// Fig. 23.30: DisplayQueryResults.java
// Display the contents of the Authors table in the
// Books database.

import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

public class DisplayQueryResults extends JFrame {
   
   // JDBC driver and database URL
   static final String JDBC_DRIVER = "com.ibm.db2j.jdbc.DB2jDriver";
   static final String DATABASE_URL = "jdbc:db2j:books";
   
   // default query retrieves all data from authors table
   static final String DEFAULT_QUERY = "SELECT * FROM authors";
   
   private ResultSetTableModel tableModel;
   private JTextArea queryArea;
   
   // create ResultSetTableModel and GUI
   public DisplayQueryResults() 
   {   
      super( "Displaying Query Results" );
         
      // create ResultSetTableModel and display database table
      try {

         // specify location of database on filesystem
         System.setProperty( "db2j.system.home", "C:/Cloudscape_5.0" );

         // create TableModel for results of query SELECT * FROM authors
         tableModel = new ResultSetTableModel( JDBC_DRIVER, DATABASE_URL, 
            DEFAULT_QUERY );

         // set up JTextArea in which user types queries
         queryArea = new JTextArea( DEFAULT_QUERY, 3, 100 );
         queryArea.setWrapStyleWord( true );
         queryArea.setLineWrap( true );
         
         JScrollPane scrollPane = new JScrollPane( queryArea,
            ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, 
            ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER );
         
         // set up JButton for submitting queries
         JButton submitButton = new JButton( "Submit Query" );

         // create Box to manage placement of queryArea and 
         // submitButton in GUI
         Box box = Box.createHorizontalBox();
         box.add( scrollPane );
         box.add( submitButton );

         // create JTable delegate for tableModel 
         JTable resultTable = new JTable( tableModel );
         
         // place GUI components on content pane
         Container c = getContentPane();         
         c.add( box, BorderLayout.NORTH );
         c.add( new JScrollPane( resultTable ), BorderLayout.CENTER );

         // create event listener for submitButton
         submitButton.addActionListener( 
         
            new ActionListener() {
         
               // pass query to table model
               public void actionPerformed( ActionEvent event )
               {
                  // perform a new query
                  try {
                     tableModel.setQuery( queryArea.getText() );
                  }
                  
                  // catch SQLExceptions when performing a new query
                  catch ( SQLException sqlException ) {
                     JOptionPane.showMessageDialog( null, 
                        sqlException.getMessage(), "Database error", 
                        JOptionPane.ERROR_MESSAGE );
                     
                     // try to recover from invalid user query 
                     // by executing default query
                     try {
                        tableModel.setQuery( DEFAULT_QUERY );
                        queryArea.setText( DEFAULT_QUERY );
                     }
                     
                     // catch SQLException when performing default query
                     catch ( SQLException sqlException2 ) {
                        JOptionPane.showMessageDialog( null, 
                           sqlException2.getMessage(), "Database error", 
                           JOptionPane.ERROR_MESSAGE );
         
                        // ensure database connection is closed
                        tableModel.disconnectFromDatabase();
         
                        System.exit( 1 );   // terminate application
                        
                     }  // end inner catch                   
             
                  } // end outer catch
                  
               }  // end actionPerformed
               
            }  // end ActionListener inner class          
            
         ); // end call to addActionListener

         // set window size and display window
         setSize( 500, 250 );
         setVisible( true );   
         
      }  // end try

      // catch ClassNotFoundException thrown by 
      // ResultSetTableModel if database driver not found
      catch ( ClassNotFoundException classNotFound ) {
         JOptionPane.showMessageDialog( null, 
            "Cloudscape driver not found", "Driver not found",
            JOptionPane.ERROR_MESSAGE );
         
         System.exit( 1 );   // terminate application
      }
      
      // catch SQLException thrown by ResultSetTableModel 
      // if problems occur while setting up database
      // connection and querying database
      catch ( SQLException sqlException ) {
         JOptionPane.showMessageDialog( null, sqlException.getMessage(), 
            "Database error", JOptionPane.ERROR_MESSAGE );
         
         // ensure database connection is closed
         tableModel.disconnectFromDatabase();
         
         System.exit( 1 );   // terminate application
      }
      
      // dispose of window when user quits application (this overrides
      // the default of HIDE_ON_CLOSE)
      setDefaultCloseOperation( DISPOSE_ON_CLOSE );
      
      // ensure database connection is closed when user quits application
      addWindowListener(
      
         new WindowAdapter() {
            
            // disconnect from database and exit when window has closed
            public void windowClosed( WindowEvent event )
            {
               tableModel.disconnectFromDatabase();
               System.exit( 0 );
            }
         }
      );      
      
   }  // end DisplayQueryResults constructor
   
   // execute application
   public static void main( String args[] ) 
   {
      new DisplayQueryResults();     
   }
   
}  // end class DisplayQueryResults



/**************************************************************************
 * (C) Copyright 1992-2003 by Deitel & Associates, Inc. and               *
 * Prentice Hall. All Rights Reserved.                                    *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 *************************************************************************/