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.annotation;
020    
021    import java.lang.annotation.ElementType;
022    import java.lang.annotation.Retention;
023    import java.lang.annotation.RetentionPolicy;
024    import java.lang.annotation.Target;
025    
026    /**
027     * Requires the current Subject to be a &quot;guest&quot;, that is, they are not authenticated <em>or</em> remembered
028     * from a previous session for the annotated class/instance/method to be accessed or invoked.
029     * <p/>
030     * This annotation is the logical inverse of the {@link RequiresUser RequiresUser} annotation. That is,
031     * <code>RequiresUser == !RequiresGuest</code>, or more accurately,
032     * <p/>
033     * <code>RequiresGuest === subject.{@link org.apache.shiro.subject.Subject#getPrincipal() getPrincipal()} == null</code>.
034     *
035     * @see RequiresAuthentication
036     * @see RequiresUser
037     *
038     * @since 0.9.0
039     */
040    @Target({ElementType.TYPE, ElementType.METHOD})
041    @Retention(RetentionPolicy.RUNTIME)
042    public @interface RequiresGuest {
043    }