Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.vaadin.ui; import java.io.ByteArrayInputStream; import java.io.InputStream; import java.io.Serializable; import java.lang.reflect.Method; import java.nio.charset.StandardCharsets; import java.util.HashMap; import java.util.Map; import com.vaadin.server.StreamResource; import com.vaadin.shared.ApplicationConstants; import com.vaadin.shared.Registration; import com.vaadin.shared.ui.loginform.LoginFormConstants; import com.vaadin.shared.ui.loginform.LoginFormRpc; import com.vaadin.shared.ui.loginform.LoginFormState; import com.vaadin.util.ReflectTools; /** * Login form with auto-completion and auto-fill for all major browsers. You can * derive from this class and implement the * {@link #createContent(com.vaadin.ui.TextField, com.vaadin.ui.PasswordField, com.vaadin.ui.Button)} * method to build the layout using the text fields and login button that are * passed to that method. The supplied components are specially treated so that * they work with password managers. * <p> * To customize the fields or to replace them with your own implementations, you * can override {@link #createUsernameField()}, {@link #createPasswordField()} * and {@link #createLoginButton()}. These methods are called automatically and * cannot be called by your code. Captions can be reset by overriding * {@link #getUsernameCaption()}, {@link #getPasswordCaption()} and * {@link #getLoginButtonCaption()}. * <p> * Note that the API of LoginForm changed significantly in Vaadin 7.7. * * @since 5.3 */ public class LoginForm extends AbstractSingleComponentContainer { /** * Event sent when the login form is submitted. */ public static class LoginEvent extends Component.Event { private final Map<String, String> params; /** * Creates a login event using the given source and the given * parameters. * * @param source * the source of the event * @param params */ private LoginEvent(LoginForm source, Map<String, String> params) { super(source); this.params = params; } @Override public LoginForm getSource() { return (LoginForm) super.getSource(); } /** * Gets the login parameter with the given name. * * @param name * the name of the parameter * @return the value of the parameter or null if no such parameter is * present */ public String getLoginParameter(String name) { return params.get(name); } } /** * Listener triggered when a login occurs in a {@link LoginForm}. */ @FunctionalInterface public interface LoginListener extends Serializable { /** * Event method invoked when the login button is pressed in a login * form. * * @param event * the login event */ public void onLogin(LoginEvent event); } /** * Internal stream source for the login URL - always returns "Success" and * ignores the values received. */ private static class LoginStreamSource implements StreamResource.StreamSource { @Override public InputStream getStream() { return new ByteArrayInputStream("<html>Success</html>".getBytes(StandardCharsets.UTF_8)); } } private static final Method ON_LOGIN_METHOD = ReflectTools.findMethod(LoginListener.class, "onLogin", LoginEvent.class); private boolean initialized; private String usernameCaption = "Username"; private String passwordCaption = "Password"; private String loginButtonCaption = "Login"; /** * Customize the user name field. Only for overriding, do not call. * * @return the user name field * @since 7.7 */ protected TextField createUsernameField() { throwIfInitialized(); TextField field = new TextField(getUsernameCaption()); field.focus(); return field; } /** * Gets the caption set with {@link #setUsernameCaption(String)}. Note that * this method might not match what is shown to the user if * {@link #createUsernameField()} has been overridden. * * @return the user name field caption */ public String getUsernameCaption() { return usernameCaption; } /** * Sets the caption of the user name field. Note that the caption can only * be set with this method before the login form has been initialized * (attached). * <p> * As an alternative to calling this method, the method * {@link #createUsernameField()} can be overridden. * * @param usernameCaption * the caption to set for the user name field */ public void setUsernameCaption(String usernameCaption) { this.usernameCaption = usernameCaption; } /** * Customize the password field. Only for overriding, do not call. * * @return the password field * @since 7.7 */ protected PasswordField createPasswordField() { throwIfInitialized(); return new PasswordField(getPasswordCaption()); } /** * Gets the caption set with {@link #setPasswordCaption(String)}. Note that * this method might not match what is shown to the user if * {@link #createPasswordField()} has been overridden. * * * @return the password field caption */ public String getPasswordCaption() { return passwordCaption; } /** * Set the caption of the password field. Note that the caption can only be * set with this method before the login form has been initialized * (attached). * <p> * As an alternative to calling this method, the method * {@link #createPasswordField()} can be overridden. * * @param passwordCaption * the caption for the password field */ public void setPasswordCaption(String passwordCaption) { this.passwordCaption = passwordCaption; } /** * Customize the login button. Only for overriding, do not call. * * @return the login button * @since 7.7 */ protected Button createLoginButton() { throwIfInitialized(); return new Button(getLoginButtonCaption()); } /** * Gets the caption set with {@link #setLoginButtonCaption(String)}. Note * that this method might not match what is shown to the user if * {@link #createLoginButton()} has been overridden. * * @return the login button caption */ public String getLoginButtonCaption() { return loginButtonCaption; } /** * Sets the caption of the login button. Note that the caption can only be * set with this method before the login form has been initialized * (attached). * <p> * As an alternative to calling this method, the method * {@link #createLoginButton()} can be overridden. * * @param loginButtonCaption * new caption */ public void setLoginButtonCaption(String loginButtonCaption) { this.loginButtonCaption = loginButtonCaption; } @Override protected LoginFormState getState() { return (LoginFormState) super.getState(); } @Override protected LoginFormState getState(boolean markAsDirty) { return (LoginFormState) super.getState(markAsDirty); } @Override public void attach() { super.attach(); init(); } private void throwIfInitialized() { if (initialized) { throw new IllegalStateException( "Already initialized. The create methods may not be called explicitly."); } } /** * Create the content for the login form with the supplied user name field, * password field and the login button. You cannot use any other text fields * or buttons for this purpose. To replace these components with your own * implementations, override {@link #createUsernameField()}, * {@link #createPasswordField()} and {@link #createLoginButton()}. If you * only want to change the default captions, override * {@link #getUsernameCaption()}, {@link #getPasswordCaption()} and * {@link #getLoginButtonCaption()}. You do not have to use the login button * in your layout. * * @param userNameField * the user name text field * @param passwordField * the password field * @param loginButton * the login button * @return content component * @since 7.7 */ protected Component createContent(TextField userNameField, PasswordField passwordField, Button loginButton) { VerticalLayout layout = new VerticalLayout(); layout.setSpacing(true); layout.setMargin(true); layout.addComponent(userNameField); layout.addComponent(passwordField); layout.addComponent(loginButton); return layout; } private void init() { if (initialized) { return; } LoginFormState state = getState(); state.userNameFieldConnector = createUsernameField(); state.passwordFieldConnector = createPasswordField(); state.loginButtonConnector = createLoginButton(); StreamResource resource = new StreamResource(new LoginStreamSource(), LoginFormConstants.LOGIN_RESOURCE_NAME); resource.setMIMEType(ApplicationConstants.CONTENT_TYPE_TEXT_HTML_UTF_8); resource.setCacheTime(-1); setResource(LoginFormConstants.LOGIN_RESOURCE_NAME, resource); registerRpc((LoginFormRpc) this::login); initialized = true; setContent(createContent(getUsernameField(), getPasswordField(), getLoginButton())); } private TextField getUsernameField() { assert initialized; return (TextField) getState(false).userNameFieldConnector; } private PasswordField getPasswordField() { assert initialized; return (PasswordField) getState(false).passwordFieldConnector; } private Button getLoginButton() { assert initialized; return (Button) getState(false).loginButtonConnector; } /** * Handles the login. * <p> * In deferred mode, this method is called after the dummy POST request that * triggers the password manager has been completed. In direct mode (the * default setting), it is called directly when the user hits the enter key * or clicks on the login button. In the latter case, you cannot change the * URL in the method or the password manager will not be triggered. */ private void login() { Map<String, String> params = new HashMap<>(); params.put("username", getUsernameField().getValue()); params.put("password", getPasswordField().getValue()); LoginEvent event = new LoginEvent(LoginForm.this, params); fireEvent(event); } /** * Adds a {@link LoginListener}. * <p> * The listener is called when the user presses the login button. * * @param listener * the listener to add * @return a registration object for removing the listener * @since 8.0 */ public Registration addLoginListener(LoginListener listener) { return addListener(LoginEvent.class, listener, ON_LOGIN_METHOD); } /** * Removes a {@link LoginListener}. * * @param listener * the listener to remove * @deprecated As of 8.0, replaced by {@link Registration#remove()} in the * registration object returned from * {@link #addLoginListener(LoginListener)}. */ @Deprecated public void removeLoginListener(LoginListener listener) { removeListener(LoginEvent.class, listener, ON_LOGIN_METHOD); } }