public ConfigurationsDialogBuilder addOkButton() { dialog.okButton = new Button("OK"); dialog.okButton.setPrefWidth(BUTTON_WIDTH * 2); dialog.okButton.setOnAction( new EventHandler<ActionEvent>() { public void handle(ActionEvent t) { dialog.chosenConfiguration = getChosenConfiguration(); dependencyDotFileGenerator.generateOutputForConfigurations( preferences, dialog.chosenConfiguration, outputFileName, os); } }); dialog.buttonsPanel.getChildren().add(dialog.okButton); return this; }