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

public class ScalarJ extends JFrame
                     implements ActionListener,
                                WindowListener
{
  Connection con = null;
  DatabaseMetaData dbmd;
  DefaultComboBoxModel dcbm = 
     new DefaultComboBoxModel();

  JButton         jbConnect = new JButton("Connect"),
                  jbFN = new JButton( 
                    "Get Functions" ),
                  jbDoFn = new JButton( 
                    "Get CURDATE" );
  JComboBox       jcb = new JComboBox( dcbm );
  JLabel          jlUserID = new JLabel("UserID:"),
                  jlPassword = new JLabel(
                    "Password:");
  JPanel          jpCenter = new JPanel( 
                     new BorderLayout() ),
                  jpCenterEast = new JPanel(),
                  jpCenterWest = new JPanel( 
                     new BorderLayout() ),
                  jpCenterWestNorth = new JPanel( 
                     new GridLayout( 3,2 ) ),
                  jpCenterWestSouth = new JPanel( 
                     new GridLayout( 2,1 ) ),
                  jpNorth = new JPanel( 
                     new BorderLayout() ),
                  jpNorthNorth = new JPanel(),
                  jpNorthSouth = new JPanel();
  JPasswordField  jpfPassword = 
                     new JPasswordField( 10 );
  JRadioButton    jrbNumeric = new JRadioButton( 
                    "Numeric" ),
                  jrbString = new JRadioButton( 
                    "String" ),
                  jrbTD = new JRadioButton( 
                    "Date/Time" ),
                  jrbSystem = new JRadioButton( 
                    "System" );
  JTextArea       jta = new JTextArea( 
                    "Errors show here.", 4, 30 );
  JTextField      jtUserID = new JTextField( 10 );

  ResultSet rs = null;
  Statement stmt = null;
  ResourceBundle rbConnect;
  String sDriver,
         sDriverKey = "CSDriver",
         sPassword,
         srbName = "ConnectJ",
         sURL,
         sURLKey="CSURL",
         sUserID;


  public ScalarJ()
  {
    super("ScalarJ");

    try  // get the PropertyResourceBundle
    {
      rbConnect = ResourceBundle.getBundle( srbName );

      sDriver   = rbConnect.getString( sDriverKey );
      sURL      = rbConnect.getString( sURLKey );
    }
    catch( MissingResourceException mre )
    {
      System.err.println(
                 "ResourceBundle problem for " + 
                  srbName + ", program ends." );
      System.err.println("Specific error: " + 
                          mre.getMessage() );
      endApp(); // exit on error
    }

    jbConnect.addActionListener( this );
    jbDoFn.addActionListener( this );
    jbFN.addActionListener( this );
 
    jrbTD.setSelected( true );
    ButtonGroup bg = new ButtonGroup();
    bg.add( jrbNumeric );
    bg.add( jrbString );
    bg.add( jrbTD );
    bg.add( jrbSystem );

    jpCenterWestNorth.add( jrbNumeric );
    jpCenterWestNorth.add( jrbString );
    jpCenterWestNorth.add( jrbTD );
    jpCenterWestNorth.add( jrbSystem );


    jbFN.setEnabled( false );
    jbDoFn.setEnabled( false );
    jpCenterWestSouth.add( jbFN );
    jpCenterWestSouth.add( jbDoFn );

    jpCenterWest.add( jpCenterWestNorth, 
       BorderLayout.NORTH );
    jpCenterWest.add( jpCenterWestSouth, 
       BorderLayout.SOUTH );

    jcb.setMaximumRowCount( 5 );
    jpCenterEast.add( jcb );
    jpCenter.add( jpCenterWest, BorderLayout.WEST );
    jpCenter.add( jpCenterEast, BorderLayout.EAST );


    jpNorthNorth.add( jlUserID );
    jpNorthNorth.add( jtUserID );
    jpNorthNorth.add( jlPassword );
    jpNorthNorth.add( jpfPassword );

    jpNorthSouth.add( jbConnect );

    JScrollPane jsp = new JScrollPane( jta );
    jpNorthSouth.add( jsp );

    jpNorth.add( jpNorthNorth, BorderLayout.NORTH );
    jpNorth.add( jpNorthSouth, BorderLayout.SOUTH );

    Container cp = getContentPane();
    cp.add( jpNorth,  BorderLayout.NORTH );
    cp.add( jpCenter, BorderLayout.CENTER );

    addWindowListener( this );
    pack();
    show();

  } // end constructor


  public void doConnect()
  {
    try // Attempt to load the JDBC driver 
    {   // with newInstance
        Class.forName( sDriver ).newInstance();
    }
    catch( Exception e )  // error
    {
      jta.setText("Failed to load current driver.");
      return;
    } // end catch

    try
    {
      con = DriverManager.getConnection ( sURL,
                                          sUserID,
                                          sPassword);
      stmt = con.createStatement();

// insert code to get DatabaseMetaData


// end insert


      jbConnect.setEnabled( false );

      LoadFunctions();
      jbFN.setEnabled( true );
    }
    catch ( SQLException SQLe)
    {
      reportSQLError( SQLe,
        "problems in DoConnect():" );

      if( con != null )
      {
        try { con.close(); }
        catch( Exception e ) {}
        stmt = null;
      }

      return;
    } // end catch
  } // end doConnect


  public void doInvokeFn()
  {
    String sTemp1 = null,
           sTemp2 = null,
           sTemp3 = null;

    if( jrbNumeric.isSelected() )
    {
      sTemp1 = "PI is: ";
      sTemp2 = "PI()";
    }
    else
    if( jrbString.isSelected() )
    {
      sTemp1 = "LTRIM result is: ";
      sTemp2 = "LTRIM('     Right')";
    }
    else
    if( jrbTD.isSelected() )
    {
      sTemp1 = "CURDATE is: ";
      sTemp2 = "CURDATE()";
    }
    else
    if( jrbSystem.isSelected() )
    {
      sTemp1 = "USER is: ";
      sTemp2 = "USER()";
    }

    try
    { 

// insert code execute the query, including
// scalar syntax, get the returned value
// and close the ResultSet


// end insert


      jta.setText( sTemp1 + sTemp3 );
      
    } // end try
    catch ( SQLException SQLe)
    {
      reportSQLError( SQLe,
        "problems in doInvokeFn():" );
      SQLe.printStackTrace();
    }
  } // end doInvokeFn


  public void LoadFunctions()
  {
    String sFunctions = null;
    StringTokenizer st = null;

    dcbm.removeAllElements();
    try
    { 

// insert code to get avalable scalar functions
// for the current selection

// end insert


      jbDoFn.setEnabled( false );
      if( sFunctions.equals( "" ) )
      {
        dcbm.addElement( "None Returned." );
        return;
      }
      else
      {

// insert code to get each function name
// from the returned String

// end insert

      }

      if( jrbNumeric.isSelected() )
      {
        jbDoFn.setText( "Get PI" );
        if( dcbm.getIndexOf( "PI" ) >= 0 )
        {
          jbDoFn.setEnabled( true );
        }
      }

      if( jrbString.isSelected() )
      {
        jbDoFn.setText( "Get LTRIM" );
        if( dcbm.getIndexOf( "LTRIM" ) >= 0 )
        {
          jbDoFn.setEnabled( true );
        }
      }

      if( jrbTD.isSelected() )
      {
        jbDoFn.setText( "Get CURDATE" );
        if( dcbm.getIndexOf( "CURDATE" ) >= 0 )
        {
          jbDoFn.setEnabled( true );
        }
      }

      if( jrbSystem.isSelected() )
      {
        jbDoFn.setText( "Get USER" );
        if( dcbm.getIndexOf( "USER" ) >= 0 )
        {
          jbDoFn.setEnabled( true );
        }
      }
    } // end try
    catch ( SQLException SQLe)
    {
      reportSQLError( SQLe,
        "problems in doInvokeFn():" );
      SQLe.printStackTrace();
    }
  } // end LoadFunctions


  public void endApp()
  {
    if( stmt != null)
    {
      try { stmt.close(); }
      catch( Exception e ) {}
    }

    if( con != null)
    {
      try { con.close(); }
      catch( Exception e ) {}
    }

    dispose();
    System.exit(0);
  } // end endApp


  // ActionListener implementation
  public void actionPerformed(ActionEvent e)
  {
    Object oSource = e.getSource();

    jta.setText( "No Errors." );
    if( oSource == jbDoFn )
    {
      doInvokeFn();
      return;
    }

    if( oSource == jbFN )
    {
      LoadFunctions();
      return;
    }

    if( oSource == jbConnect )
    {
      sUserID = jtUserID.getText();
      sPassword = jpfPassword.getText();
      doConnect();
      return;
    }

  } // end actionPerformed


  public void reportSQLError( SQLException SQLe,
                              String       s )
  {
      jta.setText( s + "\n" );
      jta.append( SQLe.getMessage() + "\n" );
      jta.append( "SQL State: " +
         SQLe.getSQLState() + "\n"  );
  } // end reportSQLError


// Window Listener Implementation
    public void windowOpened(WindowEvent e) {}

     public void windowClosing(WindowEvent e) 
     { 
       endApp();
     }

    public void windowClosed(WindowEvent e) {}
    public void windowIconified(WindowEvent e) {}
    public void windowDeiconified(WindowEvent e) {}
    public void windowActivated(WindowEvent e) {}
    public void windowDeactivated(WindowEvent e) {}
// End Window Listener Implementation

  public static void main (String args[])
  {
    new ScalarJ();
  } // end main

} // end class ScalarJ