An extra column of a query in an ADF Faces Table?

Question

Hi to all OTN Community...
I use ADF Faces, Toplink and EJB 3.0 in JDevelooper 10.1.3.1.0, and i have a question...
I need to show in an adf faces table, the result of a query like this
SELECT COLUMN1, COLUMN2, COUNT(*)
FROM TABLEX
GROUP BY COLUMN1, COLUMN2
I do this query in the TableX named queryes...and then i have acces to this named query in the dataControl, but, when i drag and drop the dataControl to a jsf page, this only shows the columns of the tableX. Then, i want to know, ¿How can i show the count(*) column in the page in a dataControl?
PD: i want to show in the adf faces table the same result if i execute that query in an sql client.
Thanx in advance...
Darklorddany

Answer 1

Darklorddany,
The solution to this is to add an additional method on your EJB 3.0 session-bean that exposes an dynamic TopLink report (projection) query.
The TopLink code within the method would leverage your existing TopLink mappings to do the query like:
        ReportQuery rq = new ReportQuery(Employee.class, new ExpressionBuilder());
        rq.addAttribute("firstName");
        rq.addAttribute("lastName");
        rq.addCount();
        rq.addGrouping("firstName");
        rq.addGrouping("lastName");
        List<ReportQueryResult> results = (List<ReportQueryResult>)session.executeQuery(rq);The ReportQueryResult objects are very generic map/row type containers that will not work well in your ADF binding layer. With JPA you can specify and ad-hoc Java class to contain such projection results that make them a little easier to use in clients. This functionality will be available in the next release of TopLink. Until then you will need to write some code to convert to your own result class for this query.
In my case I'll create a simple POJO like:
    public class EmployeeNameCount {
        private String firstName;
        private String lastName;
        private int count;
        public EmployeeNameCount(String firstName, String lastName, int count) {
            this.firstName = firstName;
            this.lastName = lastName;
            this.count = count;
        public String getFirstName() {
            return this.firstName;
        public String getLastName() {
            return this.lastName;
        public int getCount() {
            return this.count;
    }Now I combine the previous report query code into an EJB 3.0 session bean method:
    @TransactionAttribute(TransactionAttributeType.SUPPORTS)
    public List<EmployeeNameCount> findEmployeeNamesWithCount() {
        Session session = getSessionFactory().acquireSession();
        ReportQuery rq = new ReportQuery(Employee.class, new ExpressionBuilder());
        rq.addAttribute("firstName");
        rq.addAttribute("lastName");
        rq.addCount();
        rq.addGrouping("firstName");
        rq.addGrouping("lastName");
        List<ReportQueryResult> results = (List<ReportQueryResult>)session.executeQuery(rq);
        session.release();
        List<EmployeeNameCount> empNameCounts = new ArrayList<EmployeeNameCount>(results.size());
        for (ReportQueryResult rqr: results) {
            String fname = (String)rqr.getByIndex(0);
            String lname = (String)rqr.getByIndex(1);
            int count = ((Number) rqr.getByIndex(2)).intValue();
            empNameCounts.add(new EmployeeNameCount(fname, lname, count));   
        return empNameCounts;
    }You will also need to make sure the method exists on your EJB 3.0 session bean's interface as well. Then regenerate the data control for your session bean and you should have access to drag and drop this query with its results into your JSF pages.
As mentioned this use case will be much simpler and declarative in the next release.
Doug