/*
 * This sample applet just selects 'Hello World' and the date from the database
 */

// Import the JDBC classes
import java.sql.*;

// Import the java classes used in applets
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;

public class JdbcApplet extends java.applet.Applet
{
  // The driver to load
  static final String driver_class = "oracle.jdbc.driver.OracleDriver";

  // The connect string 
  static final String connect_string = 
                  "jdbc:oracle:thin:scott/tiger@amber:1521:orcl";

  // The query we will execute
  static String query = "select 'Hello JDBC: ' || sysdate from dual";
  

  // The button to push for executing the query
  Button execute_button;

  // The place to obtain a new query.
  TextField queryInput;

  // The place where to dump the query result
  TextArea output;

  // The connection to the database
  Connection conn;

  // Create the User Interface
  public void init ()
  {
    connect_string = getParameter("CONNECT");
    this.setLayout (new BorderLayout ());
    Panel p = new Panel ();
    p.setLayout (new FlowLayout (FlowLayout.LEFT));
    execute_button = new Button ("Execute");
    p.add (execute_button);
    this.add ("South", p);
    output = new TextArea (10, 60);
    this.add ("Center", output);
    queryInput = new TextField( query ) ;
    this.add("North", queryInput);
  }

  // Do the work
  public boolean action (Event ev, Object arg)
  {
    if (ev.target == execute_button)
    {
      try
      {
        // Clear the output area
        output.setText ("");

        // See if we need to open the connection to the database
        if (conn == null)
        {
          // Load the JDBC driver
          output.appendText ("Loading JDBC driver " + driver_class + "\n");
          Class.forName (driver_class);

          // Connect to the databse
          output.appendText ("Connecting to " + connect_string + "\n");
          conn = DriverManager.getConnection (connect_string);
          output.appendText ("Connected\n");
        }

        // Create a statement
        Statement stmt = conn.createStatement ();

        // Execute the query
        if (queryInput.getText().length() > 0) {
          query = queryInput.getText();
          output.appendText ("Executing query " + query + "\n");
          ResultSet rset = stmt.executeQuery (query);

          // Dump the result
          displayResults(rset);
        } else {
          output.appendText("no query to execute\n");
        }

        // We're done
        output.appendText ("done.\n");
      }
      catch (Exception e)
      {
        // Oops
        output.appendText (e.getMessage () + "\n"); 
        e.printStackTrace();
      }
      return true;
    }
    else
      return false;
  }

  private void displayResults(ResultSet rs) throws SQLException {
    ResultSetMetaData meta = rs.getMetaData();
    int numcols = meta.getColumnCount();
    
    int numrows = 0;
    
    Panel disp = new Panel();

    output.appendText ("Identifying columns.\n");

    for(int i = 1; i <= numcols; i++) {
       disp.add(new Label(meta.getColumnLabel(i)));
    }
    
    output.appendText ("Building rows.\n");

    boolean more = rs.next();
    while (more) {
       for (int i=1; i <= numcols; i++) {
          disp.add(new TextField(rs.getString(i)));
       }
       output.appendText ("+");
       numrows ++;
       more = rs.next();
    }
    disp.setLayout( new GridLayout(numrows+1, numcols));
  
    output.appendText ("\nBuilding Window\n");
    Frame dlg = new Frame("Results");
    dlg.addWindowListener( new WindowCloser(dlg) ); 
    dlg.add(disp);
    dlg.setBackground( Color.white );
    dlg.setSize( (numrows+1) * 25, numcols * 75);
    dlg.show();
  }

}
class WindowCloser extends WindowAdapter {
  private Window adaptee;

  public WindowCloser(Window target) { adaptee = target; }
  public void windowClosing(WindowEvent we) { adaptee.dispose(); }
}