1 /*
   2  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.security;
  27 
  28 import java.io.*;
  29 import java.security.cert.Certificate;
  30 import java.security.cert.CertPath;
  31 import java.security.cert.X509Extension;
  32 import java.util.Date;
  33 import java.util.List;
  34 
  35 /**
  36  * This class encapsulates information about a signed timestamp.
  37  * It is immutable.
  38  * It includes the timestamp's date and time as well as information about the
  39  * Timestamping Authority (TSA) which generated and signed the timestamp.
  40  *
  41  * @since 1.5
  42  * @author Vincent Ryan
  43  */
  44 
  45 public final class Timestamp implements Serializable {
  46 
  47     private static final long serialVersionUID = -5502683707821851294L;
  48 
  49     /**
  50      * The timestamp's date and time
  51      *
  52      * @serial
  53      */
  54     private Date timestamp;
  55 
  56     /**
  57      * The TSA's certificate path.
  58      *
  59      * @serial
  60      */
  61     private CertPath signerCertPath;
  62 
  63     /*
  64      * Hash code for this timestamp.
  65      */
  66     private transient int myhash = -1;
  67 
  68     /**
  69      * Constructs a Timestamp.
  70      *
  71      * @param timestamp is the timestamp's date and time. It must not be null.
  72      * @param signerCertPath is the TSA's certificate path. It must not be null.
  73      * @throws NullPointerException if timestamp or signerCertPath is null.
  74      */
  75     public Timestamp(Date timestamp, CertPath signerCertPath) {
  76         if (timestamp == null || signerCertPath == null) {
  77             throw new NullPointerException();
  78         }
  79         this.timestamp = new Date(timestamp.getTime()); // clone
  80         this.signerCertPath = signerCertPath;
  81     }
  82 
  83     /**
  84      * Returns the date and time when the timestamp was generated.
  85      *
  86      * @return The timestamp's date and time.
  87      */
  88     public Date getTimestamp() {
  89         return new Date(timestamp.getTime()); // clone
  90     }
  91 
  92     /**
  93      * Returns the certificate path for the Timestamping Authority.
  94      *
  95      * @return The TSA's certificate path.
  96      */
  97     public CertPath getSignerCertPath() {
  98         return signerCertPath;
  99     }
 100 
 101     /**
 102      * Returns the hash code value for this timestamp.
 103      * The hash code is generated using the date and time of the timestamp
 104      * and the TSA's certificate path.
 105      *
 106      * @return a hash code value for this timestamp.
 107      */
 108     public int hashCode() {
 109         if (myhash == -1) {
 110             myhash = timestamp.hashCode() + signerCertPath.hashCode();
 111         }
 112         return myhash;
 113     }
 114 
 115     /**
 116      * Tests for equality between the specified object and this
 117      * timestamp. Two timestamps are considered equal if the date and time of
 118      * their timestamp's and their signer's certificate paths are equal.
 119      *
 120      * @param obj the object to test for equality with this timestamp.
 121      *
 122      * @return true if the timestamp are considered equal, false otherwise.
 123      */
 124     public boolean equals(Object obj) {
 125         if (obj == null || (!(obj instanceof Timestamp))) {
 126             return false;
 127         }
 128         Timestamp that = (Timestamp)obj;
 129 
 130         if (this == that) {
 131             return true;
 132         }
 133         return (timestamp.equals(that.getTimestamp()) &&
 134             signerCertPath.equals(that.getSignerCertPath()));
 135     }
 136 
 137     /**
 138      * Returns a string describing this timestamp.
 139      *
 140      * @return A string comprising the date and time of the timestamp and
 141      *         its signer's certificate.
 142      */
 143     public String toString() {
 144         StringBuilder sb = new StringBuilder();
 145         sb.append("(");
 146         sb.append("timestamp: " + timestamp);
 147         List<? extends Certificate> certs = signerCertPath.getCertificates();
 148         if (!certs.isEmpty()) {
 149             sb.append("TSA: " + certs.get(0));
 150         } else {
 151             sb.append("TSA: <empty>");
 152         }
 153         sb.append(")");
 154         return sb.toString();
 155     }
 156 
 157     // Explicitly reset hash code value to -1
 158     private void readObject(ObjectInputStream ois)
 159         throws IOException, ClassNotFoundException {
 160         ois.defaultReadObject();
 161         myhash = -1;
 162         timestamp = new Date(timestamp.getTime());
 163     }
 164 }