* Licensed to Apereo under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Apereo licenses this file to you 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 the following location:
 *   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
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
package org.jasig.cas.web.flow;

import org.jasig.cas.CentralAuthenticationService;
import org.jasig.cas.authentication.principal.NullPrincipal;
import org.jasig.cas.authentication.principal.Principal;
import org.jasig.cas.ticket.InvalidTicketException;
import org.jasig.cas.ticket.TicketGrantingTicket;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

 * Action that should execute prior to rendering the generic-success login view.
 * @author Misagh Moayyed
 * @since 4.1.0
public final class GenericSuccessViewAction {
    /** Log instance for logging events, info, warnings, errors, etc. */
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    private final CentralAuthenticationService centralAuthenticationService;

     * Instantiates a new Generic success view action.
     * @param centralAuthenticationService the central authentication service
    public GenericSuccessViewAction(final CentralAuthenticationService centralAuthenticationService) {
        this.centralAuthenticationService = centralAuthenticationService;

     * Gets authentication principal.
     * @param ticketGrantingTicketId the ticket granting ticket id
     * @return the authentication principal, or {@link org.jasig.cas.authentication.principal.NullPrincipal}
     * if none was available.
    public Principal getAuthenticationPrincipal(final String ticketGrantingTicketId) {
        try {
            final TicketGrantingTicket ticketGrantingTicket =
                    this.centralAuthenticationService.getTicket(ticketGrantingTicketId, TicketGrantingTicket.class);
            return ticketGrantingTicket.getAuthentication().getPrincipal();
        } catch (final InvalidTicketException e){
        logger.debug("In the absence of valid TGT, the authentication principal cannot be determined. Returning {}",
        return NullPrincipal.getInstance();