SWT Jface Eclipse Java

/*
SWT/JFace in Action
GUI Design with Eclipse 3.0
Matthew Scarpino, Stephen Holder, Stanford Ng, and Laurent Mihalkovic
ISBN: 1932394273
Publisher: Manning
*/
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
public class UsernamePasswordDialog extends Dialog {
  private static final int RESET_ID = IDialogConstants.NO_TO_ALL_ID + 1;
  private Text usernameField;
  private Text passwordField;
  public UsernamePasswordDialog(Shell parentShell) {
    super(parentShell);
  }
  protected Control createDialogArea(Composite parent) {
    Composite comp = (Composite) super.createDialogArea(parent);
    GridLayout layout = (GridLayout) comp.getLayout();
    layout.numColumns = 2;
    Label usernameLabel = new Label(comp, SWT.RIGHT);
    usernameLabel.setText("Username: ");
    usernameField = new Text(comp, SWT.SINGLE);
    GridData data = new GridData(GridData.FILL_HORIZONTAL);
    usernameField.setLayoutData(data);
    Label passwordLabel = new Label(comp, SWT.RIGHT);
    passwordLabel.setText("Password: ");
    passwordField = new Text(comp, SWT.SINGLE | SWT.PASSWORD);
    data = new GridData(GridData.FILL_HORIZONTAL);
    passwordField.setLayoutData(data);
    return comp;
  }
  protected void createButtonsForButtonBar(Composite parent) {
    super.createButtonsForButtonBar(parent);
    createButton(parent, RESET_ID, "Reset All", false);
  }
  protected void buttonPressed(int buttonId) {
    if (buttonId == RESET_ID) {
      usernameField.setText("");
      passwordField.setText("");
    } else {
      super.buttonPressed(buttonId);
    }
  }
}