libjava/java/security/cert/CertPath.java

   1 /* CertPath.java -- a sequence of certificates
   2    Copyright (C) 2002, 2005  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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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 package java.security.cert;
  39
  40 import java.io.ByteArrayInputStream;
  41 import java.io.NotSerializableException;
  42 import java.io.ObjectStreamException;
  43 import java.io.Serializable;
  44 import java.util.Iterator;
  45 import java.util.List;
  46
  47 /**
  48  * This class represents an immutable sequence, or path, of security
  49  * certificates. The path type must match the type of each certificate in the
  50  * path, or in other words, for all instances of cert in a certpath object,
  51  * <code>cert.getType().equals(certpath.getType())</code> will return true.
  52  *
  53  * <p>Since this class is immutable, it is thread-safe. During serialization,
  54  * the path is consolidated into a {@link CertPathRep}, which preserves the
  55  * data regardless of the underlying implementation of the path.
  56  *
  57  * @author Eric Blake (ebb9@email.byu.edu)
  58  * @since 1.4
  59  * @status updated to 1.4
  60  */
  61 public abstract class CertPath implements Serializable
  62 {
  63   /**
  64    * The serialized representation of a path.
  65    *
  66    * @author Eric Blake (ebb9@email.byu.edu)
  67    */
  68   protected static class CertPathRep implements Serializable
  69   {
  70     /**
  71      * Compatible with JDK 1.4+.
  72      */
  73     private static final long serialVersionUID = 3015633072427920915L;
  74
  75     /**
  76      * The certificate type.
  77      *
  78      * @serial the type of the certificate path
  79      */
  80     private final String type;
  81
  82     /**
  83      * The encoded form of the path.
  84      *
  85      * @serial the encoded form
  86      */
  87     private final byte[] data;
  88
  89     /**
  90      * Create the new serial representation.
  91      *
  92      * @param type the path type
  93      * @param data the encoded path data
  94      */
  95     protected CertPathRep(String type, byte[] data)
  96     {
  97       this.type = type;
  98       this.data = data;
  99     }
 100
 101     /**
 102      * Decode the data into an actual {@link CertPath} upon deserialization.
 103      *
 104      * @return the replacement object
 105      * @throws ObjectStreamException if replacement fails
 106      */
 107     protected Object readResolve() throws ObjectStreamException
 108     {
 109       try
 110         {
 111           return CertificateFactory.getInstance(type)
 112             .generateCertPath(new ByteArrayInputStream(data));
 113         }
 114       catch (CertificateException e)
 115         {
 116           throw (ObjectStreamException)
 117             new NotSerializableException("java.security.cert.CertPath: "
 118                                          + type).initCause(e);
 119         }
 120     }
 121   } // class CertPathRep
 122
 123   /**
 124    * Compatible with JDK 1.4+.
 125    */
 126   private static final long serialVersionUID = 6068470306649138683L;
 127
 128   /**
 129    * The path type.
 130    *
 131    * @serial the type of all certificates in this path
 132    */
 133   private final String type;
 134
 135   /**
 136    * Create a certificate path with the given type. Most code should use
 137    * {@link CertificateFactory} to create CertPaths.
 138    *
 139    * @param type the type of the path
 140    */
 141   protected CertPath(String type)
 142   {
 143     this.type = type;
 144   }
 145
 146   /**
 147    * Get the (non-null) type of all certificates in the path.
 148    *
 149    * @return the path certificate type
 150    */
 151   public String getType()
 152   {
 153     return type;
 154   }
 155
 156   /**
 157    * Get an immutable iterator over the path encodings (all String names),
 158    * starting with the default encoding. The iterator will throw an
 159    * <code>UnsupportedOperationException</code> if an attempt is made to
 160    * remove items from the list.
 161    *
 162    * @return the iterator of supported encodings in the path
 163    */
 164   public abstract Iterator getEncodings();
 165
 166   /**
 167    * Compares this path to another for semantic equality. To be equal, both
 168    * must be instances of CertPath, with the same type, and identical
 169    * certificate lists. Overriding classes must not change this behavior.
 170    *
 171    * @param o the object to compare to
 172    * @return true if the two are equal
 173    */
 174   public boolean equals(Object o)
 175   {
 176     if (! (o instanceof CertPath))
 177       return false;
 178     CertPath cp = (CertPath) o;
 179     return type.equals(cp.type)
 180       && getCertificates().equals(cp.getCertificates());
 181   }
 182
 183   /**
 184    * Returns the hashcode of this certificate path. This is defined as:<br>
 185    * <code>31 * getType().hashCode() + getCertificates().hashCode()</code>.
 186    *
 187    * @return the hashcode
 188    */
 189   public int hashCode()
 190   {
 191     return 31 * type.hashCode() + getCertificates().hashCode();
 192   }
 193
 194   public String toString()
 195   {
 196     List l = getCertificates();
 197     int size = l.size();
 198     int i = 0;
 199     StringBuffer result = new StringBuffer(type);
 200     result.append(" Cert Path: length = ").append(size).append(".\n[\n");
 201     while (--size >= 0)
 202       result.append(l.get(i++)).append('\n');
 203     return result.append("\n]").toString();
 204   }
 205
 206   /**
 207    * Returns the encoded form of this path, via the default encoding.
 208    *
 209    * @return the encoded form
 210    * @throws CertificateEncodingException if encoding fails
 211    */
 212   public abstract byte[] getEncoded() throws CertificateEncodingException;
 213
 214   /**
 215    * Returns the encoded form of this path, via the specified encoding.
 216    *
 217    * @param encoding the encoding to use
 218    * @return the encoded form
 219    * @throws CertificateEncodingException if encoding fails or does not exist
 220    */
 221   public abstract byte[] getEncoded(String encoding)
 222     throws CertificateEncodingException;
 223
 224   /**
 225    * Returns the immutable, thread-safe list of certificates in this path.
 226    *
 227    * @return the list of certificates, non-null but possibly empty
 228    */
 229   public abstract List getCertificates();
 230
 231   /**
 232    * Serializes the path in its encoded form, to ensure reserialization with
 233    * the appropriate factory object without worrying about list implementation.
 234    * The result will always be an instance of {@link CertPathRep}.
 235    *
 236    * @return the replacement object
 237    * @throws ObjectStreamException if the replacement creation fails
 238    */
 239   protected Object writeReplace() throws ObjectStreamException
 240   {
 241     try
 242       {
 243         return new CertPathRep(type, getEncoded());
 244       }
 245     catch (CertificateEncodingException e)
 246       {
 247         throw (ObjectStreamException)
 248           new NotSerializableException("java.security.cert.CertPath: "
 249                                        + type).initCause(e);
 250       }
 251   }
 252 } // class CertPath