NullPointerException when removing node in tree

[jeffzzang]

I am using <rich:tree > with a few nested <rich:treeNodesAdaptors> and when I remove one of the nodes from the tree and then re-render the tree, I get the following exception:

java.lang.NullPointerException
at org.richfaces.model.StackingTreeModel.walk(StackingTreeModel.java:361)
at org.richfaces.model.StackingTreeModel.walkModel(StackingTreeModel.java:457)
at org.richfaces.component.UITree.walkModel(UITree.java:357)
at org.richfaces.component.state.TreeState.visitNodes(TreeState.java:200)
at org.richfaces.component.state.TreeState.expandNode(TreeState.java:262)
at org.richfaces.component.state.events.ExpandNodeCommandEvent.execute(ExpandNodeCommandEvent.java:48)
at org.richfaces.component.state.events.TreeStateCommandEvent.processListener(TreeStateCommandEvent.java:59)
at org.richfaces.component.UITree.broadcast(UITree.java:489)
at org.ajax4jsf.component.UIInclude.broadcast(UIInclude.java:138)
at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:184)
at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:162)
at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:350)
at org.apache.myfaces.lifecycle.InvokeApplicationExecutor.execute(InvokeApplicationExecutor.java:32)
at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:95)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:70)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:139)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:141)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:281)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:147)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

The way I remove it is to see which "row" was removed, remove it from the underlying collection, and then repopulate the underlying Collection for the outer-most treeNodesAdaptor. Anyone have any ideas?

[jeffzzang]

Update:

I've also come across the following exception when adding nodes to the tree. Also note, this only happens if I add nodes in certain places.

java.lang.IllegalStateException
at org.richfaces.model.StackingTreeModel.getInternalModelById(StackingTreeModel.java:337)
at org.richfaces.model.StackingTreeModel.doSetupKey(StackingTreeModel.java:134)
at org.richfaces.model.StackingTreeModel.doSetupKey(StackingTreeModel.java:150)
at org.richfaces.model.StackingTreeModel.doSetupKey(StackingTreeModel.java:150)
at org.richfaces.model.StackingTreeModel.setupKey(StackingTreeModel.java:171)
at org.richfaces.model.StackingTreeModel.setRowKey(StackingTreeModel.java:470)
at org.ajax4jsf.component.UIDataAdaptor.setRowKey(UIDataAdaptor.java:319)
at org.ajax4jsf.component.UIDataAdaptor.setRowKey(UIDataAdaptor.java:299)
at org.richfaces.renderkit.TreeRendererBase.encodeSelectionStateInput(TreeRendererBase.java:547)
at org.richfaces.renderkit.html.TreeRenderer.doEncodeEnd(TreeRenderer.java:216)
at org.richfaces.renderkit.html.TreeRenderer.doEncodeEnd(TreeRenderer.java:239)
at org.ajax4jsf.renderkit.RendererBase.encodeEnd(RendererBase.java:135)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:539)
at javax.faces.component.UIData.encodeEnd(UIData.java:573)
at org.ajax4jsf.renderkit.RendererBase.renderChild(RendererBase.java:286)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:143)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxChildren(AjaxChildrenRenderer.java:86)
at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:134)
at org.ajax4jsf.renderkit.AjaxContainerRenderer.encodeAjax(AjaxContainerRenderer.java:122)
at org.ajax4jsf.component.UIAjaxRegion.encodeAjax(UIAjaxRegion.java:239)
at org.ajax4jsf.context.AjaxContextImpl.renderAjaxRegion(AjaxContextImpl.java:289)
at org.ajax4jsf.context.AjaxContextImpl$2.invoke(AjaxContextImpl.java:204)
at org.ajax4jsf.context.JsfOneOneInvoker.invokeOnComponent(JsfOneOneInvoker.java:78)
at org.ajax4jsf.context.JsfOneOneInvoker.invokeOnComponent(JsfOneOneInvoker.java:83)
at org.ajax4jsf.context.JsfOneOneInvoker.invokeOnComponent(JsfOneOneInvoker.java:83)
at org.ajax4jsf.context.JsfOneOneInvoker.invokeOnComponent(JsfOneOneInvoker.java:83)
at org.ajax4jsf.context.JsfOneOneInvoker.invokeOnComponent(JsfOneOneInvoker.java:83)
at org.ajax4jsf.context.JsfOneOneInvoker.invokeOnComponent(JsfOneOneInvoker.java:83)
at org.ajax4jsf.context.AjaxContextImpl.invokeOnComponent(AjaxContextImpl.java:160)
at org.ajax4jsf.context.AjaxContextImpl.renderSubmittedAjaxRegion(AjaxContextImpl.java:218)
at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:239)
at org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:41)
at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:132)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:140)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:141)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:281)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:147)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

It looks like in the StackingTreeModel class, the error is being thrown here:

private StackingTreeModel getInternalModelById(String id) {
StackingTreeModel model = getModelById(id);
if (model.isActive()) {
return model;
}

throw new IllegalStateException();
}

As you can see, the IllegalStateException only gets thrown if model.isActive() return false. If we look at the isActive() method:

protected boolean isActive() {
return true;
}

so how is this happening? I looked through the source and didn't find any subclasses of the StackingTreeModel that overrode isActive. Any thoughts?

[jeffzzang]

I think I figured it out. I think what's happening is when you use switchType="client" the view tries to rebuild the tree locally (and expand/collapse the appropriate levels), and it chokes because I just removed one of the rows from the tree and it tries to expand that node I just removed. The reason I suspect this is because when I add/remove elements to the tree, it sometimes expanded/collapsed the wrong levels.

I tried changing it to switchType="ajax" and it works, but this is not desirable as a roundtrip to the server is not really necessary for expanding and collapsing nodes.

The one other modification I had to perform was to call reRender on the <h:panelGrid/> that surrounded the <rich:tree/>. I've noticed this in other places as well, can someone explain this to me?

For example:

<h:panelGrid columns="1" id="scheduleTreePanel">
 <rich:tree id="scheduleTree" switchType="ajax" preserveModel="none" immediate="false" toggleOnClick="true">
 <rich:treeNodesAdaptor nodes="#{controller.scheduleNodes}" var="treeDates">
 <a4j:commandLink actionListener="#{controller.removeOtherEvent}" reRender="scheduleTree" >
 <h:outputText value="Remove"/>
 </a4j:commandLink>
 </rich:treeNodesAdaptor>
 </rich:tree>
</h:panelGrid>

If I have reRender="scheduleTree" as I have above, the code breaks. If, however, I set reRender to "scheduleTreePanel", it magically works. Anyone know what's going on?