001/* AlgorithmParameters.java --- Algorithm Parameters Implementation Class 002 Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package java.security; 040 041import gnu.java.lang.CPStringBuilder; 042 043import gnu.java.security.Engine; 044 045import java.io.IOException; 046import java.lang.reflect.InvocationTargetException; 047import java.security.spec.AlgorithmParameterSpec; 048import 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 */ 061public 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}