001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.web.tags;
020    
021    import javax.servlet.jsp.JspException;
022    
023    import org.slf4j.Logger;
024    import org.slf4j.LoggerFactory;
025    
026    
027    /**
028     * JSP tag that renders the tag body if the current user known to the system, either from a successful login attempt
029     * (not necessarily during the current session) or from 'RememberMe' services.
030     *
031     * <p><b>Note:</b> This is <em>less</em> restrictive than the <code>AuthenticatedTag</code> since it only assumes
032     * the user is who they say they are, either via a current session login <em>or</em> via Remember Me services, which
033     * makes no guarantee the user is who they say they are.  The <code>AuthenticatedTag</code> however
034     * guarantees that the current user has logged in <em>during their current session</em>, proving they really are
035     * who they say they are.
036     *
037     * <p>The logically opposite tag of this one is the {@link org.apache.shiro.web.tags.GuestTag}.
038     *
039     * @since 0.9
040     */
041    public class UserTag extends SecureTag {
042    
043        //TODO - complete JavaDoc
044    
045        private static final Logger log = LoggerFactory.getLogger(UserTag.class);
046    
047        public int onDoStartTag() throws JspException {
048            if (getSubject() != null && getSubject().getPrincipal() != null) {
049                if (log.isTraceEnabled()) {
050                    log.trace("Subject has known identity (aka 'principal').  " +
051                            "Tag body will be evaluated.");
052                }
053                return EVAL_BODY_INCLUDE;
054            } else {
055                if (log.isTraceEnabled()) {
056                    log.trace("Subject does not exist or have a known identity (aka 'principal').  " +
057                            "Tag body will not be evaluated.");
058                }
059                return SKIP_BODY;
060            }
061        }
062    
063    }