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.mgt;
20
21 import org.apache.shiro.subject.Subject;
22
23 /**
24 * Evaluates whether or not Shiro may use a {@code Subject}'s {@link org.apache.shiro.session.Session Session}
25 * to persist that {@code Subject}'s internal state.
26 * <p/>
27 * It is a common Shiro implementation strategy to use a Subject's session to persist the Subject's identity and
28 * authentication state (e.g. after login) so that information does not need to be passed around for any further
29 * requests/invocations. This effectively allows a session id to be used for any request or invocation as the only
30 * 'pointer' that Shiro needs, and from that, Shiro can re-create the Subject instance based on the referenced Session.
31 * <p/>
32 * However, in purely stateless applications, such as some REST applications or those where every request is
33 * authenticated, it is usually not needed or desirable to use Sessions to store this state (since it is in
34 * fact re-created on every request). In these applications, sessions would never be used.
35 * <p/>
36 * This interface allows implementations to determine exactly when a Session might be used or not to store
37 * {@code Subject} state on a <em>per-Subject</em> basis.
38 * <p/>
39 * If you simply wish to enable or disable session usage at a global level for all {@code Subject}s, the
40 * {@link DefaultSessionStorageEvaluator} should be sufficient. Per-subject behavior should be performed in custom
41 * implementations of this interface.
42 *
43 * @see Subject#getSession()
44 * @see Subject#getSession(boolean)
45 * @see DefaultSessionStorageEvaluator
46 * @since 1.2
47 */
48 public interface SessionStorageEvaluator {
49
50 /**
51 * Returns {@code true} if the specified {@code Subject}'s
52 * {@link org.apache.shiro.subject.Subject#getSession() session} may be used to persist that Subject's
53 * state, {@code false} otherwise.
54 *
55 * @param subject the {@code Subject} for which session state persistence may be enabled
56 * @return {@code true} if the specified {@code Subject}'s
57 * {@link org.apache.shiro.subject.Subject#getSession() session} may be used to persist that Subject's
58 * state, {@code false} otherwise.
59 * @see Subject#getSession()
60 * @see Subject#getSession(boolean)
61 */
62 boolean isSessionStorageEnabled(Subject subject);
63
64 }