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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.shiro.web.tags;
20  
21  import javax.servlet.jsp.JspException;
22  
23  import org.slf4j.Logger;
24  import org.slf4j.LoggerFactory;
25  
26  
27  /**
28   * JSP tag that renders the tag body if the current user known to the system, either from a successful login attempt
29   * (not necessarily during the current session) or from 'RememberMe' services.
30   *
31   * <p><b>Note:</b> This is <em>less</em> restrictive than the <code>AuthenticatedTag</code> since it only assumes
32   * the user is who they say they are, either via a current session login <em>or</em> via Remember Me services, which
33   * makes no guarantee the user is who they say they are.  The <code>AuthenticatedTag</code> however
34   * guarantees that the current user has logged in <em>during their current session</em>, proving they really are
35   * who they say they are.
36   *
37   * <p>The logically opposite tag of this one is the {@link org.apache.shiro.web.tags.GuestTag}.
38   *
39   * @since 0.9
40   */
41  public class UserTag extends SecureTag {
42  
43      //TODO - complete JavaDoc
44  
45      private static final Logger log = LoggerFactory.getLogger(UserTag.class);
46  
47      public int onDoStartTag() throws JspException {
48          if (getSubject() != null && getSubject().getPrincipal() != null) {
49              if (log.isTraceEnabled()) {
50                  log.trace("Subject has known identity (aka 'principal').  " +
51                          "Tag body will be evaluated.");
52              }
53              return EVAL_BODY_INCLUDE;
54          } else {
55              if (log.isTraceEnabled()) {
56                  log.trace("Subject does not exist or have a known identity (aka 'principal').  " +
57                          "Tag body will not be evaluated.");
58              }
59              return SKIP_BODY;
60          }
61      }
62  
63  }