[ http://issues.apache.org/jira/browse/MYFACES-855?page=all ]
Martin Marinschek updated MYFACES-855:
--------------------------------------
Status: Open (was: Patch Available)
> FacesException: Cannot get value for expression '...' when expression is valid
> ------------------------------------------------------------------------------
>
> Key: MYFACES-855
> URL: http://issues.apache.org/jira/browse/MYFACES-855
> Project: MyFaces Core
> Issue Type: Bug
> Components: General
> Affects Versions: 1.1.0
> Environment: IBM WebSphere 5.1.1.3, Windows Server 2003, JDK 1.4.2,
> Hibernate 3.0
> Reporter: Brett Sabell
>
> I have a dataTable whose value is a List property ( ruleInstanceList ) in a
> backing bean ( listRuleInstancesBean ). The List is populated by Hibernate
> 3.0, and is accessible via its own public getter/setter methods in the bean (
> getRuleInstanceList() and setRuleInstanceList() ). However, when I attempt to
> display the page I receive the following message ( instead of the dataTable ):
> Error 500: Cannot get value for expression '#{ruleInstanceRow.ruleInstanceId}'
> "ruleInstanceRow" is the var set up for the dataTable, and is of type
> RuleInstance ( a class I wrote ). This class contains a property called
> "ruleInstanceId", which has public getter/setter methods. Other columns are
> included in the dataTable and are mapped to other properties in
> ruleInstanceRow, but ruleInstanceId is the first; I removed it, tried again,
> and received the same error for the next column.
> In the systemOut.log file for WebSphere, the following exception stack trace
> was dumped:
> [22/11/05 10:51:49:844 EST] 3a5327e8 WebGroup E SRVE0026E: [Servlet
> Error]-[Cannot get value for expression
> '#{ruleInstanceRow.ruleInstanceId}']: javax.faces.FacesException:
> Cannot get value for expression '#{ruleInstanceRow.ruleInstanceId}'
> at
> org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:421)
> at
> org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:234)
> at
> org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:300)
> at javax.faces.webapp.FacesServlet.service(FacesServlet.java:95)
> at
> com.ibm.ws.webcontainer.servlet.StrictServletInstance.doService(StrictServletInstance.java:110)
> at
> com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet._service(StrictLifecycleServlet.java:174)
> at
> com.ibm.ws.webcontainer.servlet.IdleServletState.service(StrictLifecycleServlet.java:313)
> at
> com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet.service(StrictLifecycleServlet.java:116)
> at
> com.ibm.ws.webcontainer.servlet.ServletInstance.service(ServletInstance.java:283)
> at
> com.ibm.ws.webcontainer.servlet.ValidServletReferenceState.dispatch(ValidServletReferenceState.java:42)
> at
> com.ibm.ws.webcontainer.servlet.ServletInstanceReference.dispatch(ServletInstanceReference.java:40)
> at
> com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:76)
> at com.thenational.filter.RoleFilter.doFilter(RoleFilter.java:107)
> at
> com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:132)
> at
> com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:71)
> at jcifs.http.NtlmHttpFilter.doFilter(NtlmHttpFilter.java:118)
> at
> com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:132)
> at
> com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:71)
> at
> com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.handleWebAppDispatch(WebAppRequestDispatcher.java:1040)
> at
> com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.dispatch(WebAppRequestDispatcher.java:600)
> at
> com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java:201)
> at
> com.ibm.ws.webcontainer.srt.WebAppInvoker.doForward(WebAppInvoker.java:125)
> at
> com.ibm.ws.webcontainer.srt.WebAppInvoker.handleInvocationHook(WebAppInvoker.java:286)
> at
> com.ibm.ws.webcontainer.cache.invocation.CachedInvocation.handleInvocation(CachedInvocation.java:71)
> at
> com.ibm.ws.webcontainer.srp.ServletRequestProcessor.dispatchByURI(ServletRequestProcessor.java:182)
> at
> com.ibm.ws.webcontainer.oselistener.OSEListenerDispatcher.service(OSEListener.java:334)
> at
> com.ibm.ws.webcontainer.http.HttpConnection.handleRequest(HttpConnection.java:56)
> at
> com.ibm.ws.http.HttpConnection.readAndHandleRequest(HttpConnection.java:624)
> at com.ibm.ws.http.HttpConnection.run(HttpConnection.java:458)
> at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:912)
> Caused by: javax.servlet.ServletException: Cannot get value for expression
> '#{ruleInstanceRow.ruleInstanceId}'
> at
> com.ibm.ws.webcontainer.jsp.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:416)
> at
> com.ibm.ws.webcontainer.jsp.servlet.JspServlet.serviceJspFile(JspServlet.java:683)
> at
> com.ibm.ws.webcontainer.jsp.servlet.JspServlet.service(JspServlet.java:781)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> at
> com.ibm.ws.webcontainer.servlet.StrictServletInstance.doService(StrictServletInstance.java:110)
> at
> com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet._service(StrictLifecycleServlet.java:174)
> at
> com.ibm.ws.webcontainer.servlet.IdleServletState.service(StrictLifecycleServlet.java:313)
> at
> com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet.service(StrictLifecycleServlet.java:116)
> at
> com.ibm.ws.webcontainer.servlet.ServletInstance.service(ServletInstance.java:283)
> at
> com.ibm.ws.webcontainer.servlet.ValidServletReferenceState.dispatch(ValidServletReferenceState.java:42)
> at
> com.ibm.ws.webcontainer.servlet.ServletInstanceReference.dispatch(ServletInstanceReference.java:40)
> at
> com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.handleWebAppDispatch(WebAppRequestDispatcher.java:1044)
> at
> com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.dispatch(WebAppRequestDispatcher.java:600)
> at
> com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java:201)
> at
> org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:415)
> ... 29 more
> The backing bean is configured in my faces-config.xml file, with the correct
> package/class. I put in some debugging statements in my getRuleInstanceList()
> method, and determined that a valid non-null List is correctly being returned
> by Hibernate, and it contains one element of type RuleInstance, which has all
> of the properties that are referenced in the dataTable columns. Therefore, I
> cannot see why MyFaces can't get the values!
> Here are the relevant snippets of code:
> faces-config.xml
> =============
> <managed-bean>
> <managed-bean-name>listRuleInstancesBean</managed-bean-name>
>
> <managed-bean-class>com.thenational.otkr.dmi.beans.ListRuleInstancesBean</managed-bean-class>
> <managed-bean-scope>request</managed-bean-scope>
> </managed-bean>
> ListRuleInstancesBean.java
> ======================
> public class ListRuleInstancesBean extends BaseBean
> {
> protected UIData ruleInstanceTable;
> private List ruleInstanceList;
> private static final Logger logger =
> Logger.getLogger(ListRuleInstancesBean.class);
>
> public List getRuleInstanceList()
> {
> if (ruleInstanceList == null)
> {
> ruleInstanceList = new ArrayList(0);
>
> try
> {
> ruleInstanceList =
> getDao().getAllRuleInstances(); // getDao() returns a Hibernate3 DAO object
> }
> catch (Exception e)
> {
> // Log error
> logger.error("Exception in
> getRuleInstanceList(): " + e.toString());
> }
> }
>
> return ruleInstanceList;
> }
>
> public void setRuleInstanceList(List ruleInstanceList)
> {
> this.ruleInstanceList = ruleInstanceList;
> }
> public UIData getRuleInstanceTable()
> {
> return ruleInstanceTable;
> }
> public void setRuleInstanceTable(UIData ruleInstanceTable)
> {
> this.ruleInstanceTable = ruleInstanceTable;
> }
> }
> RuleInstance.java
> ==============
> public class RuleInstance extends ModelBase implements Comparable
> {
> private Long ruleInstanceId;
> private Long ruleId;
> private String ruleInstanceGroup;
> private Long schemaInstanceId;
> private Long deskId;
> private Long sourceSystemId;
> private Integer severity;
> private boolean activeFlag = false;
> public Long getRuleInstanceId() {
> return ruleInstanceId;
> }
> public void setRuleInstanceId(Long ruleInstanceId) {
> this.ruleInstanceId = ruleInstanceId;
> }
> public Long getRuleId() {
> return ruleId;
> }
> public void setRuleId(Long ruleId) {
> this.ruleId = ruleId;
> }
> public String getRuleInstanceGroup() {
> return ruleInstanceGroup;
> }
> public void setRuleInstanceGroup(String ruleInstanceGroup) {
> this.ruleInstanceGroup = ruleInstanceGroup;
> }
> public Long getSchemaInstanceId() {
> return schemaInstanceId;
> }
> public void setSchemaInstanceId(Long schemaInstanceId) {
> this.schemaInstanceId = schemaInstanceId;
> }
> public Long getDeskId() {
> return deskId;
> }
> public void setDeskId(Long deskId) {
> this.deskId = deskId;
> }
> public Long getSourceSystemId() {
> return sourceSystemId;
> }
> public void setSourceSystemId(Long sourceSystemId) {
> this.sourceSystemId = sourceSystemId;
> }
> public Integer getSeverity() {
> return severity;
> }
> public void setSeverity(Integer severity) {
> this.severity = severity;
> }
> public boolean isActiveFlag() {
> return activeFlag;
> }
>
> public boolean getActiveFlag() {
> return activeFlag;
> }
> public void setActiveFlag(boolean activeFlag) {
> this.activeFlag = activeFlag;
> }
> }
> listRuleInstances.jsp
> =================
> <h:dataTable id="listRuleInstancesTable"
> value="#{listRuleInstancesBean.ruleInstanceList}"
> binding="#{listRuleInstancesBean.ruleInstanceTable}"
> var="ruleInstanceRow"
> headerClass="DashPartTitle"
> rowClasses="DashPartBody"
> cellspacing="0"
> cellpadding="2"
> frame="border"
> rules="all">
> <h:column>
> <f:facet name="header">
> <h:outputText value="Rule Instance Id"/>
> </f:facet>
> <h:outputText value="#{ruleInstanceRow.ruleInstanceId}"/>
> </h:column>
> <h:column>
> <f:facet name="header">
> <h:outputText value="Rule Instance Group"/>
> </f:facet>
> <h:outputText value="#{ruleInstanceRow.ruleInstanceGroup}"/>
> </h:column>
> <h:column>
> <f:facet name="header">
> <h:outputText value="Severity"/>
> </f:facet>
> <h:outputText
> value="ERROR"
> rendered="#{ruleInstanceRow.severity == '0'}"/>
> <h:outputText
> value="WARN"
> rendered="#{ruleInstanceRow.severity == '1'}"/>
> <h:outputText
> value="INFO"
> rendered="#{ruleInstanceRow.severity == '2'}"/>
> </h:column>
> <h:column>
> <f:facet name="header">
> <h:outputText value="Active"/>
> </f:facet>
> <h:outputText
> value="Yes"
> rendered="#{ruleInstanceRow.activeFlag == 'true'}"/>
> <h:outputText
> value="No"
> rendered="#{ruleInstanceRow.activeFlag == 'false'}"/>
> </h:column>
> </h:dataTable>
> I have other dataTable's in my application, all of which follow the exact
> same pattern as this, and all of which work correctly. Thinking that there
> might have been a problem connecting the JSP page to the backing bean, I
> changed the getAllRuleInstances() method above to return a List of different
> classes, and changed the column references in the dataTable to the different
> class, and the dataTable worked correctly. This tells me that MyFaces may
> have a problem with the RuleInstance class, but without more detailed
> exception information I can't see what that might be.
> Just to clarify, I am using JDK 1.4.2. I have seen a dataTable example that
> used a paramaterized List ( List<...> ) to tell Java what class each element
> would be an instance of, which might aid MyFaces in displaying the dataTable.
> I understand that paramaterized types are only supported in JDK 1.5+, so I
> cannot go down this path.
> This problem seems to defy logic, and I have been beating my head against the
> wall trying to solve it. Is there something hidden away that can cause a
> dataTable to throw this exception for no apparent reason?
> Any ideas? I appreciate any time you can spend looking at this, so thanks in
> advance.
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