Lazy loading in p:dataTable / p:dataGrid and f:setPropertyActionListener

Question

I have a <p:dataTable> as follows.

<p:dataTable var="row" value="#{testManagedBean.list}">
    <p:column>
        <h:outputText value="#{row.subCatId}"/>
    </p:column>

    <p:column>
        <p:commandLink process="@this">
            <h:outputText value="#{row.subCatName}"/>
            <f:setPropertyActionListener target="#{testManagedBean.subCatName}" value="#{row.subCatName}"/>
        </p:commandLink>
    </p:column>
</p:dataTable>

The corresponding RequestScoped managed bean is as follows.

@ManagedBean
@RequestScoped
public final class TestManagedBean
{
    @EJB
    private final TestBeanLocal testService=null;
    private List<SubCategory>list;
    private String subCatName;

    @PostConstruct
    private void init()
    {
        list=testService.getSubCategoryList();
    }

    public List<SubCategory> getList() {
        return list;
    }

    public String getSubCatName() {
        return subCatName;
    }

    public void setSubCatName(String subCatName) {
        System.out.println("setSubCatName() called : "+subCatName);
        this.subCatName = subCatName;
    }
}

When <p:commandLink> inside <p:dataTable> is clicked, the corresponding setter method associated with <f:setProperyActionListener> (setSubCatName()) is called and the value is correctly set to the target property which is subCatName in this managed bean.

_{I have avoided many things like paging to have a minimal example.}

---

Now, I need to populate this <p:dataTable> lazily. I'm changing this <p:dataTable> and the corresponding managed bean as follows.

<p:dataTable var="row" value="#{testManagedBean}" lazy="true" rows="10" rowIndexVar="rowIndex">
    <p:column>
        <h:outputText value="#{row.subCatId}"/>
    </p:column>

    <p:column>
        <p:commandLink process="@this">
            <h:outputText value="#{row.subCatName}"/>
            <f:setPropertyActionListener target="#{testManagedBean.subCatName}" value="#{row.subCatName}"/>
        </p:commandLink>
    </p:column>
</p:dataTable>

And the associated JSF managed is given below.

@ManagedBean
@RequestScoped
public final class TestManagedBean extends LazyDataModel<SubCategory> implements Serializable
{
    @EJB
    private final TestBeanLocal testService=null;
    private String subCatName;
    private static final long serialVersionUID = 1L;

    public String getSubCatName() {
        return subCatName;
    }

    public void setSubCatName(String subCatName) {
        System.out.println("setSubCatName() called : "+subCatName);
        this.subCatName = subCatName;
    }

    @Override
    public List<SubCategory> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String, String> filters)
    {
        setRowCount(4); //Just an example. Otherwise, fetch from the database.
        return testService.getSubCategoryList(first, pageSize, sortField, sortOrder, filters);
    }
}

Now, when <p:commandLink> inside <p:dataTable> is clicked, the corresponding setter method associated with <f:setProperyActionListener> (setSubCatName()) is not invoked.

The setSubCatName() is only invoked, when the managed bean is decorated with a broader scope like @ViewScoped (in case of lazy is set to true)

Why doesn't <f:setPropertyActionListener> work with a request scoped managed managed bean, when a <p:dataTable> (also true for <p:dataGrid>) is lazily loaded?

Is it mandatory to designate a managed bean with a broader than a request scope in such cases?

Answer 1

yes it is mandatory because the underlying model has to be the same instance. even if it has the same values it won't work.

like you, i've met this behavior: primefaces datatable lazy loading and commandbutton per row