GWT Designer custom bean design restrictions

[peterblazejewicz]

Hi all,
that's probably question to Designer dev-team:
What are exact java bean desing requirements that should be followed by custom widget/composite built for use with GWT Designer upon existing GWT widgets or 3rd party widgets?
Especially I want to know if there are special non-javadoc/javadoc comments/annotations that could be applied to 3rd party components or my own ones to enable them succesfully being rendered in "Design" mode,
Also I'm wondering if dev-team could provide more specific GWT Designer annotation to instruct which constructor is to be used in Design mode (e.g. @gwtDesigner.constructor or anything similiar),
I'm aware that there was a topic on GWT toolkit JIRA about better GWT/3rd party ide's integration about that matter,

thanks,
regards,
Peter

[Eric Clayberg]

What are exact java bean desing requirements that should be followed by custom widget/composite built for use with GWT Designer upon existing GWT widgets or 3rd party widgets?

The basic rules are the same as those defined by the JavaBean spec and are discussed in this FAQ entry.

For GWT, any public Widget subclass that has a public, zero-argument constructor can be used (as is standard for all base GWT widgets). Custom properties are derived through reflection by looking for getter/setter pairs of known types. Custom Composite subclasses will show their subcomponents when placed in Designer.

Especially I want to know if there are special non-javadoc/javadoc comments/annotations that could be applied to 3rd party components or my own ones to enable them succesfully being rendered in "Design" mode

At the moment, no.

Also I'm wondering if dev-team could provide more specific GWT Designer annotation to instruct which constructor is to be used in Design mode (e.g. @gwtDesigner.constructor or anything similiar)

What would that annotation do in design mode?

I'm aware that there was a topic on GWT toolkit JIRA about better GWT/3rd party ide's integration about that matter

I think this is an area that Google needs to step into an assert some leadership...either by formally adopting the JavaBean spec (which they mostly do for their own widgets), or establishing some other convention (annotations or otherwise). We would certainly support anything that is officially made part of the GWT API.

[peterblazejewicz]

Hello Eric,

thanks for answer and confirming my thoughs about design requirements,

I think this is an area that Google needs to step into an assert some leadership...either by formally adopting the JavaBean spec (which they mostly do for their own widgets), or establishing some other convention (annotations or otherwise). We would certainly support anything that is officially made part of the GWT API.

they have just opened incubator area (like e.g. SwingX project):
http://code.google.com/p/google-web-toolkit-incubator/
small startup, maybe yuo could participate in gathering widget stuff requirements?

regards,
Peter

[Eric Clayberg]

maybe yuo could participate in gathering widget stuff requirements?

We'll talk to our contacts at Google about that.

[ekuleshov]

Eric, I took the last build of MyGWT which seem to have all default constructors and bean properties, so I've added MyGWT to the module config:

<module>
<inherits name="net.mygwt.ui.MyGWT" />
<inherits name="com.google.gwt.user.User"/>
<entry-point class="com.mycompany.project.client.ConfigExt"/>
</module>

And then tried to net.mygwt.ui.client.widget.Button widget to the root panel and for the following error, which seem like caused by NoClassDefFoundError upon Button class initialization (see below). Even visual editor shows that error I can run the app with GWT shell and can see MyGWT button in the shell. Do you have any clue what could be wrong?

Thanks
Eugene

Designer internal error [6.5.1.20080121131339]: Designer is unable to create the 'button' component at line 15 of ConfigExt.java, using public net.mygwt.ui.client.widget.Button() and arguments {}.
This can be caused by problems evaluating the arguments of the constructor, or by any other problem that triggers an exception in the component when instantiated.
See your Eclipse <workspace>.metadata\.log file for details.
Could not initialize class net.mygwt.ui.client.widget.Button

com.swtdesigner.properties.PropertyException: Designer is unable to create the 'button' component at line 15 of ConfigExt.java, using public net.mygwt.ui.client.widget.Button() and arguments {}.
This can be caused by problems evaluating the arguments of the constructor, or by any other problem that triggers an exception in the component when instantiated.
See your Eclipse <workspace>.metadata\.log file for details.
Could not initialize class net.mygwt.ui.client.widget.Button
at com.swtdesigner.model.swt.widgets.ConstructorSourcePropertiesHelper.createObject(ConstructorSourcePropertiesHelper.java:274)
at com.swtdesigner.gwt.model.widgets.UIObjectInfo.createWidgetInstance(UIObjectInfo.java:312)
at com.swtdesigner.gwt.model.widgets.UIObjectInfo.createWidget(UIObjectInfo.java:264)
at com.swtdesigner.gwt.model.widgets.WidgetInfo.createWidget(WidgetInfo.java:169)
at com.swtdesigner.gwt.model.widgets.panel.AbstractContainerInfo.createChildrenWidgets(AbstractContainerInfo.java:195)
at com.swtdesigner.gwt.model.widgets.panel.RootPanelInfo.createGUIComponent(RootPanelInfo.java:69)
at com.swtdesigner.model.JavaInfo$18.execute(JavaInfo.java:5608)
at com.swtdesigner.model.swing.properties.custom.DesignTimeHelper.execute(DesignTimeHelper.java:54)
at com.swtdesigner.model.JavaInfo.notifyPropertyChanged(JavaInfo.java:5603)
at com.swtdesigner.model.JavaInfo.notifyPropertyChanged(JavaInfo.java:5584)
at com.swtdesigner.gef.common.property.DesignerEditorPropertyComposite.handleRootNodeSelected(DesignerEditorPropertyComposite.java:662)
at com.swtdesigner.gef.common.property.DesignerEditorPropertyComposite.updatePropertyComposite(DesignerEditorPropertyComposite.java:865)
at com.swtdesigner.gef.DesignerEditor.parseCompilationUnit(DesignerEditor.java:1170)
at com.swtdesigner.gef.DesignerEditor$17.execute(DesignerEditor.java:1072)
at com.swtdesigner.model.swing.properties.custom.DesignTimeHelper.execute(DesignTimeHelper.java:54)
at com.swtdesigner.gef.DesignerEditor.handleActivate(DesignerEditor.java:1066)
at com.swtdesigner.gef.DesignerEditor.handleActivate(DesignerEditor.java:1059)
at com.swtdesigner.editors.MultiPageEditor.showDesignEditor(MultiPageEditor.java:426)
at com.swtdesigner.editors.MultiPageEditor$2.widgetSelected(MultiPageEditor.java:196)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:227)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:952)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:976)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:961)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:720)
at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:3236)
at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:2011)
at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:316)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:952)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3758)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3369)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2392)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2356)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2222)
at org.eclipse.ui.internal.Workbench$4.run(Workbench.java:474)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:288)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:469)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:106)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:193)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:106)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:76)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:362)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:175)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:564)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:504)
at org.eclipse.equinox.launcher.Main.run(Main.java:1251)
at org.eclipse.equinox.launcher.Main.main(Main.java:1227)
Caused by: java.lang.NoClassDefFoundError: Could not initialize class net.mygwt.ui.client.widget.Button
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.swtdesigner.model.swt.widgets.ConstructorSourcePropertiesHelper.createObject(ConstructorSourcePropertiesHelper.java:271)
... 52 more

[Eric Clayberg]

And then tried to net.mygwt.ui.client.widget.Button widget to the root panel and for the following error, which seem like caused by NoClassDefFoundError upon Button class initialization (see below). Even visual editor shows that error I can run the app with GWT shell and can see MyGWT button in the shell. Do you have any clue what could be wrong?

Yes. We had added an earlier hack to specifically work around MyGWT's non standard naming of its MyDOMIEImpl class. It appears that the MyGWT build corrects that problem, so the hack we added is no longer needed. We have now removed that hack and the MyGWT widgets appear to be showing up OK (I tried Button and List).

With the addition of default constructors and proper accessors, most of the simple MyGWT widgets should work. Complex MyGWT widgets (like containers or tables) will still need to have specific edit-time support added to GWT Designer (which we fully intend to do once the MyGWT API stabilizes) just as we did for the basic GWT panels and widgets.