1/*
2 * Copyright (c) 1996, 2013, 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
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23 * questions.
24 */
25
26package java.security;
27
28import javax.security.auth.Subject;
29
30/**
31 * This interface represents the abstract notion of a principal, which
32 * can be used to represent any entity, such as an individual, a
33 * corporation, and a login id.
34 *
35 * @see java.security.cert.X509Certificate
36 *
37 * @author Li Gong
38 */
39public interface Principal {
40
41    /**
42     * Compares this principal to the specified object.  Returns true
43     * if the object passed in matches the principal represented by
44     * the implementation of this interface.
45     *
46     * @param another principal to compare with.
47     *
48     * @return true if the principal passed in is the same as that
49     * encapsulated by this principal, and false otherwise.
50     */
51    public boolean equals(Object another);
52
53    /**
54     * Returns a string representation of this principal.
55     *
56     * @return a string representation of this principal.
57     */
58    public String toString();
59
60    /**
61     * Returns a hashcode for this principal.
62     *
63     * @return a hashcode for this principal.
64     */
65    public int hashCode();
66
67    /**
68     * Returns the name of this principal.
69     *
70     * @return the name of this principal.
71     */
72    public String getName();
73
74    /**
75     * Returns true if the specified subject is implied by this principal.
76     *
77     * <p>The default implementation of this method returns true if
78     * {@code subject} is non-null and contains at least one principal that
79     * is equal to this principal.
80     *
81     * <p>Subclasses may override this with a different implementation, if
82     * necessary.
83     *
84     * @param subject the {@code Subject}
85     * @return true if {@code subject} is non-null and is
86     *              implied by this principal, or false otherwise.
87     * @since 1.8
88     */
89    public default boolean implies(Subject subject) {
90        if (subject == null)
91            return false;
92        return subject.getPrincipals().contains(this);
93    }
94}
95