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 import javax.servlet.jsp.tagext.TagSupport;
23
24 import org.slf4j.Logger;
25 import org.slf4j.LoggerFactory;
26
27
28 /**
29 * JSP tag that renders the tag body if the current user <em>is not</em> known to the system, either because they
30 * haven't logged in yet, or because they have no 'RememberMe' identity.
31 *
32 * <p>The logically opposite tag of this one is the {@link UserTag}. Please read that class's JavaDoc as it explains
33 * more about the differences between Authenticated/Unauthenticated and User/Guest semantic differences.
34 *
35 * @since 0.9
36 */
37 public class GuestTag extends SecureTag {
38
39 //TODO - complete JavaDoc
40
41 private static final Logger log = LoggerFactory.getLogger(GuestTag.class);
42
43 public int onDoStartTag() throws JspException {
44 if (getSubject() == null || getSubject().getPrincipal() == null) {
45 if (log.isTraceEnabled()) {
46 log.trace("Subject does not exist or does not have a known identity (aka 'principal'). " +
47 "Tag body will be evaluated.");
48 }
49 return TagSupport.EVAL_BODY_INCLUDE;
50 } else {
51 if (log.isTraceEnabled()) {
52 log.trace("Subject exists or has a known identity (aka 'principal'). " +
53 "Tag body will not be evaluated.");
54 }
55 return TagSupport.SKIP_BODY;
56 }
57 }
58
59 }