SimpleLoginView.java

package com.vaadin.tests.minitutorials.v70;

import com.vaadin.navigator.View;
import com.vaadin.navigator.ViewChangeListener.ViewChangeEvent;
import com.vaadin.shared.ui.MarginInfo;
import com.vaadin.ui.Alignment;
import com.vaadin.ui.Button;
import com.vaadin.ui.Button.ClickEvent;
import com.vaadin.ui.CustomComponent;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.v7.data.validator.AbstractValidator;
import com.vaadin.v7.data.validator.EmailValidator;
import com.vaadin.v7.ui.PasswordField;
import com.vaadin.v7.ui.TextField;
import com.vaadin.v7.ui.themes.Reindeer;

public class SimpleLoginView extends CustomComponent
        implements View, Button.ClickListener {

    public static final String NAME = "login";

    private final TextField user;

    private final PasswordField password;

    private final Button loginButton;

    public SimpleLoginView() {
        setSizeFull();

        // Create the user input field
        user = new TextField("User:");
        user.setWidth("300px");
        user.setRequired(true);
        user.setInputPrompt("Your username (eg. joe@email.com)");
        user.addValidator(
                new EmailValidator("Username must be an email address"));
        user.setInvalidAllowed(false);

        // Create the password input field
        password = new PasswordField("Password:");
        password.setWidth("300px");
        password.addValidator(new PasswordValidator());
        password.setRequired(true);
        password.setValue("");
        password.setNullRepresentation("");

        // Create login button
        loginButton = new Button("Login", this);

        // Add both to a panel
        VerticalLayout fields = new VerticalLayout(user, password, loginButton);
        fields.setCaption(
                "Please login to access the application. (test@test.com/passw0rd)");
        fields.setSpacing(true);
        fields.setMargin(new MarginInfo(true, true, true, false));
        fields.setSizeUndefined();

        // The view root layout
        VerticalLayout viewLayout = new VerticalLayout(fields);
        viewLayout.setSizeFull();
        viewLayout.setComponentAlignment(fields, Alignment.MIDDLE_CENTER);
        viewLayout.setStyleName(Reindeer.LAYOUT_BLUE);
        setCompositionRoot(viewLayout);
    }

    @Override
    public void enter(ViewChangeEvent event) {
        // focus the username field when user arrives to the login view
        user.focus();
    }

    /*
     * Validator for validating the passwords
     */
    private static final class PasswordValidator
            extends AbstractValidator<String> {

        public PasswordValidator() {
            super("The password provided is not valid");
        }

        @Override
        protected boolean isValidValue(String value) {
            /*
             * Password must be at least 8 characters long and contain at least
             * one number
             */
            if (value != null
                    && (value.length() < 8 || !value.matches(".*\\d.*"))) {
                return false;
            }
            return true;
        }

        @Override
        public Class<String> getType() {
            return String.class;
        }
    }

    @Override
    public void buttonClick(ClickEvent event) {

        /*
         * Validate the fields using the navigator. By using validors for the
         * fields we reduce the amount of queries we have to use to the database
         * for wrongly entered passwords
         */
        if (!user.isValid() || !password.isValid()) {
            return;
        }

        String username = user.getValue();
        String password = this.password.getValue();

        /*
         * Validate username and password with database here. For examples sake
         * I use a dummy username and password.
         */
        boolean isValid = username.equals("test@test.com")
                && password.equals("passw0rd");

        if (isValid) {
            // Store the current user in the service session
            getSession().setAttribute("user", username);

            // Navigate to main view
            getUI().getNavigator().navigateTo(SimpleLoginMainView.NAME);

        } else {

            // Wrong password clear the password field and refocuses it
            this.password.setValue(null);
            this.password.focus();
        }
    }
}