Ext-GWT TreeGrid indiretamente chama um callback GWT-RPC? Por quê?

Question

Eu estou usando GWT-RPC para preencher Ext-GWT TreeGrids com dados de um servidor. Eu estou usando 4 retornos de chamada para preencher 6 TreeGrids. Como a chamada de retorno modifica função onSuccess o TreeGrid por inserir linhas, o TreeGridView precisa para tornar as linhas. A classe de retorno de chamada é chamado MainPnlSummaryTablesAsyncCallback.

Por alguma razão, quando ele precisa para determinar offsetHeight do scroller do TreeGridView via JSNI, onSuccess ou onFailure é chamado em outra instância da chamada de retorno no rastreamento de pilha. Uma cópia do rastreamento de pilha que eu encontrei é abaixo.

Não é este realmente estranho? Por que isso está acontecendo?

FYI Eu estou usando Ext-GWT 2.0.1 e 1.7.0 GWT e estou usando o navegador modo hospedado para depurar isso, embora eu tenho certeza que este é um problema para o modo web.

PnlSummaryClientDebug_as10node6 [Java Application]  
com.google.gwt.dev.HostedMode at localhost:3595 
    Thread [main] (Suspended (breakpoint at line 403 in MainPage$MainPnlSummaryTablesAsyncCallback))    
        MainPage$8(MainPage$MainPnlSummaryTablesAsyncCallback).onSuccess(GWTPair<AggregateStringGWTTable,AggregateStringGWTTable>) line: 403    
        MainPage$8(MainPage$MainPnlSummaryTablesAsyncCallback).onSuccess(Object) line: 1    
        RequestCallbackAdapter<T>.onResponseReceived(Request, Response) line: 215   
        Request.fireOnResponseReceivedImpl(RequestCallback) line: 264   
        Request.fireOnResponseReceivedAndCatch(GWT$UncaughtExceptionHandler, RequestCallback) line: 236 
        Request.fireOnResponseReceived(RequestCallback) line: 227   
        NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method] [local variables unavailable]    
        NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39  
        DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25  
        Method.invoke(Object, Object...) line: 597  
        MethodAdaptor.invoke(Object, Object...) line: 103   
        IDispatchImpl.callMethod(CompilingClassLoader, Object, Variant[], MethodAdaptor) line: 126  
        IDispatchProxy.invoke(int, int, Variant[]) line: 155    
        IDispatchProxy(IDispatchImpl).Invoke(int, int, int, int, int, int, int, int) line: 294  
        IDispatchProxy(IDispatchImpl).method6(int[]) line: 194  
        COMObject.callback6(int[]) line: 117    
        COM.VtblCall(int, int, int, GUID, int, int, DISPPARAMS, int, EXCEPINFO, int[]) line: not available [native method]  
        IDispatch.Invoke(int, GUID, int, int, DISPPARAMS, int, EXCEPINFO, int[]) line: 64   
        OleAutomation.invoke(int, int, Variant[], int[], Variant) line: 493 
        OleAutomation.invoke(int, Variant[]) line: 417  
        ModuleSpaceIE6.doInvokeOnWindow(OleAutomation, String, Variant[]) line: 68  
        ModuleSpaceIE6.doInvoke(String, Object, Class<?>[], Object[]) line: 153 
        ModuleSpaceIE6(ModuleSpace).invokeNative(String, Object, Class<?>[], Object[]) line: 453    
        ModuleSpaceIE6(ModuleSpace).invokeNativeInt(String, Object, Class<?>[], Object[]) line: 207 
        JavaScriptHost.invokeNativeInt(String, Object, Class<?>[], Object[]) line: 75   
        Element$.getOffsetHeight$(Element) line: not available  
        El.getHeight(boolean) line: 984 
        TreeGridView(BufferView).getVisibleRowCount() line: 313 
        TreeGridView(BufferView).doRender(List<ColumnData>, List<ModelData>, int, int, boolean, boolean) line: 189  
        TreeGridView(BufferView).doRender(List<ColumnData>, List<ModelData>, int, int, boolean) line: 181   
        TreeGridView(GridView).renderRows(int, int) line: 1559  
        TreeGridView(GridView).insertRows(ListStore<ModelData>, int, int, boolean) line: 1242   
        TreeGridView(GridView).onAdd(ListStore<ModelData>, List<ModelData>, int) line: 1293 
        GridView$5.storeAdd(StoreEvent<ModelData>) line: 1179   
        GridView$5(StoreListener<M>).handleEvent(StoreEvent<M>) line: 22    
        GridView$5(StoreListener<M>).handleEvent(BaseEvent) line: 1 
        TreeGrid$2(BaseObservable).callListener(Listener<BaseEvent>, BaseEvent) line: 176   
        TreeGrid$2(BaseObservable).fireEvent(EventType, BaseEvent) line: 96 
        TreeGrid$2(ListStore<M>).insert(List<? extends M>, int, boolean) line: 467  
        TreeGrid$2(ListStore<M>).insert(List<? extends M>, int) line: 266   
        TreeGrid<M>.onAdd(TreeStoreEvent<M>) line: 430  
        TreeGrid$1.storeAdd(StoreEvent<M>) line: 123    
        TreeGrid$1(StoreListener<M>).handleEvent(StoreEvent<M>) line: 22    
        TreeGrid$1(StoreListener<M>).handleEvent(BaseEvent) line: 1 
        TreeStore<M>(BaseObservable).callListener(Listener<BaseEvent>, BaseEvent) line: 176 
        TreeStore<M>(BaseObservable).fireEvent(EventType, BaseEvent) line: 96   
        TreeStore<M>.doInsert(TreeModel, List<TreeModel>, int, boolean, boolean) line: 799  
        TreeStore<M>.insert(List<M>, int, boolean) line: 493    
        TreeStore<M>.add(List<M>, boolean) line: 163    
        TreeStore<M>.add(M, boolean) line: 174  
        PnlClientFactory.populatePnlDataTreeStore(AggregateStringGWTTable, TreeStore<BaseModel>) line: 42   
        MainPage$9(MainPage$MainPnlSummaryTablesAsyncCallback).onSuccess(GWTPair<AggregateStringGWTTable,AggregateStringGWTTable>) line: 403    
        MainPage$9(MainPage$MainPnlSummaryTablesAsyncCallback).onSuccess(Object) line: 1    
        RequestCallbackAdapter<T>.onResponseReceived(Request, Response) line: 215   
        Request.fireOnResponseReceivedImpl(RequestCallback) line: 264   
        Request.fireOnResponseReceivedAndCatch(GWT$UncaughtExceptionHandler, RequestCallback) line: 236 
        Request.fireOnResponseReceived(RequestCallback) line: 227   
        NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
        NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39  
        DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25  
        Method.invoke(Object, Object...) line: 597  
        MethodAdaptor.invoke(Object, Object...) line: 103   
        IDispatchImpl.callMethod(CompilingClassLoader, Object, Variant[], MethodAdaptor) line: 126  
        IDispatchProxy.invoke(int, int, Variant[]) line: 155    
        IDispatchProxy(IDispatchImpl).Invoke(int, int, int, int, int, int, int, int) line: 294  
        IDispatchProxy(IDispatchImpl).method6(int[]) line: 194  
        COMObject.callback6(int[]) line: 117    
        OS.DispatchMessageW(MSG) line: not available [native method]    
        OS.DispatchMessage(MSG) line: 1925  
        Display.readAndDispatch() line: 2966    
        HostedMode(SwtHostedModeBase).processEvents() line: 235 
        HostedMode(HostedModeBase).pumpEventLoop() line: 558    
        HostedMode(HostedModeBase).run() line: 405  
        HostedMode.main(String[]) line: 232 
C:\Program Files\Java\jdk1.6.0_06\bin\javaw.exe (Jul 29, 2009 2:11:16 PM)   

Answer 1

Ok, parece que o servidor estava jogando alguns NullPointerExceptions quando as chamadas RPC estavam sendo feitos ... ainda assim, eu não entendo por que o rastreamento de pilha do lado do cliente olhou como este (olha o tipo de enganosa, como se dois empilhar traços sangraram para o outro).