com.mcparland.john.vaadin_mvn_arch.samples.authentication.CurrentUser.java Source code

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Here is the source code for com.mcparland.john.vaadin_mvn_arch.samples.authentication.CurrentUser.java

Source

package com.mcparland.john.vaadin_mvn_arch.samples.authentication;

/*
 * #%L
 * vaadin_mvn_arch-ui
 * %%
 * Copyright (C) 2014 John McParland
 * %%
 * 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.
 * #L%
 */

import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinService;

/**
 * Class for retrieving and setting the name of the current user of the current
 * session (without using JAAS). All methods of this class require that a
 * {@link VaadinRequest} is bound to the current thread.
 * 
 * 
 * @see com.vaadin.server.VaadinService#getCurrentRequest()
 */
public final class CurrentUser {

    /**
     * The attribute key used to store the username in the session.
     */
    public static final String CURRENT_USER_SESSION_ATTRIBUTE_KEY = CurrentUser.class.getCanonicalName();

    private CurrentUser() {
    }

    /**
     * Returns the name of the current user stored in the current session, or an
     * empty string if no user name is stored.
     * 
     * @throws IllegalStateException
     *             if the current session cannot be accessed.
     */
    public static String get() {
        String currentUser = (String) getCurrentRequest().getWrappedSession()
                .getAttribute(CURRENT_USER_SESSION_ATTRIBUTE_KEY);
        if (currentUser == null) {
            return "";
        } else {
            return currentUser;
        }
    }

    /**
     * Sets the name of the current user and stores it in the current session.
     * Using a {@code null} username will remove the username from the session.
     * 
     * @throws IllegalStateException
     *             if the current session cannot be accessed.
     */
    public static void set(String currentUser) {
        if (currentUser == null) {
            getCurrentRequest().getWrappedSession().removeAttribute(CURRENT_USER_SESSION_ATTRIBUTE_KEY);
        } else {
            getCurrentRequest().getWrappedSession().setAttribute(CURRENT_USER_SESSION_ATTRIBUTE_KEY, currentUser);
        }
    }

    private static VaadinRequest getCurrentRequest() {
        VaadinRequest request = VaadinService.getCurrentRequest();
        if (request == null) {
            throw new IllegalStateException("No request bound to current thread");
        }
        return request;
    }
}