001 /* AlgorithmParameters.java --- Algorithm Parameters Implementation Class
002 Copyright (C) 1999, 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;
040
041 import gnu.java.lang.CPStringBuilder;
042
043 import gnu.java.security.Engine;
044
045 import java.io.IOException;
046 import java.lang.reflect.InvocationTargetException;
047 import java.security.spec.AlgorithmParameterSpec;
048 import java.security.spec.InvalidParameterSpecException;
049
050 /**
051 * <code>AlgorithmParameters</code> is an Algorithm Parameters class which
052 * provides an interface through which the user can manage the parameters of an
053 * Algorithm.
054 *
055 * @author Mark Benvenuto
056 * @since 1.2
057 * @see AlgorithmParameterSpec
058 * @see java.security.spec.DSAParameterSpec
059 * @see KeyPairGenerator
060 */
061 public class AlgorithmParameters
062 {
063 /** Service name for algorithm parameters. */
064 private static final String ALGORITHM_PARAMETERS = "AlgorithmParameters";
065
066 private AlgorithmParametersSpi paramSpi;
067 private Provider provider;
068 private String algorithm;
069
070 /**
071 * Constructs a new instance of <code>AlgorithmParameters</code>.
072 *
073 * @param paramSpi
074 * the engine to use.
075 * @param provider
076 * the provider to use.
077 * @param algorithm
078 * the algorithm to use.
079 */
080 protected AlgorithmParameters(AlgorithmParametersSpi paramSpi,
081 Provider provider, String algorithm)
082 {
083 this.paramSpi = paramSpi;
084 this.provider = provider;
085 this.algorithm = algorithm;
086 }
087
088 /** @return A string with the name of the algorithm used. */
089 public final String getAlgorithm()
090 {
091 return algorithm;
092 }
093
094 /**
095 * Returns a new instance of <code>AlgorithmParameters</code> representing
096 * the specified algorithm parameters.
097 * <p>
098 * The returned <code>AlgorithmParameters</code> must still be initialized
099 * with an <code>init()</code> method.
100 *
101 * @param algorithm the algorithm to use.
102 * @return the new instance repesenting the desired algorithm.
103 * @throws NoSuchAlgorithmException if the algorithm is not implemented by any
104 * provider.
105 * @throws IllegalArgumentException if <code>algorithm</code> is
106 * <code>null</code> or is an empty string.
107 */
108 public static AlgorithmParameters getInstance(String algorithm)
109 throws NoSuchAlgorithmException
110 {
111 Provider[] p = Security.getProviders();
112 NoSuchAlgorithmException lastException = null;
113 for (int i = 0; i < p.length; i++)
114 try
115 {
116 return getInstance(algorithm, p[i]);
117 }
118 catch (NoSuchAlgorithmException x)
119 {
120 lastException = x;
121 }
122 if (lastException != null)
123 throw lastException;
124 throw new NoSuchAlgorithmException(algorithm);
125 }
126
127 /**
128 * Returns a new instance of <code>AlgorithmParameters</code> representing
129 * the specified algorithm parameters from a named provider.
130 * <p>
131 * The returned <code>AlgorithmParameters</code> must still be intialized
132 * with an <code>init()</code> method.
133 * </p>
134 *
135 * @param algorithm the algorithm to use.
136 * @param provider the name of the {@link Provider} to use.
137 * @return the new instance repesenting the desired algorithm.
138 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the
139 * named provider.
140 * @throws NoSuchProviderException if the named provider was not found.
141 * @throws IllegalArgumentException if either <code>algorithm</code> or
142 * <code>provider</code> is <code>null</code> or empty.
143 */
144 public static AlgorithmParameters getInstance(String algorithm,
145 String provider)
146 throws NoSuchAlgorithmException, NoSuchProviderException
147 {
148 if (provider == null)
149 throw new IllegalArgumentException("provider MUST NOT be null");
150 provider = provider.trim();
151 if (provider.length() == 0)
152 throw new IllegalArgumentException("provider MUST NOT be empty");
153 Provider p = Security.getProvider(provider);
154 if (p == null)
155 throw new NoSuchProviderException(provider);
156 return getInstance(algorithm, p);
157 }
158
159 /**
160 * Returns a new instance of <code>AlgorithmParameters</code> representing
161 * the specified algorithm parameters from the specified {@link Provider}.
162 * <p>
163 * The returned <code>AlgorithmParameters</code> must still be intialized
164 * with an <code>init()</code> method.
165 *
166 * @param algorithm the algorithm to use.
167 * @param provider the {@link Provider} to use.
168 * @return the new instance repesenting the desired algorithm.
169 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the
170 * {@link Provider}.
171 * @throws IllegalArgumentException if either <code>algorithm</code> or
172 * <code>provider</code> is <code>null</code>, or if
173 * <code>algorithm</code> is an empty string.
174 * @since 1.4
175 */
176 public static AlgorithmParameters getInstance(String algorithm,
177 Provider provider)
178 throws NoSuchAlgorithmException
179 {
180 CPStringBuilder sb = new CPStringBuilder("AlgorithmParameters for algorithm [")
181 .append(algorithm).append("] from provider[")
182 .append(provider).append("] could not be created");
183 Throwable cause;
184 try
185 {
186 Object spi = Engine.getInstance(ALGORITHM_PARAMETERS, algorithm, provider);
187 return new AlgorithmParameters((AlgorithmParametersSpi) spi,
188 provider,
189 algorithm);
190 }
191 catch (InvocationTargetException x)
192 {
193 cause = x.getCause();
194 if (cause instanceof NoSuchAlgorithmException)
195 throw (NoSuchAlgorithmException) cause;
196 if (cause == null)
197 cause = x;
198 }
199 catch (ClassCastException x)
200 {
201 cause = x;
202 }
203 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString());
204 x.initCause(cause);
205 throw x;
206 }
207
208 /** @return the provider of this parameter object. */
209 public final Provider getProvider()
210 {
211 return provider;
212 }
213
214 /**
215 * Initializes the engine with the specified {@link AlgorithmParameterSpec}.
216 *
217 * @param paramSpec
218 * A {@link AlgorithmParameterSpec} to use.
219 * @throws InvalidParameterSpecException
220 * if <code>paramSpec</code> is invalid.
221 */
222 public final void init(AlgorithmParameterSpec paramSpec)
223 throws InvalidParameterSpecException
224 {
225 paramSpi.engineInit(paramSpec);
226 }
227
228 /**
229 * Initializes the engine with the specified parameters stored in the byte
230 * array and decodes them according to the ASN.1 specification. If the ASN.1
231 * specification exists then it succeeds otherwise an {@link IOException} is
232 * thrown.
233 *
234 * @param params
235 * the parameters to use.
236 * @throws IOException
237 * if a decoding error occurs.
238 */
239 public final void init(byte[]params) throws IOException
240 {
241 paramSpi.engineInit(params);
242 }
243
244 /**
245 * Initializes the engine with the specified parameters stored in the byte
246 * array and decodes them according to the specified decoding specification.
247 * If <code>format</code> is <code>null</code>, then this method decodes the
248 * byte array using the ASN.1 specification if it exists, otherwise it throws
249 * an {@link IOException}.
250 *
251 * @param params
252 * the parameters to use.
253 * @param format
254 * the name of decoding format to use.
255 * @throws IOException
256 * if a decoding error occurs.
257 */
258 public final void init(byte[]params, String format) throws IOException
259 {
260 paramSpi.engineInit(params, format);
261 }
262
263 /**
264 * Returns a new instance of <code>AlgorithmParameters</code> as a
265 * designated parameter specification {@link Class}.
266 *
267 * @param paramSpec
268 * the {@link Class} to use.
269 * @return the parameter specification.
270 * @throws InvalidParameterSpecException
271 * if <code>paramSpec</code> is invalid.
272 */
273 public final <T extends AlgorithmParameterSpec>
274 T getParameterSpec(Class<T> paramSpec)
275 throws InvalidParameterSpecException
276 {
277 return paramSpi.engineGetParameterSpec(paramSpec);
278 }
279
280 /**
281 * Returns the parameters in the default encoding format. The primary encoding
282 * format is ASN.1 if it exists for the specified type.
283 *
284 * @return byte array representing the parameters.
285 */
286 public final byte[] getEncoded() throws IOException
287 {
288 return paramSpi.engineGetEncoded();
289 }
290
291 /**
292 * Returns the parameters in the specified encoding format. If
293 * <code>format</code> is <code>null</code> then the ASN.1 encoding
294 * format is used if it exists for the specified type.
295 *
296 * @param format
297 * the name of the encoding format to use.
298 * @return the parameters encoded using the specified encoding scheme.
299 * @throws IOException
300 * if an encoding exception occurs, or if this parameter object has
301 * not been initialized.
302 */
303 public final byte[] getEncoded(String format) throws IOException
304 {
305 return paramSpi.engineGetEncoded(format);
306 }
307
308 /**
309 * Returns a string representation of the encoded form.
310 *
311 * @return a string representation of the encoded form.
312 */
313 public final String toString()
314 {
315 return paramSpi.engineToString();
316 }
317 }