Problem in obtaining collection of parameters onto my backing bean

Question

Hi All,
I am working on a page 'browse.jsp' inside Alfresco CMS to implement a customization of mine wherin in the "details" view, inclusion of checkboxes besides the document names and their checking and submission will result in thier display in a subsequent JSP.
Here is my code snippet from line no 411 of 'browse.jsp'
BeanForSendMultiple.java is my backing bean.
<%-- Primary column for details view mode --%>
<a:column id="col10" primary="true" style="padding:2px;text-align:left" rendered="#{BrowseBean.browseViewMode == 'details'}">
<f:facet name="header">
<a:sortLink id="col10-sort" label="#{msg.name}" value="name" mode="case-insensitive" styleClass="header"/>
</f:facet>
<h:dataTable binding="#{BeanForSendMultiple.dataTable}"
                             value="#{BeanForSendMultiple.nameDetails}" var="loc">
                    <h:column>
                        <h:selectBooleanCheckbox value="#{loc.selected}"/>
                        <h:outputText value="#{loc.docContentName}"/>
                    </h:column>
                </h:dataTable>
<a:actionLink id="col10-act2" value="#{r.name}" href="#{r.url}" target="new" >
<f:param name="documentDetails" value="#{r.name}" />
</a:actionLink>
<r:lockIcon id="col10-lock" value="#{r.nodeRef}" align="absmiddle" />
<h:outputLabel id="col10-lang" value="#{r.lang}" styleClass="langCode" rendered="#{r.lang != null}" />
<r:nodeInfo id="col10-info" value="#{r.id}">
<h:graphicImage id="col10-img" url="/images/icons/popup.gif" styleClass="popupImage" width="16" height="16" />
</r:nodeInfo>
</a:column>Here is my backing bean BeanForSendMultiple
public class BeanForSendMultiple {
    private List<NamesDetails> nameDetails;
    private String []documentDetails;
    private HtmlDataTable dataTable;
    private NamesDetails nameFurtherDetails = new NamesDetails();
    public BeanForSendMultiple(){
        nameDetails = new ArrayList<NamesDetails>();   
           NamesDetails nameFurtherDetails1 = new NamesDetails(); 
           for(int k=0;k<=documentDetails.length;k++){
               nameFurtherDetails1.setDocContentName(documentDetails[k]);                  
           nameDetails.add(nameFurtherDetails1);
    public HtmlDataTable getDataTable() {
        return dataTable;
    public void setDataTable(HtmlDataTable dataTable) {
        this.dataTable = dataTable;
     public List<NamesDetails> getNameDetails() {
        return nameDetails;
       public void setNameDetails(List<NamesDetails> nameDetails) {
        this.nameDetails = nameDetails;
       public String submit(){
        Iterator iterator = nameDetails.iterator();
        while (iterator.hasNext())
            nameFurtherDetails = (NamesDetails)iterator.next();
            System.out.print(nameFurtherDetails.isSelected());
            System.out.print(nameFurtherDetails.getDocContentName());
        return "dataTableCheckBox";
     public String[] getDocumentDetails() {
       return documentDetails;
       public void setDocumentDetails(String documentDetails[]) {
        this.documentDetails = documentDetails;
}and here are the getters and setters for the document
public class NamesDetails implements Serializable
    private static final long serialVersionUID = 7526471155622776147L;
    private boolean selected;
    private String docContentName;
    public boolean isSelected() {
        return selected;
     public void setSelected(boolean selected) {
        this.selected = selected;
     public String getDocContentName() {
       return docContentName;
       public void setDocContentName(String docContentName) {
        this.docContentName = docContentName;
}But on running the application i am getting the following stack trace: The issue being a NullPointer exception in obtaining documentDetails.length from the BeanForSendMultiple
javax.faces.FacesException: An exception occurred processing JSP page /jsp/browse/browse.jsp at line 430
427: <a:sortLink id="col10-sort" label="#{msg.name}" value="name" mode="case-insensitive" styleClass="header"/>
428: </f:facet>
429:
430: <h:dataTable binding="#{BeanForSendMultiple.dataTable}"
431: value="#{BeanForSendMultiple.nameDetails}" var="loc">
432: <h:column>
433: <h:selectBooleanCheckbox value="#{loc.selected}"/>
Stacktrace:
caused by:
org.apache.jasper.JasperException: An exception occurred processing JSP page /jsp/browse/browse.jsp at line 430
427: <a:sortLink id="col10-sort" label="#{msg.name}" value="name" mode="case-insensitive" styleClass="header"/>
428: </f:facet>
429:
430: <h:dataTable binding="#{BeanForSendMultiple.dataTable}"
431: value="#{BeanForSendMultiple.nameDetails}" var="loc">
432: <h:column>
433: <h:selectBooleanCheckbox value="#{loc.selected}"/>
Stacktrace:
caused by:
javax.faces.el.EvaluationException: Cannot get value for expression '#{BeanForSendMultiple.dataTable}'
caused by:
java.lang.NullPointerException
Hide Details
javax.faces.FacesException: An exception occurred processing JSP page /jsp/browse/browse.jsp at line 430
427: <a:sortLink id="col10-sort" label="#{msg.name}" value="name" mode="case-insensitive" styleClass="header"/>
428: </f:facet>
429:
430: <h:dataTable binding="#{BeanForSendMultiple.dataTable}"
431: value="#{BeanForSendMultiple.nameDetails}" var="loc">
432: <h:column>
433: <h:selectBooleanCheckbox value="#{loc.selected}"/>
Caused by: java.lang.NullPointerException
at org.alfresco.web.bean.BeanForSendMultiple.<init>(BeanForSendMultiple.java:108)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
.....Could any one please guide me on my approach where i am missing out.
Thank You

Answer 1

You can use:
  public Object resolveExpression(String expression)
    FacesContext ctx = getFacesContext();
    Application app = ctx.getApplication();
    ValueBinding bind = app.createValueBinding(expression);
    return bind.getValue(ctx);
  }and
BindingContainer bc = (BindingContainer) resolveExpression("#{bindings}");John