1 /*
2 * Copyright 2000-2003 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.security.cert;
27
28 import java.security.KeyStore;
29 import java.security.KeyStoreException;
30 import java.security.InvalidAlgorithmParameterException;
31 import java.security.InvalidParameterException;
32 import java.util.Set;
33
34 /**
35 * Parameters used as input for the PKIX <code>CertPathBuilder</code>
36 * algorithm.
37 * <p>
38 * A PKIX <code>CertPathBuilder</code> uses these parameters to {@link
39 * CertPathBuilder#build build} a <code>CertPath</code> which has been
40 * validated according to the PKIX certification path validation algorithm.
41 *
42 * <p>To instantiate a <code>PKIXBuilderParameters</code> object, an
43 * application must specify one or more <i>most-trusted CAs</i> as defined by
44 * the PKIX certification path validation algorithm. The most-trusted CA
45 * can be specified using one of two constructors. An application
46 * can call {@link #PKIXBuilderParameters(Set, CertSelector)
47 * PKIXBuilderParameters(Set, CertSelector)}, specifying a
48 * <code>Set</code> of <code>TrustAnchor</code> objects, each of which
49 * identifies a most-trusted CA. Alternatively, an application can call
50 * {@link #PKIXBuilderParameters(KeyStore, CertSelector)
51 * PKIXBuilderParameters(KeyStore, CertSelector)}, specifying a
52 * <code>KeyStore</code> instance containing trusted certificate entries, each
53 * of which will be considered as a most-trusted CA.
54 *
55 * <p>In addition, an application must specify constraints on the target
56 * certificate that the <code>CertPathBuilder</code> will attempt
57 * to build a path to. The constraints are specified as a
58 * <code>CertSelector</code> object. These constraints should provide the
59 * <code>CertPathBuilder</code> with enough search criteria to find the target
60 * certificate. Minimal criteria for an <code>X509Certificate</code> usually
61 * include the subject name and/or one or more subject alternative names.
62 * If enough criteria is not specified, the <code>CertPathBuilder</code>
63 * may throw a <code>CertPathBuilderException</code>.
64 * <p>
65 * <b>Concurrent Access</b>
66 * <p>
67 * Unless otherwise specified, the methods defined in this class are not
68 * thread-safe. Multiple threads that need to access a single
69 * object concurrently should synchronize amongst themselves and
70 * provide the necessary locking. Multiple threads each manipulating
71 * separate objects need not synchronize.
72 *
73 * @see CertPathBuilder
74 *
75 * @since 1.4
76 * @author Sean Mullan
77 */
78 public class PKIXBuilderParameters extends PKIXParameters {
79
80 private int maxPathLength = 5;
81
82 /**
83 * Creates an instance of <code>PKIXBuilderParameters</code> with
84 * the specified <code>Set</code> of most-trusted CAs.
85 * Each element of the set is a {@link TrustAnchor TrustAnchor}.
86 *
87 * <p>Note that the <code>Set</code> is copied to protect against
88 * subsequent modifications.
89 *
90 * @param trustAnchors a <code>Set</code> of <code>TrustAnchor</code>s
91 * @param targetConstraints a <code>CertSelector</code> specifying the
92 * constraints on the target certificate
93 * @throws InvalidAlgorithmParameterException if <code>trustAnchors</code>
94 * is empty <code>(trustAnchors.isEmpty() == true)</code>
95 * @throws NullPointerException if <code>trustAnchors</code> is
96 * <code>null</code>
97 * @throws ClassCastException if any of the elements of
98 * <code>trustAnchors</code> are not of type
99 * <code>java.security.cert.TrustAnchor</code>
100 */
101 public PKIXBuilderParameters(Set<TrustAnchor> trustAnchors, CertSelector
102 targetConstraints) throws InvalidAlgorithmParameterException
103 {
104 super(trustAnchors);
105 setTargetCertConstraints(targetConstraints);
106 }
107
108 /**
109 * Creates an instance of <code>PKIXBuilderParameters</code> that
110 * populates the set of most-trusted CAs from the trusted
111 * certificate entries contained in the specified <code>KeyStore</code>.
112 * Only keystore entries that contain trusted <code>X509Certificate</code>s
113 * are considered; all other certificate types are ignored.
114 *
115 * @param keystore a <code>KeyStore</code> from which the set of
116 * most-trusted CAs will be populated
117 * @param targetConstraints a <code>CertSelector</code> specifying the
118 * constraints on the target certificate
119 * @throws KeyStoreException if <code>keystore</code> has not been
120 * initialized
121 * @throws InvalidAlgorithmParameterException if <code>keystore</code> does
122 * not contain at least one trusted certificate entry
123 * @throws NullPointerException if <code>keystore</code> is
124 * <code>null</code>
125 */
126 public PKIXBuilderParameters(KeyStore keystore,
127 CertSelector targetConstraints)
128 throws KeyStoreException, InvalidAlgorithmParameterException
129 {
130 super(keystore);
131 setTargetCertConstraints(targetConstraints);
132 }
133
134 /**
135 * Sets the value of the maximum number of non-self-issued intermediate
136 * certificates that may exist in a certification path. A certificate
137 * is self-issued if the DNs that appear in the subject and issuer
138 * fields are identical and are not empty. Note that the last certificate
139 * in a certification path is not an intermediate certificate, and is not
140 * included in this limit. Usually the last certificate is an end entity
141 * certificate, but it can be a CA certificate. A PKIX
142 * <code>CertPathBuilder</code> instance must not build
143 * paths longer than the length specified.
144 *
145 * <p> A value of 0 implies that the path can only contain
146 * a single certificate. A value of -1 implies that the
147 * path length is unconstrained (i.e. there is no maximum).
148 * The default maximum path length, if not specified, is 5.
149 * Setting a value less than -1 will cause an exception to be thrown.
150 *
151 * <p> If any of the CA certificates contain the
152 * <code>BasicConstraintsExtension</code>, the value of the
153 * <code>pathLenConstraint</code> field of the extension overrides
154 * the maximum path length parameter whenever the result is a
155 * certification path of smaller length.
156 *
157 * @param maxPathLength the maximum number of non-self-issued intermediate
158 * certificates that may exist in a certification path
159 * @throws InvalidParameterException if <code>maxPathLength</code> is set
160 * to a value less than -1
161 *
162 * @see #getMaxPathLength
163 */
164 public void setMaxPathLength(int maxPathLength) {
165 if (maxPathLength < -1) {
166 throw new InvalidParameterException("the maximum path "
167 + "length parameter can not be less than -1");
168 }
169 this.maxPathLength = maxPathLength;
170 }
171
172 /**
173 * Returns the value of the maximum number of intermediate non-self-issued
174 * certificates that may exist in a certification path. See
175 * the {@link #setMaxPathLength} method for more details.
176 *
177 * @return the maximum number of non-self-issued intermediate certificates
178 * that may exist in a certification path, or -1 if there is no limit
179 *
180 * @see #setMaxPathLength
181 */
182 public int getMaxPathLength() {
183 return maxPathLength;
184 }
185
186 /**
187 * Returns a formatted string describing the parameters.
188 *
189 * @return a formatted string describing the parameters
190 */
191 public String toString() {
192 StringBuffer sb = new StringBuffer();
193 sb.append("[\n");
194 sb.append(super.toString());
195 sb.append(" Maximum Path Length: " + maxPathLength + "\n");
196 sb.append("]\n");
197 return sb.toString();
198 }
199 }
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