001 /* CertPathBuilder.java -- bulids CertPath objects from Certificates.
002 Copyright (C) 2003, 2004 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.security.cert;
040
041 import gnu.java.lang.CPStringBuilder;
042
043 import gnu.java.security.Engine;
044
045 import java.lang.reflect.InvocationTargetException;
046 import java.security.InvalidAlgorithmParameterException;
047 import java.security.NoSuchAlgorithmException;
048 import java.security.NoSuchProviderException;
049 import java.security.Provider;
050 import java.security.Security;
051
052 /**
053 * This class builds certificate paths (also called certificate chains),
054 * which can be used to establish trust for a particular certificate by
055 * building a path from a trusted certificate (a trust anchor) to the
056 * untrusted certificate.
057 *
058 * @see CertPath
059 */
060 public class CertPathBuilder
061 {
062
063 // Constants and fields.
064 // ------------------------------------------------------------------------
065
066 /** Service name for CertPathBuilder. */
067 private static final String CERT_PATH_BUILDER = "CertPathBuilder";
068
069 /** The underlying implementation. */
070 private CertPathBuilderSpi cpbSpi;
071
072 /** The provider of this implementation. */
073 private Provider provider;
074
075 /** The name of this implementation. */
076 private String algorithm;
077
078 // Constructor.
079 // ------------------------------------------------------------------------
080
081 /**
082 * Creates a new CertPathBuilder.
083 *
084 * @param cpbSpi The underlying implementation.
085 * @param provider The provider of the implementation.
086 * @param algorithm This implementation's name.
087 */
088 protected CertPathBuilder(CertPathBuilderSpi cpbSpi, Provider provider,
089 String algorithm)
090 {
091 this.cpbSpi = cpbSpi;
092 this.provider = provider;
093 this.algorithm = algorithm;
094 }
095
096 // Class methods.
097 // ------------------------------------------------------------------------
098
099 /**
100 * Get the default cert path builder type.
101 *
102 * <p>This value can be set at run-time by the security property
103 * <code>"certpathbuilder.type"</code>. If this property is not set,
104 * then the value returned is <code>"PKIX"</code>.
105 *
106 * @return The default CertPathBuilder algorithm.
107 */
108 public static final String getDefaultType()
109 {
110 String type = Security.getProperty("certpathbuilder.type");
111 if (type == null)
112 type = "PKIX";
113 return type;
114 }
115
116 /**
117 * Returns an instance of a named <code>CertPathBuilder</code> from the
118 * first provider that implements it.
119 *
120 * @param algorithm The name of the <code>CertPathBuilder</code> to create.
121 * @return The new instance.
122 * @throws NoSuchAlgorithmException If no installed provider implements the
123 * named algorithm.
124 * @throws IllegalArgumentException if <code>algorithm</code> is
125 * <code>null</code> or is an empty string.
126 */
127 public static CertPathBuilder getInstance(String algorithm)
128 throws NoSuchAlgorithmException
129 {
130 Provider[] p = Security.getProviders();
131 NoSuchAlgorithmException lastException = null;
132 for (int i = 0; i < p.length; i++)
133 try
134 {
135 return getInstance(algorithm, p[i]);
136 }
137 catch (NoSuchAlgorithmException x)
138 {
139 lastException = x;
140 }
141 if (lastException != null)
142 throw lastException;
143 throw new NoSuchAlgorithmException(algorithm);
144 }
145
146 /**
147 * Returns an instance of a named <code>CertPathBuilder</code> from a named
148 * provider.
149 *
150 * @param algorithm The name of the <code>CertPathBuilder</code> to create.
151 * @param provider The name of the provider to use.
152 * @return The new instance.
153 * @throws NoSuchAlgorithmException If no installed provider implements the
154 * named algorithm.
155 * @throws NoSuchProviderException If the named provider does not exist.
156 * @throws IllegalArgumentException if either <code>algorithm</code> or
157 * <code>provider</code> is <code>null</code>, or if
158 * <code>algorithm</code> is an empty string.
159 */
160 public static CertPathBuilder getInstance(String algorithm, String provider)
161 throws NoSuchAlgorithmException, NoSuchProviderException
162 {
163 if (provider == null)
164 throw new IllegalArgumentException("provider MUST NOT be null");
165 Provider p = Security.getProvider(provider);
166 if (p == null)
167 throw new NoSuchProviderException(provider);
168 return getInstance(algorithm, p);
169 }
170
171 /**
172 * Returns an instance of a named <code>CertPathBuilder</code> from the
173 * specified provider.
174 *
175 * @param algorithm The name of the <code>CertPathBuilder</code> to create.
176 * @param provider The provider to use.
177 * @return The new instance.
178 * @throws NoSuchAlgorithmException If no installed provider implements the
179 * named algorithm.
180 * @throws IllegalArgumentException if either <code>algorithm</code> or
181 * <code>provider</code> is <code>null</code>, or if
182 * <code>algorithm</code> is an empty string.
183 */
184 public static CertPathBuilder getInstance(String algorithm, Provider provider)
185 throws NoSuchAlgorithmException
186 {
187 CPStringBuilder sb = new CPStringBuilder("CertPathBuilder for algorithm [")
188 .append(algorithm).append("] from provider[")
189 .append(provider).append("] could not be created");
190 Throwable cause;
191 try
192 {
193 Object spi = Engine.getInstance(CERT_PATH_BUILDER, algorithm, provider);
194 return new CertPathBuilder((CertPathBuilderSpi) spi, provider, algorithm);
195 }
196 catch (InvocationTargetException x)
197 {
198 cause = x.getCause();
199 if (cause instanceof NoSuchAlgorithmException)
200 throw (NoSuchAlgorithmException) cause;
201 if (cause == null)
202 cause = x;
203 }
204 catch (ClassCastException x)
205 {
206 cause = x;
207 }
208 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString());
209 x.initCause(cause);
210 throw x;
211 }
212
213 /**
214 * Return the name of this CertPathBuilder algorithm.
215 *
216 * @return The algorithm name.
217 */
218 public final String getAlgorithm()
219 {
220 return algorithm;
221 }
222
223 /**
224 * Return the provider of this instance's implementation.
225 *
226 * @return The provider.
227 */
228 public final Provider getProvider()
229 {
230 return provider;
231 }
232
233 /**
234 * Builds a certificate path. The {@link CertPathParameters} parameter
235 * passed to this method is implementation-specific, but in general
236 * should contain some number of certificates and some number of
237 * trusted certificates (or "trust anchors").
238 *
239 * @param params The parameters.
240 * @retrun The certificate path result.
241 * @throws CertPathBuilderException If the certificate path cannot be
242 * built.
243 * @throws InvalidAlgorithmParameterException If the implementation
244 * rejects the specified parameters.
245 */
246 public final CertPathBuilderResult build(CertPathParameters params)
247 throws CertPathBuilderException, InvalidAlgorithmParameterException
248 {
249 return cpbSpi.engineBuild(params);
250 }
251 }