问题
What I actually want is two PrimeFaces <p:pickList>s that get validated with OmniFaces' <o:validateAll> component. Note, that validating a pickList with <o:validateAll> has a problem, which can be solved as described in issue 488 in the OmniFaces issue tracker.
So a very simple example of my requirement looks like this:
<h:form id="form1">
<p:messages id="messages">
<p:autoUpdate/>
</p:messages>
<p:pickList id="pick1" value="#{dummy.dualListModel}"
var="item" itemLabel="#{item}" itemValue="#{item}">
<p:ajax event="transfer"/>
</p:pickList>
<p:pickList id="pick2" value="#{dummy.dualListModel2}"
var="item" itemLabel="#{item}" itemValue="#{item}">
<p:ajax event="transfer"/>
</p:pickList>
<o:validateAll id="validPicks" components="pick1 pick2"
message="all values required!" />
<h:commandButton id="done" value="Done" action="#{dummy.action1}"/>
</h:form>
<h:form id="theOtherForm">
<h:commandButton id="otherFormAction" value="Action in other form"
action="#{dummy.action2}"/>
</h:form>
The dummy backing-bean behind just provides getters/setters for the two dualListModel properties and the action-methods that do nothing.
When I run this code and leave at least one pickList empty, submitting the Done-button brings up a validation failure as excepted. However, clicking the button in the other form after the validation failed, leads to a NullPointerException in the PickListRenderer. Here is the StackTrace:
Caused by:java.lang.NullPointerException
at org.primefaces.component.picklist.PickListRenderer.encodeMarkup(PickListRenderer.java:92)
at org.primefaces.component.picklist.PickListRenderer.encodeEnd(PickListRenderer.java:59)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:920)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:890)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:456)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:134)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
at org.omnifaces.viewhandler.OmniViewHandler.renderView(OmniViewHandler.java:119)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
[...]
Im using OmniFaces 2.7 and PrimeFaces 6.2.
Please note, that I'm using a custom renderer for the PickList that overrides getConvertedValue(), as described in the linked issue from above. However, this does not change behavior of the renderer in any way that should effect this bug. It just makes <o:validateAll> recognize that the pickList is empty.
This seems like a bug to me, but I'm not sure if it is a bug in OmniFaces or in PrimeFaces. Anyone got any idea?
Workaround
As a workaround one could add the required="true" attribute to all of the pickLists.
Update
The same problem exists with PrimeFaces 7.0 (just the line numbers differ a bit).
In addition I produced another NPE with the above code and PrimeFaces 7.0, when sumbitting empty picklists via "done" and then transfering an item in one of the picklist to the target list.
The other exception occurs here:
Caused by:java.lang.NullPointerException
at org.primefaces.component.picklist.PickList.validateValue(PickList.java:140)
at javax.faces.component.UIInput.validate(UIInput.java:982)
at org.primefaces.component.picklist.PickList.validate(PickList.java:181)
at javax.faces.component.UIInput.executeValidate(UIInput.java:1248)
at javax.faces.component.UIInput.processValidators(UIInput.java:712)
at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:575)
at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1689)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
at javax.faces.component.UIForm.visitTree(UIForm.java:371)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:403)
at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:266)
at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:63)
at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:219)
at org.omnifaces.context.OmniPartialViewContext.processPartial(OmniPartialViewContext.java:124)
at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1193)
at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
In the corresponding code, the value of oldModel, which is initialized via getValue() is null.
回答1:
Issue verified and reported on GitHub: https://github.com/primefaces/primefaces/issues/4756
I submitted a fix which will hopefully be included in PF 7.0.2 and PF 7.1
https://github.com/primefaces/primefaces/pull/4759
回答2:
As Melloware wrote, the issue was reported as PrimeFaces issue #4756. It turned out, that the problem only exists with Mojarra (tested with 2.2.17, 2.2.18, 2.2.19 and 2.3.9) and not with MyFaces. So another issue was create: Mojarra #4398.
来源：https://stackoverflow.com/questions/54826563/primefaces-picklist-with-omnifaces-validateall-leads-to-nullpointerexception