Exception thrown while accessing HTML DataTable in backing bean - jsf

Question

I am building a simple application in JSF with the CrUD functionality. I am trying to implement edit functionality using the tomahawk component .I am unable to retrieve the selected row in my backing bean.
Here's my JSP file snip:
<t:dataTable id="data"
binding="#{selectOneRowList.dataTable}"
styleClass="scrollerTable"
headerClass="standardTable_Header"
footerClass="standardTable_Header"
rowClasses="standardTable_Row1,standardTable_Row2"
columnClasses="standardTable_Column,standardTable_ColumnCentered,standardTable_Column"
var="car"
value="#{selectOneRowList.list}"
sortColumn="#{selectOneRowList.sortColumn}"
sortAscending="#{selectOneRowList.sortAscending}"
preserveDataModel="false"
preserveSort="true"
preserveRowStates="true"
rows="10"
>
<h:column>
<f:facet name="header">
<h:outputText value="Select"/>
</f:facet>
<t:selectOneRow groupName="selection" id="hugo" value="#{selectOneRowList.selectedRowIndex}"
onchange="submit();" immediate="true"
valueChangeListener="#{selectOneRowList.processRowSelection}"/>
</h:column>
<h:column>
<f:facet name="header">
</f:facet>
<h:outputText value="#{car.id}" />
</h:column>
<h:column>
<f:facet name="header">
<h:outputText value="Cars" />
</f:facet>
<h:outputText value="#{car.type}" />
</h:column>
<t:column sortable="true">
<f:facet name="header">
<h:outputText value="Color" />
</f:facet>
<h:outputText value="#{car.color}" />
</t:column>
</t:dataTable>
Here's my backing bean SelectOneRowList.java :
public void editCar(ActionEvent event) {
System.out.println("Row number ## " + _selectedRowIndex.toString() + " selected!");
System.out.println("Datatable ::"+ dataTable);
System.out.println("Row Count ::" + dataTable.getRowCount());
dataItem = (SimpleCar) getDataTable().getRowData();
//selectedCar = (SimpleCar) _list.get(Integer.parseInt(_selectedRowIndex.toString()));
selectedCar = (SimpleCar) dataTable.getRowData();
System.out.println(dataTable.getRowData());
}
My DTO{Data Transfer Object} which is SimpleCar.java contains the variables ID, type, color and their respective setters/getters.
The dataItem variable is of type "SimpleCar". The dataTable is of type HTMLDataTable. I am able to get the the first 3 SOP's but the 4th SOP isn't printed. I receive the following exception on the server :
javax.faces.el.EvaluationException: Exception while invoking expression #{selectOneRowList.editCar}
org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:156)
javax.faces.component.UICommand.broadcast(UICommand.java:89)
javax.faces.component.UIViewRoot._broadcastForPhase(UIViewRoot.java:97)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:171)
org.apache.myfaces.lifecycle.InvokeApplicationExecutor.execute(InvokeApplicationExecutor.java:32)
org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:95)
org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:70)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:139)
org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:341)
On click of the edit button the editCar method in my backing bean is invoked. I need to get the data of the selected row in my backing bean. Why is the exception occurring ?
The above example is taken from the tomawhawk examples WAR distributed on the website. I have gone through many links including the ones on BalusC but none of them have helped.
Regards,

Answer 1

To use DataTable.getRowData() you would have to put the button tied to editCar() within the data table. So, on your JSP would need to add another column, such as:
...
<t:column sortable="true">
<f:facet name="header">
<h:outputText value="Color" />
</f:facet>
<h:outputText value="#{car.color}" />
</t:column>
<t:column sortable="false">
<h:commandButton value="Edit" action="#{selectOneRowList.editCar}" />
</t:column>
</t:dataTable>