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.session.mgt.eis;
20
21 import org.apache.shiro.session.Session;
22 import org.apache.shiro.session.UnknownSessionException;
23 import org.apache.shiro.util.CollectionUtils;
24 import org.slf4j.Logger;
25 import org.slf4j.LoggerFactory;
26
27 import java.io.Serializable;
28 import java.util.Collection;
29 import java.util.Collections;
30 import java.util.concurrent.ConcurrentHashMap;
31 import java.util.concurrent.ConcurrentMap;
32
33
34 /**
35 * Simple memory-based implementation of the SessionDAO that stores all of its sessions in an in-memory
36 * {@link ConcurrentMap}. <b>This implementation does not page to disk and is therefore unsuitable for applications
37 * that could experience a large amount of sessions</b> and would therefore cause {@code OutOfMemoryException}s. It is
38 * <em>not</em> recommended for production use in most environments.
39 * <h2>Memory Restrictions</h2>
40 * If your application is expected to host many sessions beyond what can be stored in the
41 * memory available to the JVM, it is highly recommended to use a different {@code SessionDAO} implementation which
42 * uses a more expansive or permanent backing data store.
43 * <p/>
44 * In this case, it is recommended to instead use a custom
45 * {@link CachingSessionDAO} implementation that communicates with a higher-capacity data store of your choice
46 * (file system, database, etc).
47 * <h2>Changes in 1.0</h2>
48 * This implementation prior to 1.0 used to subclass the {@link CachingSessionDAO}, but this caused problems with many
49 * cache implementations that would expunge entries due to TTL settings, resulting in Sessions that would be randomly
50 * (and permanently) lost. The Shiro 1.0 release refactored this implementation to be 100% memory-based (without
51 * {@code Cache} usage to avoid this problem.
52 *
53 * @see CachingSessionDAO
54 * @since 0.1
55 */
56 public class MemorySessionDAO extends AbstractSessionDAO {
57
58 private static final Logger log = LoggerFactory.getLogger(MemorySessionDAO.class);
59
60 private ConcurrentMap<Serializable, Session> sessions;
61
62 public MemorySessionDAO() {
63 this.sessions = new ConcurrentHashMap<Serializable, Session>();
64 }
65
66 protected Serializable doCreate(Session session) {
67 Serializable sessionId = generateSessionId(session);
68 assignSessionId(session, sessionId);
69 storeSession(sessionId, session);
70 return sessionId;
71 }
72
73 protected Session/apache/shiro/session/Session.html#Session">Session storeSession(Serializable id, Session session) {
74 if (id == null) {
75 throw new NullPointerException("id argument cannot be null.");
76 }
77 return sessions.putIfAbsent(id, session);
78 }
79
80 protected Session doReadSession(Serializable sessionId) {
81 return sessions.get(sessionId);
82 }
83
84 public void update(Session session) throws UnknownSessionException {
85 storeSession(session.getId(), session);
86 }
87
88 public void delete(Session session) {
89 if (session == null) {
90 throw new NullPointerException("session argument cannot be null.");
91 }
92 Serializable id = session.getId();
93 if (id != null) {
94 sessions.remove(id);
95 }
96 }
97
98 public Collection<Session> getActiveSessions() {
99 Collection<Session> values = sessions.values();
100 if (CollectionUtils.isEmpty(values)) {
101 return Collections.emptySet();
102 } else {
103 return Collections.unmodifiableCollection(values);
104 }
105 }
106
107 }