/**
* Method withButtonPanel.
* @return WindowBuilder
*/
public WindowBuilder withButtonPanel() {
final IButton enterButton = this.createEnterButton();
final IButton clearButton = this.createClearButton();
final IButton exitButton = this.createExitButton();
final ILayout layout = new DefaultLayout();
layout.defaultSettings();
layout.getConstraints().weighty = 0;
final JPanel swingButtonPanel = new JPanel(layout.getLayout());
final IPanel panel = new CommandButtonPanel(swingButtonPanel, layout, enterButton, clearButton, exitButton);