1/*
2 * Copyright (c) 2007, 2009, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package java.nio.file.attribute;
27
28import java.io.IOException;
29
30/**
31 * An object to lookup user and group principals by name. A {@link UserPrincipal}
32 * represents an identity that may be used to determine access rights to objects
33 * in a file system. A {@link GroupPrincipal} represents a <em>group identity</em>.
34 * A {@code UserPrincipalLookupService} defines methods to lookup identities by
35 * name or group name (which are typically user or account names). Whether names
36 * and group names are case sensitive or not depends on the implementation.
37 * The exact definition of a group is implementation specific but typically a
38 * group represents an identity created for administrative purposes so as to
39 * determine the access rights for the members of the group. In particular it is
40 * implementation specific if the <em>namespace</em> for names and groups is the
41 * same or is distinct. To ensure consistent and correct behavior across
42 * platforms it is recommended that this API be used as if the namespaces are
43 * distinct. In other words, the {@link #lookupPrincipalByName
44 * lookupPrincipalByName} should be used to lookup users, and {@link
45 * #lookupPrincipalByGroupName lookupPrincipalByGroupName} should be used to
46 * lookup groups.
47 *
48 * @since 1.7
49 *
50 * @see java.nio.file.FileSystem#getUserPrincipalLookupService
51 */
52
53public abstract class UserPrincipalLookupService {
54
55    /**
56     * Initializes a new instance of this class.
57     */
58    protected UserPrincipalLookupService() {
59    }
60
61    /**
62     * Lookup a user principal by name.
63     *
64     * @param   name
65     *          the string representation of the user principal to lookup
66     *
67     * @return  a user principal
68     *
69     * @throws  UserPrincipalNotFoundException
70     *          the principal does not exist
71     * @throws  IOException
72     *          if an I/O error occurs
73     * @throws  SecurityException
74     *          In the case of the default provider, and a security manager is
75     *          installed, it checks {@link RuntimePermission}<tt>("lookupUserInformation")</tt>
76     */
77    public abstract UserPrincipal lookupPrincipalByName(String name)
78        throws IOException;
79
80    /**
81     * Lookup a group principal by group name.
82     *
83     * <p> Where an implementation does not support any notion of group then
84     * this method always throws {@link UserPrincipalNotFoundException}. Where
85     * the namespace for user accounts and groups is the same, then this method
86     * is identical to invoking {@link #lookupPrincipalByName
87     * lookupPrincipalByName}.
88     *
89     * @param   group
90     *          the string representation of the group to lookup
91     *
92     * @return  a group principal
93     *
94     * @throws  UserPrincipalNotFoundException
95     *          the principal does not exist or is not a group
96     * @throws  IOException
97     *          if an I/O error occurs
98     * @throws  SecurityException
99     *          In the case of the default provider, and a security manager is
100     *          installed, it checks {@link RuntimePermission}<tt>("lookupUserInformation")</tt>
101     */
102    public abstract GroupPrincipal lookupPrincipalByGroupName(String group)
103        throws IOException;
104}
105