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.mgt;
020    
021    import org.apache.shiro.subject.Subject;
022    
023    /**
024     * A {@code SubjectDAO} is responsible for persisting a Subject instance's internal state such that the Subject instance
025     * can be recreated at a later time if necessary.
026     * <p/>
027     * Shiro's default {@code SecurityManager} implementations typically use a {@code SubjectDAO} in conjunction
028     * with a {@link SubjectFactory}: after the {@code SubjectFactory} creates a {@code Subject} instance, the
029     * {@code SubjectDAO} is used to persist that subject's state such that it can be accessed later if necessary.
030     * <h3>Usage</h3>
031     * It should be noted that this component is used by {@code SecurityManager} implementations to manage Subject
032     * state persistence.  It does <em>not</em> make Subject instances accessible to the
033     * application (e.g. via {@link org.apache.shiro.SecurityUtils#getSubject() SecurityUtils.getSubject()}).
034     *
035     * @see DefaultSubjectDAO
036     * @since 1.2
037     */
038    public interface SubjectDAO {
039    
040        /**
041         * Persists the specified Subject's state for later access.  If there is a no existing state persisted, this
042         * persists it if possible (i.e. a create operation).  If there is existing state for the specified {@code Subject},
043         * this method updates the existing state to reflect the current state (i.e. an update operation).
044         *
045         * @param subject the Subject instance for which its state will be created or updated.
046         * @return the Subject instance to use after persistence is complete.  This can be the same as the method argument
047         * if the underlying implementation does not need to make any Subject changes.
048         */
049        Subject save(Subject subject);
050    
051        /**
052         * Removes any persisted state for the specified {@code Subject} instance.  This is a delete operation such that
053         * the Subject's state will not be accessible at a later time.
054         *
055         * @param subject the Subject instance for which any persistent state should be deleted.
056         */
057        void delete(Subject subject);
058    }