Source for java.security.AlgorithmParameters

   1: /* AlgorithmParameters.java --- Algorithm Parameters Implementation Class
   2:    Copyright (C) 1999, 2003, 2004  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.security;
  40: 
  41: import gnu.java.lang.CPStringBuilder;
  42: 
  43: import gnu.java.security.Engine;
  44: 
  45: import java.io.IOException;
  46: import java.lang.reflect.InvocationTargetException;
  47: import java.security.spec.AlgorithmParameterSpec;
  48: import java.security.spec.InvalidParameterSpecException;
  49: 
  50: /**
  51:  * <code>AlgorithmParameters</code> is an Algorithm Parameters class which
  52:  * provides an interface through which the user can manage the parameters of an
  53:  * Algorithm.
  54:  *
  55:  * @author Mark Benvenuto
  56:  * @since 1.2
  57:  * @see AlgorithmParameterSpec
  58:  * @see java.security.spec.DSAParameterSpec
  59:  * @see KeyPairGenerator
  60:  */
  61: public class AlgorithmParameters
  62: {
  63:   /** Service name for algorithm parameters. */
  64:   private static final String ALGORITHM_PARAMETERS = "AlgorithmParameters";
  65: 
  66:   private AlgorithmParametersSpi paramSpi;
  67:   private Provider provider;
  68:   private String algorithm;
  69: 
  70:   /**
  71:    * Constructs a new instance of <code>AlgorithmParameters</code>.
  72:    *
  73:    * @param paramSpi
  74:    *          the engine to use.
  75:    * @param provider
  76:    *          the provider to use.
  77:    * @param algorithm
  78:    *          the algorithm to use.
  79:    */
  80:   protected AlgorithmParameters(AlgorithmParametersSpi paramSpi,
  81:                                 Provider provider, String algorithm)
  82:   {
  83:     this.paramSpi = paramSpi;
  84:     this.provider = provider;
  85:     this.algorithm = algorithm;
  86:   }
  87: 
  88:   /** @return A string with the name of the algorithm used. */
  89:   public final String getAlgorithm()
  90:   {
  91:     return algorithm;
  92:   }
  93: 
  94:   /**
  95:    * Returns a new instance of <code>AlgorithmParameters</code> representing
  96:    * the specified algorithm parameters.
  97:    * <p>
  98:    * The returned <code>AlgorithmParameters</code> must still be initialized
  99:    * 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: }