EDIT

package eu.etaxonomy.cdm.vaadin.view;

import org.springframework.security.authentication.BadCredentialsException;

import org.springframework.security.core.Authentication;

import com.vaadin.annotations.AutoGenerated;

import com.vaadin.data.validator.StringLengthValidator;

import com.vaadin.event.ShortcutAction.KeyCode;

import com.vaadin.navigator.View;

import com.vaadin.navigator.ViewChangeListener.ViewChangeEvent;

import com.vaadin.server.VaadinSession;

import com.vaadin.ui.Alignment;

import com.vaadin.ui.Button;

import com.vaadin.ui.Button.ClickEvent;

import com.vaadin.ui.Button.ClickListener;

import com.vaadin.ui.CustomComponent;

import com.vaadin.ui.Notification;

import com.vaadin.ui.Panel;

import com.vaadin.ui.PasswordField;

import com.vaadin.ui.TextField;

import com.vaadin.ui.UI;

import com.vaadin.ui.VerticalLayout;

import eu.etaxonomy.cdm.vaadin.ui.AbstractAuthenticatedUI;

public class AuthenticationView extends CustomComponent implements IAuthenticationComponent, ClickListener , View {

	/*- VaadinEditorProperties={"grid":"RegularGrid,20","showGrid":true,"snapToGrid":true,"snapToObject":true,"movingGuides":false,"snappingDistance":10} */

	/**

	 * 

	 */

	private static final long serialVersionUID = 1L;

	@AutoGenerated

	private VerticalLayout mainLayout;

	@AutoGenerated

	private Panel loginPanel;

	@AutoGenerated

	private VerticalLayout loginPanelLayout;

	@AutoGenerated

	private Button loginBtn;

	@AutoGenerated

	private PasswordField passwordField;

	@AutoGenerated

	private TextField userNameTF;

	private AuthenticationComponentListener authListener;

	/**

	 * The constructor should first build the main layout, set the

	 * composition root and then do any custom initialization.

	 *

	 * The constructor will not be automatically regenerated by the

	 * visual editor.

	 */

	public AuthenticationView() {

		buildMainLayout();

		setCompositionRoot(mainLayout);

		userNameTF.addValidator(new StringLengthValidator("It must be 3-25 characters", 3, 25, false));

		userNameTF.setNullRepresentation("");

		userNameTF.focus();

		loginBtn.addClickListener(this);

		loginBtn.setClickShortcut(KeyCode.ENTER, null);

	}

	@Override

	public void addListener(AuthenticationComponentListener listener) {

		this.authListener = listener;

	}

	@Override

	public void buttonClick(ClickEvent event) {

		Authentication authentication = null;

		try {

			authentication = authListener.login(userNameTF.getValue(), passwordField.getValue());

		} catch(BadCredentialsException e){

			Notification.show("Bad credentials", Notification.Type.ERROR_MESSAGE);

		}

		if(authentication != null && authentication.isAuthenticated()) {			

			VaadinSession.getCurrent().setAttribute("authentication", authentication);	

			// we are sure that since we are in the authentication view that the 

			// current ui should be of type AbstractAuthenticatedUI

			AbstractAuthenticatedUI aaui = (AbstractAuthenticatedUI) UI.getCurrent();

			UI.getCurrent().getNavigator().navigateTo(aaui.getFirstViewName());

		} 

	}

	@Override

	public void enter(ViewChangeEvent event) {

		// TODO Auto-generated method stub

	}

	@AutoGenerated

	private VerticalLayout buildMainLayout() {

		// common part: create layout

		mainLayout = new VerticalLayout();

		mainLayout.setImmediate(false);

		mainLayout.setWidth("100%");

		mainLayout.setHeight("100%");

		mainLayout.setMargin(false);

		// top-level component properties

		setWidth("100.0%");

		setHeight("100.0%");

		// loginPanel

		loginPanel = buildLoginPanel();

		mainLayout.addComponent(loginPanel);

		mainLayout.setExpandRatio(loginPanel, 1.0f);

		mainLayout.setComponentAlignment(loginPanel, new Alignment(48));

		return mainLayout;

	}

	@AutoGenerated

	private Panel buildLoginPanel() {

		// common part: create layout

		loginPanel = new Panel();

		loginPanel.setImmediate(false);

		loginPanel.setWidth("-1px");

		loginPanel.setHeight("-1px");

		// loginPanelLayout

		loginPanelLayout = buildLoginPanelLayout();

		loginPanel.setContent(loginPanelLayout);

		return loginPanel;

	}

	@AutoGenerated

	private VerticalLayout buildLoginPanelLayout() {

		// common part: create layout

		loginPanelLayout = new VerticalLayout();

		loginPanelLayout.setImmediate(false);

		loginPanelLayout.setWidth("-1px");

		loginPanelLayout.setHeight("-1px");

		loginPanelLayout.setMargin(true);

		loginPanelLayout.setSpacing(true);

		// userNameTF

		userNameTF = new TextField();

		userNameTF.setCaption("User Name");

		userNameTF.setImmediate(false);

		userNameTF.setWidth("-1px");

		userNameTF.setHeight("-1px");

		userNameTF.setInvalidAllowed(false);

		userNameTF.setRequired(true);

		loginPanelLayout.addComponent(userNameTF);

		loginPanelLayout.setComponentAlignment(userNameTF, new Alignment(48));

		// passwordField

		passwordField = new PasswordField();

		passwordField.setCaption("Password");

		passwordField.setImmediate(false);

		passwordField.setWidth("-1px");

		passwordField.setHeight("-1px");

		passwordField.setInvalidAllowed(false);

		passwordField.setRequired(true);

		loginPanelLayout.addComponent(passwordField);

		loginPanelLayout

				.setComponentAlignment(passwordField, new Alignment(48));

		// loginBtn

		loginBtn = new Button();

		loginBtn.setCaption("Login");

		loginBtn.setImmediate(true);

		loginBtn.setWidth("-1px");

		loginBtn.setHeight("-1px");

		loginPanelLayout.addComponent(loginBtn);

		loginPanelLayout.setComponentAlignment(loginBtn, new Alignment(48));

		return loginPanelLayout;

	}

}