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.authz.permission;
20
21 import org.apache.shiro.authz.Permission;
22
23 /**
24 * A {@code PermisisonResolver} resolves a String value and converts it into a
25 * {@link org.apache.shiro.authz.Permission Permission} instance.
26 * <p/>
27 * The default {@link WildcardPermissionResolver} should be
28 * suitable for most purposes, which constructs {@link WildcardPermission} objects.
29 * However, any resolver may be configured if an application wishes to use different
30 * {@link org.apache.shiro.authz.Permission} implementations.
31 * <p/>
32 * A {@code PermissionResolver} is used by many Shiro components such as annotations, property file
33 * configuration, URL configuration, etc. It is useful whenever a String representation of a permission is specified
34 * and that String needs to be converted to a Permission instance before executing a security check.
35 * <p/>
36 * Shiro chooses to support {@link WildcardPermission Wildcardpermission}s by default in almost all components and
37 * we do that in the form of the {@link WildcardPermissionResolver WildcardPermissionResolver}. One of the nice
38 * things about {@code WildcardPermission}s being supported by default is that it makes it very easy to
39 * store complex permissions in the database - and also makes it very easy to represent permissions in JSP files,
40 * annotations, etc., where a simple string representation is useful.
41 * <p/>
42 * Although this happens to be the Shiro default, you are of course free to provide custom
43 * String-to-Permission conversion by providing Shiro components any instance of this interface.
44 *
45 * @see org.apache.shiro.authz.ModularRealmAuthorizer#setPermissionResolver(PermissionResolver) ModularRealmAuthorizer.setPermissionResolver
46 * @see org.apache.shiro.realm.AuthorizingRealm#setPermissionResolver(PermissionResolver) AuthorizingRealm.setPermissionResolver
47 * @see PermissionResolverAware PermissionResolverAware
48 * @since 0.9
49 */
50 public interface PermissionResolver {
51
52 /**
53 * Resolves a Permission based on the given String representation.
54 *
55 * @param permissionString the String representation of a permission.
56 * @return A Permission object that can be used internally to determine a subject's permissions.
57 * @throws InvalidPermissionStringException
58 * if the permission string is not valid for this resolver.
59 */
60 Permission resolvePermission(String permissionString);
61
62 }