Source for java.security.cert.CertPath

   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., 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: 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<String> 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<? extends Certificate> 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