001 /* CertPath.java -- a sequence of certificates
002 Copyright (C) 2002, 2005 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package java.security.cert;
039
040 import java.io.ByteArrayInputStream;
041 import java.io.NotSerializableException;
042 import java.io.ObjectStreamException;
043 import java.io.Serializable;
044 import java.util.Iterator;
045 import java.util.List;
046
047 /**
048 * This class represents an immutable sequence, or path, of security
049 * certificates. The path type must match the type of each certificate in the
050 * path, or in other words, for all instances of cert in a certpath object,
051 * <code>cert.getType().equals(certpath.getType())</code> will return true.
052 *
053 * <p>Since this class is immutable, it is thread-safe. During serialization,
054 * the path is consolidated into a {@link CertPathRep}, which preserves the
055 * data regardless of the underlying implementation of the path.
056 *
057 * @author Eric Blake (ebb9@email.byu.edu)
058 * @since 1.4
059 * @status updated to 1.4
060 */
061 public abstract class CertPath implements Serializable
062 {
063 /**
064 * The serialized representation of a path.
065 *
066 * @author Eric Blake (ebb9@email.byu.edu)
067 */
068 protected static class CertPathRep implements Serializable
069 {
070 /**
071 * Compatible with JDK 1.4+.
072 */
073 private static final long serialVersionUID = 3015633072427920915L;
074
075 /**
076 * The certificate type.
077 *
078 * @serial the type of the certificate path
079 */
080 private final String type;
081
082 /**
083 * The encoded form of the path.
084 *
085 * @serial the encoded form
086 */
087 private final byte[] data;
088
089 /**
090 * Create the new serial representation.
091 *
092 * @param type the path type
093 * @param data the encoded path data
094 */
095 protected CertPathRep(String type, byte[] data)
096 {
097 this.type = type;
098 this.data = data;
099 }
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