Summary: I have been developing a somewhat complex JSF form with a list of documents, and now want to add a button in each row of that list, which will allow you to download the document file. Primefaces offers an attravtive solution to this, so I am gradually converting the whole page to use primefaces, but for now I have just converted the table of documents - this works well, although it looks odd. My problem is that I get an exception, when I add the p:commandButton, and I don't even know what it means - as far as I can tell, I am following the examples I have been able to find, including on primefaces' showcases:
org.primefaces.component.column.Column cannot be cast to javax.faces.component.ActionSource
Here are the table details
<h:form id="doclistform">
<p:dataTable value="#{documentsController.documentList}" var="doclst"
id="doclist">
<!-- innocent columns -->
<p:column>
<f:facet name="header">
<h:outputText value="Download"/>
</f:facet>
<p:fileDownload value="#{doclst.docfile}"/>
</p:column>
</p:dataTable>
</h:form>
The exception in the server.log:
[2017-11-29T09:27:33.935+0000] [glassfish 5.0] [FATAL] [jsf.context.exception.handler.log] [javax.enterprise.resource.webcontainer.jsf.context] [tid: _ThreadID=31 _ThreadName=http-listener-1(5)] [timeMillis: 1511947653935] [levelValue: 1100] [[
JSF1073: java.lang.ClassCastException caught during processing of RENDER_RESPONSE 6 : UIComponent-ClientId=, Message=org.primefaces.component.column.Column cannot be cast to javax.faces.component.ActionSource]]
[2017-11-29T09:27:33.936+0000] [glassfish 5.0] [FATAL] [] [javax.enterprise.resource.webcontainer.jsf.context] [tid: _ThreadID=31 _ThreadName=http-listener-1(5)] [timeMillis: 1511947653936] [levelValue: 1100] [[
org.primefaces.component.column.Column cannot be cast to javax.faces.component.ActionSource
java.lang.ClassCastException: org.primefaces.component.column.Column cannot be cast to javax.faces.component.ActionSource
at org.primefaces.component.filedownload.FileDownloadTagHandler.apply(FileDownloadTagHandler.java:56)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:161)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:135)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:96)
at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:94)
at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:88)
at com.sun.faces.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:162)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.buildView(FaceletViewHandlingStrategy.java:381)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:102)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:223)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:671)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1580)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:258)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:652)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:591)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:371)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:238)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:463)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:168)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:242)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:539)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:593)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:573)
at java.lang.Thread.run(Thread.java:745)
If you look at PrimeFaces showcase, you'll notice that <p:fileDowload> is embedded in a <p:commandButton> tag: the file download need an action source (like the error mentioned) to trigger the download.
Just wrap your p:fileDownload with a p:commandButton.
<p:column>
<f:facet name="header">
<h:outputText value="Download"/>
</f:facet>
<p:commandButton value="Download" ajax="false">
<p:fileDownload value="#{doclst.docfile}"/>
</p:commandButton>
</p:column>
When handling with file download, ensure that:
- the
p:commandButtonhasajax="false"attribute- the
p:fileDownloadvalue is not theFileobject but aStreamedContent
Unrelated to download but you can simplify your code by using the headerText attribute of p:column:
<p:column headerText="Download">
<p:commandButton value="Download" ajax="false">
<p:fileDownload value="#{doclst.docfile}"/>
</p:commandButton>
</p:column>