Connection Troubles

[Amy Phillips]

I am trying to get my database connection sorted out - i can create the conenction and all works fine but I will need to connect to the databse from a number of files and don't want to have to keep copying the code so I am trying to move my connection code into a class and have the other classes call it - not sure if this will technically work. Would it be easier to go with a connection pool?
Anyway this is what I ahve so far - both parts sort of work but i can't get them to talk to each other
Connection Code

 
import java.sql.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class Connect
{
    private Connection connection;
    public Connect()
    {
       String url = "jdbc :-o	 dbc:Boris";

try
{
    Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
    connection = DriverManager.getConnection(url, "", "");
}
catch( ClassNotFoundException cnfex )
{
System.err.println("Failed to load the JDBC/ODBC driver");
cnfex.printStackTrace();
System.exit(1);
}
catch ( SQLException sqlex )
{
System.err.println("Unable to connect");
sqlex.printStackTrace();
}
return connection;
    }
    public void shutDown()
    {
    try
    {
    connection.close();
    }
    catch (SQLException sqlex)
    {
    System.err.println("Unable to disconnect");
    sqlex.printStackTrace();
    }
    }
} 

Query Code

 
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()
    {
    connection = Connect.Connect();
    getTable();
    setSize (450, 150);
    show();
    }
    
    public void getTable()
    {
    Statement statement;
    ResultSet resultSet;
    
    try 
    {
    String query = "Select * FROM Project";
    statement = connection.createStatement();
    resultSet = statement.executeQuery( query );
    displayResultSet( resultSet );
    statement.close();
    }
    catch (SQLException sqlex )
    {
    sqlex.printStackTrace();
    }
    }
    
    private void displayResultSet( ResultSet rs ) throws SQLException
    {
    boolean moreRecords = rs.next();
    
    if (! moreRecords)
    {
    JOptionPane.showMessageDialog( this, "ResultSet contained no records");
    setTitle("No records found");
    return;
    }
    
    setTitle( "Project");
    
    Vector columnHeads = new Vector();
    Vector rows = new Vector();
    
    try
    {
    ResultSetMetaData rsmd = rs.getMetaData();
    
    for(int i = 1; i <= rsmd.getColumnCount(); ++i)
    {
    columnHeads.addElement( rsmd.getColumnName( i ));
    }
    
    do {
    rows.addElement( getNextRow( rs, rsmd ));
    } while (rs.next() );
    
    JTable table = new JTable( rows, columnHeads);
    JScrollPane scroller = new JScrollPane( table );
    getContentPane().add( scroller, BorderLayout.CENTER );
    validate();
    
    }
    catch( SQLException sqlex )
    {
    sqlex.printStackTrace();
    }
    }
    
    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;
    }
    
    
    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 );
    }
    }
    );
    }
}
 

Any tips would be very welcome
Thanks

[Bosun Bello]

In what seems to be the constructor for the Connect class, you are doing this: return connection
First of all, a constructor should not be returning a value bacause it implicitly returns a reference "this" to the class.
In your TableDisplay class, this Connect.Connect(); is actually a method call. Bottom line is you should be returning the collection object from within a method. And all this compiled?

[Amy Phillips]

Hi,
Thanks for your pointers, I now understand why it doesn't work but am a bit unclear as to how to get it working. Firstly should I be creating this connection class at all? secondly what do I do to the connection class to allow the other classes to request and receive a connection
Thanks

[Amy Phillips]

Ahhh have finally realised where its all going wrong. I think i am approaching this problem from the wrong direction! Thanks for all your help