# QueryViewer.java An interactive database query viewer. Connects to the specified Oracle or Sybase database, executes a query, and presents the results in a JTable. Uses the following file:
* DBResultsTableModel.java Simple class that tells a JTable how to extract relevant data from a DBResults object (which is used to store the results from a database query).
############################################################################
package cwp;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
/** An interactive database query viewer. Connects to
* the specified Oracle or Sybase database, executes a query,
* and presents the results in a JTable.
*
*/
public class QueryViewer extends JFrame
implements ActionListener{
public static void main(String[] args) {
new QueryViewer();
}
private JTextField hostField, dbNameField,
queryField, usernameField;
private JRadioButton oracleButton, sybaseButton;
private JPasswordField passwordField;
private JButton showResultsButton;
Container contentPane;
private JPanel tablePanel;
public QueryViewer () {
super("Database Query Viewer");
WindowUtilities.setNativeLookAndFeel();
addWindowListener(new ExitListener());
contentPane = getContentPane();
contentPane.add(makeControlPanel(), BorderLayout.NORTH);
pack();
setVisible(true);
}
/** When the "Show Results" button is pressed or
* RETURN is hit while the query textfield has the
* keyboard focus, a database lookup is performed,
* the results are placed in a JTable, and the window
* is resized to accommodate the table.
*/
public void actionPerformed(ActionEvent event) {
String host = hostField.getText();
String dbName = dbNameField.getText();
String username = usernameField.getText();
String password =
String.valueOf(passwordField.getPassword());
String query = queryField.getText();
int vendor;
if (oracleButton.isSelected()) {
vendor = DriverUtilities.ORACLE;
} else {
vendor = DriverUtilities.SYBASE;
}
if (tablePanel != null) {
contentPane.remove(tablePanel);
}
tablePanel = makeTablePanel(host, dbName, vendor,
username, password,
query);
contentPane.add(tablePanel, BorderLayout.CENTER);
pack();
}
// Executes a query and places the result in a
// JTable that is, in turn, inside a JPanel.
private JPanel makeTablePanel(String host,
String dbName,
int vendor,
String username,
String password,
String query) {
String driver = DriverUtilities.getDriver(vendor);
String url = DriverUtilities.makeURL(host, dbName, vendor);
DBResults results =
DatabaseUtilities.getQueryResults(driver, url,
username, password,
query, true);
JPanel panel = new JPanel(new BorderLayout());
if (results == null) {
panel.add(makeErrorLabel());
return(panel);
}
DBResultsTableModel model =
new DBResultsTableModel(results);
JTable table = new JTable(model);
table.setFont(new Font("Serif", Font.PLAIN, 17));
table.setRowHeight(28);
JTableHeader header = table.getTableHeader();
header.setFont(new Font("SansSerif", Font.BOLD, 13));
panel.add(table, BorderLayout.CENTER);
panel.add(header, BorderLayout.NORTH);
panel.setBorder
(BorderFactory.createTitledBorder("Query Results"));
return(panel);
}
// The panel that contains the textfields, checkboxes,
// and button.
private JPanel makeControlPanel() {
JPanel panel = new JPanel(new GridLayout(0, 1));
panel.add(makeHostPanel());
panel.add(makeUsernamePanel());
panel.add(makeQueryPanel());
panel.add(makeButtonPanel());
panel.setBorder
(BorderFactory.createTitledBorder("Query Data"));
return(panel);
}
// The panel that has the host and db name textfield and
// the driver radio buttons. Placed in control panel.
private JPanel makeHostPanel() {
JPanel panel = new JPanel();
panel.add(new JLabel("Host:"));
hostField = new JTextField(15);
panel.add(hostField);
panel.add(new JLabel(" DB Name:"));
dbNameField = new JTextField(15);
panel.add(dbNameField);
panel.add(new JLabel(" Driver:"));
ButtonGroup vendorGroup = new ButtonGroup();
oracleButton = new JRadioButton("Oracle", true);
vendorGroup.add(oracleButton);
panel.add(oracleButton);
sybaseButton = new JRadioButton("Sybase");
vendorGroup.add(sybaseButton);
panel.add(sybaseButton);
return(panel);
}
// The panel that has the username and password textfields.
// Placed in control panel.
private JPanel makeUsernamePanel() {
JPanel panel = new JPanel();
usernameField = new JTextField(10);
passwordField = new JPasswordField(10);
panel.add(new JLabel("Username: "));
panel.add(usernameField);
panel.add(new JLabel(" Password:"));
panel.add(passwordField);
return(panel);
}
// The panel that has textfield for entering queries.
// Placed in control panel.
private JPanel makeQueryPanel() {
JPanel panel = new JPanel();
queryField = new JTextField(40);
queryField.addActionListener(this);
panel.add(new JLabel("Query:"));
panel.add(queryField);
return(panel);
}
// The panel that has the "Show Results" button.
// Placed in control panel.
private JPanel makeButtonPanel() {
JPanel panel = new JPanel();
showResultsButton = new JButton("Show Results");
showResultsButton.addActionListener(this);
panel.add(showResultsButton);
return(panel);
}
// Shows warning when bad query sent.
private JLabel makeErrorLabel() {
JLabel label = new JLabel("No Results", JLabel.CENTER);
label.setFont(new Font("Serif", Font.BOLD, 36));
return(label);
}
}
Aug 06