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.authz.aop;
20
21 import java.lang.annotation.Annotation;
22
23 import org.apache.shiro.authz.AuthorizationException;
24 import org.apache.shiro.authz.UnauthenticatedException;
25 import org.apache.shiro.authz.annotation.RequiresGuest;
26
27
28 /**
29 * Checks to see if a @{@link org.apache.shiro.authz.annotation.RequiresGuest RequiresGuest} annotation
30 * is declared, and if so, ensures the calling <code>Subject</code> does <em>not</em>
31 * have an {@link org.apache.shiro.subject.Subject#getPrincipal() identity} before invoking the method.
32 * <p>
33 * This annotation essentially ensures that <code>subject.{@link org.apache.shiro.subject.Subject#getPrincipal() getPrincipal()} == null</code>.
34 *
35 * @since 0.9.0
36 */
37 public class GuestAnnotationHandler extends AuthorizingAnnotationHandler {
38
39 /**
40 * Default no-argument constructor that ensures this interceptor looks for
41 *
42 * {@link org.apache.shiro.authz.annotation.RequiresGuest RequiresGuest} annotations in a method
43 * declaration.
44 */
45 public GuestAnnotationHandler() {
46 super(RequiresGuest.class);
47 }
48
49 /**
50 * Ensures that the calling <code>Subject</code> is NOT a <em>user</em>, that is, they do not
51 * have an {@link org.apache.shiro.subject.Subject#getPrincipal() identity} before continuing. If they are
52 * a user ({@link org.apache.shiro.subject.Subject#getPrincipal() Subject.getPrincipal()} != null), an
53 * <code>AuthorizingException</code> will be thrown indicating that execution is not allowed to continue.
54 *
55 * @param a the annotation to check for one or more roles
56 * @throws org.apache.shiro.authz.AuthorizationException
57 * if the calling <code>Subject</code> is not a "guest".
58 */
59 public void assertAuthorized(Annotation a) throws AuthorizationException {
60 if (a instanceof RequiresGuest && getSubject().getPrincipal() != null) {
61 throw new UnauthenticatedException("Attempting to perform a guest-only operation. The current Subject is " +
62 "not a guest (they have been authenticated or remembered from a previous login). Access " +
63 "denied.");
64 }
65 }
66 }