isCellEditable and Database doesn't work together

Question

My JTable doesn't refresh after I change a cell value. I can double click on a cell and change it's value but when I press OK or I click out of the cell the value's reset to the previous one, it's not update the table. Here's my code for my custom table model, I don't know how to update the database, because the table is taken from a db, when I change the cell's value.

package adisys.server.strumenti;

import java.sql.*;
import java.util.Formatter;

import javax.swing.event.TableModelEvent;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableModel;

import adisys.server.boundary.EditorPatologie;
import adisys.server.data.Database;
import adisys.server.data.Patologie;
import adisys.server.entity.Patologia;


/**
 * @author Francesco
 *
 */
public class ADISysTableModel extends AbstractTableModel implements TableModel {


    ResultSet dati;

    public ADISysTableModel(ResultSet nuoviDati)
    {
        dati=nuoviDati;

        try {
            //Trace
            System.out.println("- Creazione modello tabella: \""+ dati.getMetaData().getTableName(1) +"\"");
        } catch (SQLException e1) {
            e1.printStackTrace();
        }

    }

    @Override
    public int getColumnCount() {

        try {
            return dati.getMetaData().getColumnCount();
        } 
        catch (SQLException e) {
            e.printStackTrace();
            System.out.println("ERRORE: Calcolo del numero di colonne errato.");
            return 0;
        }
    }

    @Override
    public int getRowCount() {

        try {
            //Seleziona l'ultimo elemento
            dati.last();
            //Restituisce l'indice dell'elemento
            return (dati.getRow());


        } catch (SQLException e) {
            e.printStackTrace();
            System.out.println("ERRORE: Calcolo del numero di righe errato. (metodo getRowCount() )");
            return 0;
        }
    }

    @Override
    public Object getValueAt(int riga, int colonna) {

        try {
            //Sposta il cursore alla riga desiderata (con sfasamento di 1)
            dati.absolute(riga+1);

            //Estrae il valore nella colonna specificata e lo restituisce (con sfasamento di 1)
            return dati.getObject(colonna+1);

        } catch (SQLException e) {
            // In caso di errore restituisce un oggetto vuoto
            e.printStackTrace();

            //Trace
            System.out.println("ERRORE: Valore dell'elemento della tabella non valido.");
            return null;
        }
    }

    @Override
    public boolean isCellEditable(int rIndex, int cIndex)
    {
        return true;
    }


    @Override
    public String getColumnName(int col) {
        try {
            return dati.getMetaData().getColumnName(col+1);
        } catch (SQLException e) {
            // Eccezione
            e.printStackTrace();
            return "?";
        }
    }

    public Integer getID(int riga)
    {
        //Ricerca colonna ID
        for(int i=0; i<=getColumnCount(); i++)
            if(getColumnName(i).equals("ID"))
                return i;
        return null;
    }


    /**
     * Restituisce l'indice della colonna a partire dal nome della colonna ricercata
     * <b>N.B. L'indice della prima colonna è 0, l'ultimo è numeroColonne-1.</b>
     * @param Nome - Stringa con il nome della colonna
     * @return -1 se la colonna non e' stata trovata, altrimenti l'indice della colonna
     */
    public int getColumnIndex(String Nome)
    {
        for (int i=0; i<getColumnCount();i++)
            if( getColumnName(i)==Nome) return i;
        return -1;
    }


}

If you need something else, like the codes for the database or for the table editor just let me know ;) Thanks for your help :)

--EDIT-- Alright i've implemented the setValueAt method but when i click on the cell it gives me errors like this

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at adisys.server.strumenti.ADISysTableModel.setValueAt(ADISysTableModel.java:149)
    at javax.swing.JTable.setValueAt(Unknown Source)
    at javax.swing.JTable.editingStopped(Unknown Source)
    at javax.swing.AbstractCellEditor.fireEditingStopped(Unknown Source)
    at javax.swing.DefaultCellEditor$EditorDelegate.stopCellEditing(Unknown Source)
    at javax.swing.DefaultCellEditor.stopCellEditing(Unknown Source)
    at javax.swing.JTable$GenericEditor.stopCellEditing(Unknown Source)
    at javax.swing.DefaultCellEditor$EditorDelegate.actionPerformed(Unknown Source)
    at javax.swing.JTextField.fireActionPerformed(Unknown Source)
    at javax.swing.JTextField.postActionEvent(Unknown Source)
    at javax.swing.JTextField$NotifyAction.actionPerformed(Unknown Source)
    at javax.swing.SwingUtilities.notifyAction(Unknown Source)
    at javax.swing.JComponent.processKeyBinding(Unknown Source)
    at javax.swing.JComponent.processKeyBindings(Unknown Source)
    at javax.swing.JComponent.processKeyEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

my setValueAt method is this:

Vector<Paziente> content;

    @Override
    public void setValueAt(Object value, int rowIndex, int columnIndex)
    {
        Paziente row = this.content.elementAt(rowIndex);
        String strValue = (String)value;
        int IDValue = (int)value;
        if(columnIndex == 0)
        {
            row.setID(IDValue);
        }
        else if(columnIndex == 1)
        {
            row.setNome(strValue);
        }
        else if(columnIndex == 2)
        {
            row.setCognome(strValue);
        }
        fireTableCellUpdated(rowIndex, columnIndex);
    }

Would you please help me again on this? :) I'm getting crazy about this function, i know that for many is nothing difficult but for me it is... Thanks for answers, have a nice day! :D

UPDATE: i have solved this problem with this code: [CODE] @Override public void setValueAt(Object value, int rowIndex, int columnIndex) {String aValue = (String)value; String formatoIstruzione= "UPDATE PAZIENTI SET NOME = " + "'" + aValue + "'" + " WHERE ID = " + rowIndex + ";"; Database.esegui(formatoIstruzione.toUpperCase()); Pianificatore.aggiornaTabelle(); } } [/CODE]

In other words i launch the sql instruction to update the table and then i refresh it's view so it's almost show the new value. Thank you everybody for the help and the inspiration you gave me, we've got it, finally!! *_*

Answer 1

I don't see any implementation for setValueAt() in your TableModel. How can you expect either of those things to happen without it? Try implementing that method and see if you do better.

Update:

You have a null reference at line 149 in ADISysTableModel:

at adisys.server.strumenti.ADISysTableModel.setValueAt(ADISysTableModel.java:149)

Open a text editor, go to that line number, and inspect the object references. Run in a debugger to see which one is null. It'll be easy to fix.

See this line?

Vector<Paziente> content;

That sets the reference to null because you didn't call new to set it to a new reference.

Change it to this and the NPE goes away:

Vector<Paziente> content = new Vector<Paziente>();

This might not be what you want, but it won't be null.

I think you should be dealing with the underlying table model, not this random vector. You know your code, but I don't think this is going to make you happy, either.

I'd strongly urge you to simplify things and go through a JTable tutorial before you attempt your real problem:

http://docs.oracle.com/javase/tutorial/uiswing/components/table.html