// TableDisplay.java
// This program displays the contents of the Authors table
// in the Books database.

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

public class TableDisplay extends JFrame 
{
  private Connection connection;
  private JTable table;
    
    
  public TableDisplay() 
  {   
    // The URL specifying the Books database to which 
    // this program connects using JDBC to connect to a
    // Microsoft ODBC database.
    String url = "jdbc:odbc:Books";  
    String username = "anonymous";
    String password = "guest";

    // Load the driver to allow connection to the database
    try {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
      connection = DriverManager.getConnection(url, username, password );
    } 
    catch (ClassNotFoundException cnfex) {
      System.err.println("Failed to load JDBC/ODBC driver." );
      cnfex.printStackTrace();
      System.exit(1);  // terminate program
    }
    catch (SQLException sqlex) {
      System.err.println( "Unable to connect" );
      sqlex.printStackTrace();
    }

    getTable();
    setSize(450, 150);
    setVisible(true);
  }  // end of TableDisplay()
   

  private void getTable()
  {
    Statement statement;
    ResultSet resultSet;
      
    try {
      String query = "SELECT * FROM Authors";
      statement = connection.createStatement();
      resultSet = statement.executeQuery( query );
      displayResultSet( resultSet );
      statement.close();
    }
    catch ( SQLException sqlex ) {
      sqlex.printStackTrace();
    }
   }  // end of getTable()
   

   private void displayResultSet(ResultSet rs) throws SQLException
   {
    // position to first record
    boolean moreRecords = rs.next();  

    // If there are no records, display a message
    if (!moreRecords) {
      JOptionPane.showMessageDialog( this, "ResultSet contained no records" );
      setTitle( "No records to display" );
      return;
    }

    setTitle( "Authors table from Books" );
    Vector<String> columnHeads = new Vector<String>();
    Vector rows = new Vector();
    try {
      // get column heads
      ResultSetMetaData rsmd = rs.getMetaData();
      
      for ( int i = 1; i <= rsmd.getColumnCount(); ++i) 
        columnHeads.addElement( rsmd.getColumnName(i));

      // get row data
      do {
        rows.addElement( getNextRow( rs, rsmd ) ); 
      } while (rs.next());

      // display table with ResultSet contents
      table = new JTable( rows, columnHeads );
      JScrollPane scroller = new JScrollPane( table );
      getContentPane().add(scroller, BorderLayout.CENTER );
      validate();
    }
    catch ( SQLException sqlex ) {
      sqlex.printStackTrace();
    }
  }  // end of displayResultSet()
  

   private Vector getNextRow( ResultSet rs, 
                              ResultSetMetaData rsmd ) throws SQLException
   {
      Vector currentRow = new Vector();
      for (int i = 1; i <= rsmd.getColumnCount(); ++i)
         switch( rsmd.getColumnType( i ) ) {
            case Types.VARCHAR:
                  currentRow.addElement( rs.getString(i) );
               break;
            case Types.INTEGER:
                  currentRow.addElement( 
                     new Long( rs.getLong( i ) ) );
               break;
            default: 
               System.out.println( "Type was: " + 
                  rsmd.getColumnTypeName( i ) );
         }
      
      return currentRow;
   }  // end of getNextRow()


  public void shutDown()
  {
    try {
      connection.close();
    }
    catch ( SQLException sqlex ) {
      System.err.println( "Unable to disconnect" );
      sqlex.printStackTrace();
    }
  }  // end of shutDown()


// ------------------------------------------------------

   public static void main( String args[] ) 
   {
      final TableDisplay app = new TableDisplay();
      app.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) 
        { app.shutDown();
          System.exit(0);
        }
      });
   }  // end of main()
   
}  // end of TableDisplay class