Source for gnu.java.security.key.KeyPairGeneratorFactory

   1: /* KeyPairGeneratorFactory.java --
   2:    Copyright 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is a 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 of the License, or (at
   9: your option) 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; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: 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 gnu.java.security.key;
  40: 
  41: import gnu.java.security.Registry;
  42: import gnu.java.security.key.dss.DSSKeyPairGenerator;
  43: import gnu.java.security.key.rsa.RSAKeyPairGenerator;
  44: 
  45: import java.lang.reflect.Constructor;
  46: import java.util.Collections;
  47: import java.util.HashSet;
  48: import java.util.Set;
  49: 
  50: /**
  51:  * A Factory to instantiate asymmetric keypair generators.
  52:  */
  53: public class KeyPairGeneratorFactory
  54: {
  55:   /** Trivial constructor to enforce Singleton pattern. */
  56:   private KeyPairGeneratorFactory()
  57:   {
  58:     super();
  59:   }
  60: 
  61:   /**
  62:    * Returns an instance of a keypair generator given its name.
  63:    *
  64:    * @param name the case-insensitive key generator name.
  65:    * @return an instance of the keypair generator, or <code>null</code> if
  66:    *         none found.
  67:    */
  68:   public static IKeyPairGenerator getInstance(String name)
  69:   {
  70:     if (name == null)
  71:       return null;
  72: 
  73:     name = name.trim();
  74:     IKeyPairGenerator result = null;
  75:     if (name.equalsIgnoreCase(Registry.DSA_KPG)
  76:         || name.equalsIgnoreCase(Registry.DSS_KPG))
  77:       result = new DSSKeyPairGenerator();
  78:     else if (name.equalsIgnoreCase(Registry.RSA_KPG))
  79:       result = new RSAKeyPairGenerator();
  80:     else if (name.equalsIgnoreCase(Registry.DH_KPG))
  81:       result = makeInstance("gnu.javax.crypto.key.dh.GnuDHKeyPairGenerator");
  82:     else if (name.equalsIgnoreCase(Registry.SRP_KPG))
  83:       result = makeInstance("gnu.javax.crypto.key.srp6.SRPKeyPairGenerator");
  84: 
  85:     return result;
  86:   }
  87: 
  88:   /**
  89:    * Returns a {@link Set} of keypair generator names supported by this
  90:    * <i>Factory</i>. Those keypair generators may be used in conjunction with
  91:    * the digital signature schemes with appendix supported by this library.
  92:    *
  93:    * @return a {@link Set} of keypair generator names (Strings).
  94:    */
  95:   public static final Set getNames()
  96:   {
  97:     HashSet hs = new HashSet();
  98:     hs.add(Registry.DSS_KPG);
  99:     hs.add(Registry.DSA_KPG);
 100:     hs.add(Registry.RSA_KPG);
 101:     hs.add(Registry.DH_KPG);
 102:     hs.add(Registry.SRP_KPG);
 103:     return Collections.unmodifiableSet(hs);
 104:   }
 105: 
 106:   private static IKeyPairGenerator makeInstance(String clazz)
 107:   {
 108:     try
 109:       {
 110:         Class c = Class.forName(clazz);
 111:         Constructor ctor = c.getConstructor(new Class[0]);
 112:         return (IKeyPairGenerator) ctor.newInstance(new Object[0]);
 113:       }
 114:     catch (Exception x)
 115:       {
 116:         throw new IllegalArgumentException(
 117:             "strong crypto key pair generator not available: " + clazz, x);
 118:       }
 119:   }
 120: }