libjava/classpath/gnu/javax/crypto/pad/PadFactory.java

   1 /* PadFactory.java --
   2    Copyright (C) 2001, 2002, 2003, 2004, 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.javax.crypto.pad;
  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  * <p>A Factory to instantiate padding schemes.</p>
  49  */
  50 public class PadFactory implements Registry
  51 {
  52
  53   // Constants and variables
  54   // -------------------------------------------------------------------------
  55
  56   // Constructor(s)
  57   // -------------------------------------------------------------------------
  58
  59   /** Trivial constructor to enforce Singleton pattern. */
  60   private PadFactory()
  61   {
  62     super();
  63   }
  64
  65   // Class methods
  66   // -------------------------------------------------------------------------
  67
  68   /**
  69    * <p>Returns an instance of a padding algorithm given its name.</p>
  70    *
  71    * @param pad the case-insensitive name of the padding algorithm.
  72    * @return an instance of the padding algorithm, operating with a given
  73    * block size, or <code>null</code> if none found.
  74    * @throws InternalError if the implementation does not pass its self-test.
  75    */
  76   public static final IPad getInstance(String pad)
  77   {
  78     if (pad == null)
  79       {
  80         return null;
  81       }
  82
  83     pad = pad.trim().toLowerCase();
  84     if (pad.endsWith("padding"))
  85       pad = pad.substring(0, pad.length() - "padding".length());
  86     IPad result = null;
  87     if (pad.equals(PKCS7_PAD) || pad.equals(PKCS5_PAD))
  88       {
  89         result = new PKCS7();
  90       }
  91     else if (pad.equals(TBC_PAD))
  92       {
  93         result = new TBC();
  94       }
  95     else if (pad.equals(EME_PKCS1_V1_5_PAD))
  96       {
  97         result = new PKCS1_V1_5();
  98       }
  99     else if (pad.equals(SSL3_PAD))
 100       {
 101         result = new SSL3();
 102       }
 103     else if (pad.equals(TLS1_PAD))
 104       {
 105         result = new TLS1();
 106       }
 107
 108     if (result != null && !result.selfTest())
 109       {
 110         throw new InternalError(result.name());
 111       }
 112
 113     return result;
 114   }
 115
 116   /**
 117    * <p>Returns a {@link java.util.Set} of names of padding algorithms
 118    * supported by this <i>Factory</i>.</p>
 119    *
 120    * @return a {@link Set} of padding algorithm names (Strings).
 121    */
 122   public static final Set getNames()
 123   {
 124     HashSet hs = new HashSet();
 125     hs.add(PKCS5_PAD);
 126     hs.add(PKCS7_PAD);
 127     hs.add(TBC_PAD);
 128     hs.add(EME_PKCS1_V1_5_PAD);
 129     hs.add(SSL3_PAD);
 130     hs.add(TLS1_PAD);
 131
 132     return Collections.unmodifiableSet(hs);
 133   }
 134
 135   // Instance methods
 136   // -------------------------------------------------------------------------
 137 }