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.authz.aop;
020    
021    import java.lang.annotation.Annotation;
022    
023    import org.apache.shiro.authz.AuthorizationException;
024    import org.apache.shiro.authz.UnauthenticatedException;
025    import org.apache.shiro.authz.annotation.RequiresUser;
026    
027    
028    /**
029     * Checks to see if a @{@link org.apache.shiro.authz.annotation.RequiresUser RequiresUser} annotation
030     * is declared, and if so, ensures the calling <code>Subject</code> is <em>either</em>
031     * {@link org.apache.shiro.subject.Subject#isAuthenticated() authenticated} <b><em>or</em></b> remembered via remember
032     * me services before allowing access.
033     * <p>
034     * This annotation essentially ensures that <code>subject.{@link org.apache.shiro.subject.Subject#getPrincipal() getPrincipal()} != null</code>.
035     *
036     * @since 0.9.0
037     */
038    public class UserAnnotationHandler extends AuthorizingAnnotationHandler {
039    
040        /**
041         * Default no-argument constructor that ensures this handler looks for
042         *
043         * {@link org.apache.shiro.authz.annotation.RequiresUser RequiresUser} annotations.
044         */
045        public UserAnnotationHandler() {
046            super(RequiresUser.class);
047        }
048    
049        /**
050         * Ensures that the calling <code>Subject</code> is a <em>user</em>, that is, they are <em>either</code>
051         * {@link org.apache.shiro.subject.Subject#isAuthenticated() authenticated} <b><em>or</em></b> remembered via remember
052         * me services before allowing access, and if not, throws an
053         * <code>AuthorizingException</code> indicating access is not allowed.
054         *
055         * @param a the RequiresUser annotation to check
056         * @throws org.apache.shiro.authz.AuthorizationException
057         *         if the calling <code>Subject</code> is not authenticated or remembered via rememberMe services.
058         */
059        public void assertAuthorized(Annotation a) throws AuthorizationException {
060            if (a instanceof RequiresUser && getSubject().getPrincipal() == null) {
061                throw new UnauthenticatedException("Attempting to perform a user-only operation.  The current Subject is " +
062                        "not a user (they haven't been authenticated or remembered from a previous login).  " +
063                        "Access denied.");
064            }
065        }
066    }