Tapestry error: #does not contain a public constructor needed to autobuild

Question

I have a problem in displaying some Reviews from a Mysql Database through a list
The error:
Render queue error in SetupRender[Details:grid]: Failure reading parameter 'source' of component Details:grid: Class com.mycompany.licenta.data.InterfataRecenzii does not contain a public constructor needed to autobuild.

Can anyone help me to say what is wrong in this?
I hope it is understandable.

I also have another interface in my project to display another things from my database( and all are in the same package/ but even if i put this in other packages the error is still the same). Is that ok?

My code for the class with the list is:

package com.mycompany.licenta.datarecenzii;
import com.mycompany.licenta.datarecenzii.Recenzie;
import com.mycompany.licenta.datarecenzii.InterfataRecenzii;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import javax.naming.InitialContext;
import javax.sql.DataSource;

public class ListaRecenzii implements InterfataRecenzii{

private List<Recenzie> recenzii = new ArrayList<Recenzie>();

 public ListaRecenzii()
{
    //preluare recenzii din baza de date
     String flag="";
    String jndiname="jdbc/TestDB";
    DataSource dataSource=null;
    try{
        dataSource=(DataSource) new InitialContext().lookup("java:comp/env/" + jndiname);
        Connection con=dataSource.getConnection();
        Statement stm=con.createStatement();
        ResultSet rs=stm.executeQuery("select * from recenzii");
        ResultSetMetaData rsmd=rs.getMetaData();
        while(rs.next())
            {
                Recenzie recenzie=new Recenzie(rs.getInt("idhotel"),rs.getString("numeRecenzor"),rs.getInt("nivelIncredere"),rs.getString("recenzie"));
                   recenzii.add(recenzie);

            }


    }catch (Exception e){flag+=e.toString();}
    if (dataSource!=null)
        flag+="succes";

   // addRecenzie(new Recenzie(6, "mihai",8,"Vega este un hotel de 5 stele din Mamaia"));

}
public List<Recenzie> getAllRecenzii()
{
return recenzii;
}
public Recenzie getRecenzieByIdRecenzie(int idRecenzie)
{
for (Recenzie r : recenzii)
{
if (r.getIdRecenzie() == idRecenzie) return r;
}
return null;
}
public void addRecenzie(Recenzie r)
{
int newIdRecenzie = recenzii.size();
r.setIdRecenzie(newIdRecenzie);
recenzii.add(r);
}
}

My Interface:

<pre>package com.mycompany.licenta.datarecenzii;

import java.util.List;
public interface InterfataRecenzii {

    List<Recenzie> getAllRecenzii();
 Recenzie getRecenzieByIdRecenzie(int idRecenzie);
 void addRecenzie(Recenzie r);
}

The page class where i will display the list with reviews :

 package com.mycompany.licenta.pages;

import com.mycompany.licenta.data.IDataSource;
import com.mycompany.licenta.data.Hotel;
import com.mycompany.licenta.data.Hotel;
import com.mycompany.licenta.data.IDataSource;
import com.mycompany.licenta.datarecenzii.InterfataRecenzii;
import org.apache.tapestry5.annotations.Persist;
import org.apache.tapestry5.annotations.SessionState;
import com.mycompany.licenta.datarecenzii.Recenzie;
import java.util.List;

public class Details {
    @SessionState
    private IDataSource dataSource;
    private Hotel hotel;


    @SessionState
    private InterfataRecenzii dataSources;
    private Recenzie recenzie;

public void setHotel(Hotel c)
{
this.hotel = c;
}
public Hotel getHotel()
{
return hotel;
}
void onActivate(long id)
{
hotel = dataSource.getHotelById(id);
}


public List<Recenzie> getAllRecenzii()
{
    return dataSources.getAllRecenzii();
}


public Recenzie getRecenzie()
{
return recenzie;
} 
public void setRecenzie(Recenzie recenzie)
{
this.recenzie = recenzie;
}
}

The tml page component where it will be displayed

<t:grid t:source="allRecenzii" rowsPerPage="2" row="recenzie">
    </t:grid>

Answer 1

Your cannot @SessionState interfaces since tapestry will not know which implementing class to instantiate when reading the field from the session. Try replacing:

@SessionState
private InterfataRecenzii dataSources;

With:

@SessionState
private ListaRecenzii dataSources;

Also you can avoid the boilerplate of writing getRecenzi() and setRecenzii(Recenzii) in Details.java, just add @Property to the Recenzii field and the .tml will have access to it.