Source for gnu.java.security.hash.HashFactory

   1: /* HashFactory.java --
   2:    Copyright (C) 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.hash;
  40: 
  41: import gnu.java.security.Registry;
  42: 
  43: import java.util.Collections;
  44: import java.util.HashSet;
  45: import java.util.Set;
  46: 
  47: /**
  48:  * A <i>Factory</i> to instantiate message digest algorithm instances.
  49:  */
  50: public class HashFactory
  51: {
  52:   /** Trivial constructor to enforce <i>Singleton</i> pattern. */
  53:   private HashFactory()
  54:   {
  55:     super();
  56:   }
  57: 
  58:   /**
  59:    * Return an instance of a hash algorithm given its name.
  60:    *
  61:    * @param name the name of the hash algorithm.
  62:    * @return an instance of the hash algorithm, or null if none found.
  63:    * @exception InternalError if the implementation does not pass its self-
  64:    *              test.
  65:    */
  66:   public static IMessageDigest getInstance(String name)
  67:   {
  68:     if (name == null)
  69:       return null;
  70: 
  71:     name = name.trim();
  72:     IMessageDigest result = null;
  73:     if (name.equalsIgnoreCase(Registry.WHIRLPOOL_HASH))
  74:       result = new Whirlpool();
  75:     else if (name.equalsIgnoreCase(Registry.RIPEMD128_HASH)
  76:              || name.equalsIgnoreCase(Registry.RIPEMD_128_HASH))
  77:       result = new RipeMD128();
  78:     else if (name.equalsIgnoreCase(Registry.RIPEMD160_HASH)
  79:              || name.equalsIgnoreCase(Registry.RIPEMD_160_HASH))
  80:       result = new RipeMD160();
  81:     else if (name.equalsIgnoreCase(Registry.SHA160_HASH)
  82:              || name.equalsIgnoreCase(Registry.SHA_1_HASH)
  83:              || name.equalsIgnoreCase(Registry.SHA1_HASH)
  84:              || name.equalsIgnoreCase(Registry.SHA_HASH))
  85:       result = new Sha160();
  86:     else if (name.equalsIgnoreCase(Registry.SHA256_HASH))
  87:       result = new Sha256();
  88:     else if (name.equalsIgnoreCase(Registry.SHA384_HASH))
  89:       result = new Sha384();
  90:     else if (name.equalsIgnoreCase(Registry.SHA512_HASH))
  91:       result = new Sha512();
  92:     else if (name.equalsIgnoreCase(Registry.TIGER_HASH))
  93:       result = new Tiger();
  94:     else if (name.equalsIgnoreCase(Registry.HAVAL_HASH))
  95:       result = new Haval();
  96:     else if (name.equalsIgnoreCase(Registry.MD5_HASH))
  97:       result = new MD5();
  98:     else if (name.equalsIgnoreCase(Registry.MD4_HASH))
  99:       result = new MD4();
 100:     else if (name.equalsIgnoreCase(Registry.MD2_HASH))
 101:       result = new MD2();
 102:     else if (name.equalsIgnoreCase(Registry.HAVAL_HASH))
 103:       result = new Haval();
 104: 
 105:     if (result != null && ! result.selfTest())
 106:       throw new InternalError(result.name());
 107: 
 108:     return result;
 109:   }
 110: 
 111:   /**
 112:    * Returns a {@link Set} of names of hash algorithms supported by this
 113:    * <i>Factory</i>.
 114:    *
 115:    * @return a {@link Set} of hash names (Strings).
 116:    */
 117:   public static final Set getNames()
 118:   {
 119:     HashSet hs = new HashSet();
 120:     hs.add(Registry.WHIRLPOOL_HASH);
 121:     hs.add(Registry.RIPEMD128_HASH);
 122:     hs.add(Registry.RIPEMD160_HASH);
 123:     hs.add(Registry.SHA160_HASH);
 124:     hs.add(Registry.SHA256_HASH);
 125:     hs.add(Registry.SHA384_HASH);
 126:     hs.add(Registry.SHA512_HASH);
 127:     hs.add(Registry.TIGER_HASH);
 128:     hs.add(Registry.HAVAL_HASH);
 129:     hs.add(Registry.MD5_HASH);
 130:     hs.add(Registry.MD4_HASH);
 131:     hs.add(Registry.MD2_HASH);
 132: 
 133:     return Collections.unmodifiableSet(hs);
 134:   }
 135: }