize);
+                    }
 
-        }
+                }
 
-        Util.componentSizeUpdated(sizeUpdatedWidgets);
+                Util.componentSizeUpdated(sizeUpdatedWidgets);
 
-        if (meta != null) {
-            if (meta.containsKey("appError")) {
-                ValueMap error = meta.getValueMap("appError");
-                String html = "";
-                if (error.containsKey("caption")
-                        && error.getString("caption") != null) {
-                    html += "<h1>" + error.getAsString("caption") + "</h1>";
-                }
-                if (error.containsKey("message")
-                        && error.getString("message") != null) {
-                    html += "<p>" + error.getAsString("message") + "</p>";
-                }
-                String url = null;
-                if (error.containsKey("url")) {
-                    url = error.getString("url");
-                }
+                if (meta != null) {
+                    if (meta.containsKey("appError")) {
+                        ValueMap error = meta.getValueMap("appError");
+                        String html = "";
+                        if (error.containsKey("caption")
+                                && error.getString("caption") != null) {
+                            html += "<h1>" + error.getAsString("caption")
+                                    + "</h1>";
+                        }
+                        if (error.containsKey("message")
+                                && error.getString("message") != null) {
+                            html += "<p>" + error.getAsString("message")
+                                    + "</p>";
+                        }
+                        String url = null;
+                        if (error.containsKey("url")) {
+                            url = error.getString("url");
+                        }
 
-                if (html.length() != 0) {
-                    /* 45 min */
-                    VNotification n = new VNotification(1000 * 60 * 45);
-                    n.addEventListener(new NotificationRedirect(url));
-                    n.show(html, VNotification.CENTERED_TOP,
-                            VNotification.STYLE_SYSTEM);
-                } else {
-                    redirect(url);
+                        if (html.length() != 0) {
+                            /* 45 min */
+                            VNotification n = new VNotification(1000 * 60 * 45);
+                            n.addEventListener(new NotificationRedirect(url));
+                            n.show(html, VNotification.CENTERED_TOP,
+                                    VNotification.STYLE_SYSTEM);
+                        } else {
+                            redirect(url);
+                        }
+                        applicationRunning = false;
+                    }
+                    if (validatingLayouts) {
+                        getConsole().printLayoutProblems(meta,
+                                ApplicationConnection.this,
+                                zeroHeightComponents, zeroWidthComponents);
+                        zeroHeightComponents = null;
+                        zeroWidthComponents = null;
+                        validatingLayouts = false;
+
+                    }
                 }
-                applicationRunning = false;
-            }
-            if (validatingLayouts) {
-                getConsole().printLayoutProblems(meta, this,
-                        zeroHeightComponents, zeroWidthComponents);
-                zeroHeightComponents = null;
-                zeroWidthComponents = null;
-                validatingLayouts = false;
 
-            }
-        }
+                // TODO build profiling for widget impl loading time
+
+                final long prosessingTime = (new Date().getTime())
+                        - start.getTime();
+                console.log(" Processing time was "
+                        + String.valueOf(prosessingTime) + "ms for "
+                        + jsonText.length() + " characters of JSON");
+                console.log("Referenced paintables: "
+                        + idToPaintableDetail.size());
 
-        final long prosessingTime = (new Date().getTime()) - start.getTime();
-        console.log(" Processing time was " + String.valueOf(prosessingTime)
-                + "ms for " + jsonText.length() + " characters of JSON");
-        console.log("Referenced paintables: " + idToPaintableDetail.size());
+                endRequest();
 
-        endRequest();
+            }
+        };
+        configuration.runWhenWidgetsLoaded(c);
     }
 
     /**

src/com/vaadin/terminal/gwt/client/DefaultWidgetSet.java

@@ -9,7 +9,6 @@ import com.google.gwt.user.client.ui.Widget;
 import com.vaadin.terminal.gwt.client.ui.VButton;
 import com.vaadin.terminal.gwt.client.ui.VCheckBox;
 import com.vaadin.terminal.gwt.client.ui.VDateFieldCalendar;
-import com.vaadin.terminal.gwt.client.ui.VDragAndDropWrapper;
 import com.vaadin.terminal.gwt.client.ui.VFilterSelect;
 import com.vaadin.terminal.gwt.client.ui.VListSelect;
 import com.vaadin.terminal.gwt.client.ui.VNativeSelect;
@@ -69,7 +68,7 @@ public class DefaultWidgetSet implements WidgetSet {
         Class<? extends Paintable> widgetClass = conf
                 .getWidgetClassByEncodedTag(tag);
 
-        // TODO add our quirks
+        // add our historical quirks
 
         if (widgetClass == VButton.class && uidl.hasAttribute("type")) {
             return VCheckBox.class;
@@ -119,10 +118,13 @@ public class DefaultWidgetSet implements WidgetSet {
     }
 
     public Class<? extends Paintable> getImplementationByClassName(
-            String fullyqualifiedName) {
+            String fullyqualifiedName,
+            ApplicationConfiguration applicationConfiguration) {
         Class<? extends Paintable> implementationByServerSideClassName = map
-                .getImplementationByServerSideClassName(fullyqualifiedName);
+                .getImplementationByServerSideClassName(fullyqualifiedName,
+                        applicationConfiguration);
         return implementationByServerSideClassName;
 
     }
+
 }

src/com/vaadin/terminal/gwt/client/WidgetMap.java

@@ -12,6 +12,7 @@ import com.vaadin.terminal.gwt.client.ui.VWindow;
 public abstract class WidgetMap {
 
     public Paintable instantiate(Class<? extends Paintable> classType) {
+
         /*
          * Yes, this (including the generated) may look very odd code, but due
          * the nature of GWT, we cannot do this with reflect. Luckily this is
@@ -36,6 +37,7 @@ public abstract class WidgetMap {
     }
 
     public abstract Class<? extends Paintable> getImplementationByServerSideClassName(
-            String fullyqualifiedName);
+            String fullyqualifiedName,
+            ApplicationConfiguration applicationConfiguration);
 
 }

src/com/vaadin/terminal/gwt/client/WidgetSet.java

@@ -42,9 +42,11 @@ public interface WidgetSet extends EntryPoint {
      * qualified name.
      * 
      * @param fullyQualifiedName
+     * @param applicationConfiguration
      * @return
      */
     public Class<? extends Paintable> getImplementationByClassName(
-            String fullyQualifiedName);
+            String fullyQualifiedName,
+            ApplicationConfiguration applicationConfiguration);
 
 }

src/com/vaadin/terminal/gwt/widgetsetutils/WidgetMapGenerator.java

@@ -78,6 +78,8 @@ public class WidgetMapGenerator extends Generator {
         ClassSourceFileComposerFactory composer = null;
         composer = new ClassSourceFileComposerFactory(packageName, className);
         composer.addImport("com.google.gwt.core.client.GWT");
+        composer.addImport("java.util.HashMap");
+        composer.addImport("com.google.gwt.core.client.RunAsyncCallback");
         composer.setSuperclass("com.vaadin.terminal.gwt.client.WidgetMap");
         SourceWriter sourceWriter = composer.createSourceWriter(context,
                 printWriter);
@@ -145,12 +147,10 @@ public class WidgetMapGenerator extends Generator {
     }
 
     /**
-     * This method is protected to allow easy creation of optimized widgetsets.
-     * <p>
-     * TODO we need some sort of mechanism to easily exclude/include components
-     * from widgetset. Properties in gwt.xml is one option. Now only possible by
-     * extending this class, overriding getUsedPaintables() method and
-     * redefining deferred binding rule.
+     * This method is protected to allow creation of optimized widgetsets. The
+     * Widgetset will contain only implementation returned by this function. If
+     * one knows which widgets are needed for the application, returning only
+     * them here will significantly optimize the size of the produced JS.
      * 
      * @return a collections of Vaadin components that will be added to
      *         widgetset
@@ -159,16 +159,42 @@ public class WidgetMapGenerator extends Generator {
         return ClassPathExplorer.getPaintablesHavingWidgetAnnotation();
     }
 
+    /**
+     * Returns true if the widget for given component will be lazy loaded by the
+     * client. The default implementation reads the information from the
+     * {@link ClientWidget} annotation.
+     * <p>
+     * The method can be overridden to optimize the widget loading mechanism. If
+     * the Widgetset is wanted to be optimized for a network with a high latency
+     * or for a one with a very fast throughput, it may be good to return false
+     * for every component.
+     * 
+     * @param paintableType
+     * @return true iff the widget for given component should be lazy loaded by
+     *         the client side engine
+     */
+    protected boolean isLazyLoaded(Class<? extends Paintable> paintableType) {
+        ClientWidget annotation = paintableType
+                .getAnnotation(ClientWidget.class);
+        return annotation.lazyLoad();
+    }
+
     private void generateInstantiatorMethod(
             SourceWriter sourceWriter,
             Collection<Class<? extends Paintable>> paintablesHavingWidgetAnnotation) {
+
         sourceWriter
-                .println("public Paintable instantiate(Class<? extends Paintable> classType) {");
-        sourceWriter.indent();
+                .println("public interface Instantiator { public Paintable get();};");
+
+        // TODO detect if it would be noticably faster to instantiate with a
+        // lookup with index than with the hashmap
 
         sourceWriter
-                .println("Paintable p = super.instantiate(classType); if(p!= null) return p;");
+                .println("private HashMap<Class,Instantiator> instmap = new HashMap<Class,Instantiator>();");
 
+        sourceWriter
+                .println("public void ensureInstantiator(Class<? extends Paintable> classType, final ApplicationConfiguration c) {");
+        sourceWriter.println("if(!instmap.containsKey(classType)){");
         for (Class<? extends Paintable> class1 : paintablesHavingWidgetAnnotation) {
             ClientWidget annotation = class1.getAnnotation(ClientWidget.class);
             Class<? extends com.vaadin.terminal.gwt.client.Paintable> clientClass = annotation
@@ -177,14 +203,50 @@ public class WidgetMapGenerator extends Generator {
                 // VView's are not instantiated by widgetset
                 continue;
             }
-            sourceWriter.print("if (");
-            sourceWriter.print(clientClass.getName());
-            sourceWriter.print(".class == classType) return GWT.create(");
-            sourceWriter.print(clientClass.getName());
-            sourceWriter.println(".class );");
-            sourceWriter.print("else ");
+            sourceWriter.print("if( classType == " + clientClass.getName()
+                    + ".class) {");
+
+            String instantiator = "new Instantiator() { public Paintable get(){ return GWT.create("
+                    + clientClass.getName() + ".class );}}";
+
+            if (isLazyLoaded(class1)) {
+                sourceWriter
+                        .print("c.widgetLoadStart();GWT.runAsync(new RunAsyncCallback() {\n"
+                                + "            public void onSuccess() {");
+
+                sourceWriter.print("instmap.put(");
+                sourceWriter.print(clientClass.getName());
+                sourceWriter.print(".class, ");
+                sourceWriter.print(instantiator);
+                sourceWriter.println("); c.widgetLoaded();");
+                sourceWriter
+                        .print("            }\n"
+                                + "\n"
+                                + "            public void onFailure(Throwable reason) {c.widgetLoaded();\n"
+                                + "\n" + "            }\n" + "        });\n");
+
+            } else {
+                // widget implementation in initially loaded js script
+                sourceWriter.print("instmap.put(");
+                sourceWriter.print(clientClass.getName());
+                sourceWriter.print(".class, ");
+                sourceWriter.print(instantiator);
+                sourceWriter.print(");");
+            }
+            sourceWriter.print("}");
         }
-        sourceWriter.println("return null;");
+
+        sourceWriter.println("}");
+
+        sourceWriter.println("}");
+
+        sourceWriter
+                .println("public Paintable instantiate(Class<? extends Paintable> classType) {");
+        sourceWriter.indent();
+        sourceWriter
+                .println("Paintable p = super.instantiate(classType); if(p!= null) return p;");
+        sourceWriter.println("return instmap.get(classType).get();");
+
         sourceWriter.outdent();
         sourceWriter.println("}");
     }
@@ -200,7 +262,7 @@ public class WidgetMapGenerator extends Generator {
             Collection<Class<? extends Paintable>> paintablesHavingWidgetAnnotation) {
         sourceWriter
                 .println("public Class<? extends Paintable> "
-                        + "getImplementationByServerSideClassName(String fullyQualifiedName) {");
+                        + "getImplementationByServerSideClassName(String fullyQualifiedName, ApplicationConfiguration c) {");
         sourceWriter.indent();
         sourceWriter
                 .println("fullyQualifiedName = fullyQualifiedName.intern();");
@@ -211,9 +273,10 @@ public class WidgetMapGenerator extends Generator {
                     .value();
             sourceWriter.print("if ( fullyQualifiedName == \"");
             sourceWriter.print(class1.getName());
-            sourceWriter.print("\" ) return ");
+            sourceWriter.print("\" ) { ensureInstantiator("
+                    + clientClass.getName() + ".class, c); return ");
             sourceWriter.print(clientClass.getName());
-            sourceWriter.println(".class;");
+            sourceWriter.println(".class;}");
             sourceWriter.print("else ");
         }
         sourceWriter
@@ -222,5 +285,4 @@ public class WidgetMapGenerator extends Generator {
         sourceWriter.println("}");
 
     }
-
 }

src/com/vaadin/ui/Button.java

@@ -33,7 +33,7 @@ import com.vaadin.ui.themes.BaseTheme;
  * @since 3.0
  */
 @SuppressWarnings("serial")
-@ClientWidget(VButton.class)
+@ClientWidget(value = VButton.class, lazyLoad = false)
 public class Button extends AbstractField implements FieldEvents.BlurNotifier,
         FieldEvents.FocusNotifier {
 
@@ -472,7 +472,7 @@ public class Button extends AbstractField implements FieldEvents.BlurNotifier,
 
         @Override
         public void handleAction(Object sender, Object target) {
-            this.button.fireClick();
+            button.fireClick();
         }
     }
 

src/com/vaadin/ui/ClientWidget.java

@@ -12,6 +12,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import com.vaadin.terminal.gwt.client.Paintable;
+import com.vaadin.terminal.gwt.widgetsetutils.WidgetMapGenerator;
 
 /**
  * Annotation defining the default client side counterpart in GWT terminal for
@@ -35,4 +36,34 @@ public @interface ClientWidget {
      * @return the client side counterpart for the annotated component
      */
     Class<? extends Paintable> value();
+
+    /**
+     * The lazy loading of a widget implementation means the client side
+     * component is not included in the initial JavaScript application loaded
+     * when the application starts. Instead the implementation is loaded to the
+     * client when it is first needed.
+     * <p>
+     * Lazy loaded widgets don't stress the size and startup time of the client
+     * side as much as eagerly loaded widgets. On the other hand there is a
+     * slight latency when lazy loaded widgets are first used as the client side
+     * needs to visit the server to fetch the client side implementation.
+     * <p>
+     * In common situations the default value should be fine. If the widget
+     * implementation commonly used and often on first view it is better set
+     * lazy loading off for it. Also if the component implementation is really
+     * thing, it may by justified to make the widget implementation eagerly
+     * loaded.
+     * <p>
+     * Tunings to widget loading can also be made by overriding
+     * {@link WidgetMapGenerator} in GWT module. Tunings might be helpful if the
+     * end users have slow connections and especially if they have high latency
+     * in their network.
+     * 
+     * @return if true (default), the GWT code generator will make the client
+     *         side implementation lazy loaded. Displaying it first time on the
+     *         screen slightly increases, but widgets implementation does not
+     *         stress the initialization of the client side engine.
+     */
+    boolean lazyLoad() default true;
+
 }

src/com/vaadin/ui/CustomComponent.java

@@ -26,7 +26,7 @@ import com.vaadin.terminal.gwt.client.ui.VCustomComponent;
  * @since 3.0
  */
 @SuppressWarnings("serial")
-@ClientWidget(VCustomComponent.class)
+@ClientWidget(value = VCustomComponent.class, lazyLoad = false)
 public class CustomComponent extends AbstractComponentContainer {
 
     /**

src/com/vaadin/ui/HorizontalLayout.java

@@ -17,7 +17,7 @@ import com.vaadin.terminal.gwt.client.ui.VHorizontalLayout;
  * @since 5.3
  */
 @SuppressWarnings("serial")
-@ClientWidget(VHorizontalLayout.class)
+@ClientWidget(value = VHorizontalLayout.class, lazyLoad = false)
 public class HorizontalLayout extends AbstractOrderedLayout {
 
     public HorizontalLayout() {

src/com/vaadin/ui/Label.java

@@ -38,7 +38,7 @@ import com.vaadin.terminal.gwt.client.ui.VLabel;
  * @since 3.0
  */
 @SuppressWarnings("serial")
-@ClientWidget(VLabel.class)
+@ClientWidget(value = VLabel.class, lazyLoad = false)
 public class Label extends AbstractComponent implements Property,
         Property.Viewer, Property.ValueChangeListener,
         Property.ValueChangeNotifier, Comparable {

src/com/vaadin/ui/OrderedLayout.java

@@ -24,7 +24,7 @@ import com.vaadin.terminal.gwt.client.ui.VOrderedLayout;
  */
 @SuppressWarnings("serial")
 @Deprecated
-@ClientWidget(VOrderedLayout.class)
+@ClientWidget(value = VOrderedLayout.class, lazyLoad = false)
 public class OrderedLayout extends AbstractOrderedLayout {
     /* Predefined orientations */
 

src/com/vaadin/ui/SplitPanel.java

@@ -30,7 +30,7 @@ import com.vaadin.tools.ReflectTools;
  * @since 5.0
  */
 @SuppressWarnings("serial")
-@ClientWidget(VSplitPanelHorizontal.class)
+@ClientWidget(value = VSplitPanelHorizontal.class, lazyLoad = false)
 public class SplitPanel extends AbstractLayout {
 
     /* Predefined orientations */

src/com/vaadin/ui/TextField.java

@@ -38,7 +38,7 @@ import com.vaadin.terminal.gwt.client.ui.VTextField;
  * @since 3.0
  */
 @SuppressWarnings("serial")
-@ClientWidget(VTextField.class)
+@ClientWidget(value = VTextField.class, lazyLoad = false)
 public class TextField extends AbstractField implements
         FieldEvents.BlurNotifier, FieldEvents.FocusNotifier {
 

src/com/vaadin/ui/UriFragmentUtility.java

@@ -20,7 +20,7 @@ import com.vaadin.terminal.gwt.client.ui.VUriFragmentUtility;
  * 
  */
 @SuppressWarnings("serial")
-@ClientWidget(VUriFragmentUtility.class)
+@ClientWidget(value = VUriFragmentUtility.class, lazyLoad = false)
 public class UriFragmentUtility extends AbstractComponent {
 
     /**

src/com/vaadin/ui/VerticalLayout.java

@@ -18,7 +18,7 @@ import com.vaadin.terminal.gwt.client.ui.VVerticalLayout;
  * @since 5.3
  */
 @SuppressWarnings("serial")
-@ClientWidget(VVerticalLayout.class)
+@ClientWidget(value = VVerticalLayout.class, lazyLoad = false)
 public class VerticalLayout extends AbstractOrderedLayout {
 
     public VerticalLayout() {