Clase de ejemplo utilizando SwingWorker

Codigo de la Clase de Ejemplo

Esto complementa al tutorial Uso de swingworker en una aplicacion

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * FrmProductos.java
 *
 * Created on 18-oct-2010, 14:14:27
 */
package miaplicacion.ui;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import miaplicacion.util.ArraylistTableModel;

/**
 *
 * @author dinfantas
 */
public class FrmProductos extends javax.swing.JInternalFrame {

    private java.sql.Connection con;

    /** Creates new form FrmProductos */
    public FrmProductos() {
        initComponents();
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // 
    private void initComponents() {

        jbtnListar = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        jtblProductos = new javax.swing.JTable();
        progressBar = new javax.swing.JProgressBar();

        setClosable(true);
        setIconifiable(true);
        setMaximizable(true);
        setTitle("Productos");

        jbtnListar.setText("Listar");
        jbtnListar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jbtnListarActionPerformed(evt);
            }
        });

        jtblProductos.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null}
            },
            new String [] {
                "Title 1", "Title 2", "Title 3", "Title 4"
            }
        ));
        jScrollPane1.setViewportView(jtblProductos);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                        .addComponent(jbtnListar)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 435, Short.MAX_VALUE))
                    .addComponent(progressBar, javax.swing.GroupLayout.DEFAULT_SIZE, 435, Short.MAX_VALUE))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jbtnListar)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 282, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(progressBar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// 

    private void jbtnListarActionPerformed(java.awt.event.ActionEvent evt) {

        //iniciamos nuestra barra de progreso
        progressBar.setValue(0);
        
        //Definimos nuestro Query
        final String query = "select * from APP.PRODUCT";
        //vamos a crear nuestra conexion a la BD
        conectar();


        final javax.swing.SwingWorker worker = new javax.swing.SwingWorker() {

            //donde almacenaremos los datos
            ArraylistTableModel model;
            ArrayList datos;
            String[] cols = new String[8];//son 8 columnas

            @Override
            protected Void doInBackground() throws Exception {
                datos = new ArrayList();//instanciamos                
                try {
                    //Creamos un Statement para ejecutar el query                    
                    java.sql.PreparedStatement pstmt = con.prepareStatement(query);
                    //ejecutamos el query                     
                    pstmt.executeQuery();
                    // asignamos el resutaldo a rs
                    java.sql.ResultSet rs = pstmt.getResultSet();
                    //asignamos la metadata
                    java.sql.ResultSetMetaData rm = rs.getMetaData();
                    //creamos un array donde pondremos los nombres de columnas
                    for (int i = 0; i < rm.getColumnCount(); i++) {
                        cols[i] = rm.getColumnName(i+1).toString();
                    }
                    //recorremos el Resultset
                    while (rs.next()) {//mientras halla datos
                        ArrayList fila = new ArrayList();//instanciamos donde almacenaremos los datos de cada fila
                        for (int i = 1; i <= rm.getColumnCount(); i++) {
                            fila.add(rs.getObject(i).toString());
                        }                        
                        datos.add(fila);//agregamos la fila cargada
                        setProgress(datos.size());//actualizamos el progreso
                    }                   

                } catch (SQLException ex) {
                    Logger.getLogger(FrmProductos.class.getName()).log(Level.SEVERE, null, ex);                    
                }

                return null;
            }

            @Override
            protected void done() {
                setProgress(100);
                jtblProductos.setModel(new ArraylistTableModel(datos, cols));
            }
        };

        worker.addPropertyChangeListener(new PropertyChangeListener() {//agregarmos un escuchador de cambio de propiedad

            public void propertyChange(PropertyChangeEvent pce) {
                progressBar.setValue(worker.getProgress());//actualizamos el valor del progressBar
            }
        });

        worker.execute();
    }
    // Variables declaration - do not modify
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JButton jbtnListar;
    private javax.swing.JTable jtblProductos;
    private javax.swing.JProgressBar progressBar;
    // End of variables declaration

    private void conectar() {
        try {
            Class.forName("org.apache.derby.jdbc.ClientDriver").newInstance();
            String dbUrl = "jdbc:derby://localhost:1527/sample";//URL DE CONEXION A LA DB            
            con = DriverManager.getConnection(dbUrl,"app","app");
        } catch (InstantiationException ex) {
            Logger.getLogger(FrmProductos.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            Logger.getLogger(FrmProductos.class.getName()).log(Level.SEVERE, null, ex);
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(FrmProductos.class.getName()).log(Level.SEVERE, null, ex);
        } catch (SQLException ex) {
            Logger.getLogger(FrmProductos.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}