1 /* 2 * Copyright (c) 2005, 2013, 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 javax.smartcardio; 27 28 import java.util.Arrays; 29 30 /** 31 * A response APDU as defined in ISO/IEC 7816-4. It consists of a conditional 32 * body and a two byte trailer. 33 * This class does not attempt to verify that the APDU encodes a semantically 34 * valid response. 35 * 36 * <p>Instances of this class are immutable. Where data is passed in or out 37 * via byte arrays, defensive cloning is performed. 38 * 39 * @see CommandAPDU 40 * @see CardChannel#transmit CardChannel.transmit 41 * 42 * @since 1.6 43 * @author Andreas Sterbenz 44 * @author JSR 268 Expert Group 45 */ 46 public final class ResponseAPDU implements java.io.Serializable { 47 48 private static final long serialVersionUID = 6962744978375594225L; 49 50 /** @serial */ 51 private byte[] apdu; 52 53 /** 54 * Constructs a ResponseAPDU from a byte array containing the complete 55 * APDU contents (conditional body and trailed). 56 * 57 * <p>Note that the byte array is cloned to protect against subsequent 58 * modification. 59 * 60 * @param apdu the complete response APDU 61 * 62 * @throws NullPointerException if apdu is null 63 * @throws IllegalArgumentException if apdu.length is less than 2 64 */ ResponseAPDU(byte[] apdu)65 public ResponseAPDU(byte[] apdu) { 66 apdu = apdu.clone(); 67 check(apdu); 68 this.apdu = apdu; 69 } 70 check(byte[] apdu)71 private static void check(byte[] apdu) { 72 if (apdu.length < 2) { 73 throw new IllegalArgumentException("apdu must be at least 2 bytes long"); 74 } 75 } 76 77 /** 78 * Returns the number of data bytes in the response body (Nr) or 0 if this 79 * APDU has no body. This call is equivalent to 80 * <code>getData().length</code>. 81 * 82 * @return the number of data bytes in the response body or 0 if this APDU 83 * has no body. 84 */ getNr()85 public int getNr() { 86 return apdu.length - 2; 87 } 88 89 /** 90 * Returns a copy of the data bytes in the response body. If this APDU as 91 * no body, this method returns a byte array with a length of zero. 92 * 93 * @return a copy of the data bytes in the response body or the empty 94 * byte array if this APDU has no body. 95 */ getData()96 public byte[] getData() { 97 byte[] data = new byte[apdu.length - 2]; 98 System.arraycopy(apdu, 0, data, 0, data.length); 99 return data; 100 } 101 102 /** 103 * Returns the value of the status byte SW1 as a value between 0 and 255. 104 * 105 * @return the value of the status byte SW1 as a value between 0 and 255. 106 */ getSW1()107 public int getSW1() { 108 return apdu[apdu.length - 2] & 0xff; 109 } 110 111 /** 112 * Returns the value of the status byte SW2 as a value between 0 and 255. 113 * 114 * @return the value of the status byte SW2 as a value between 0 and 255. 115 */ getSW2()116 public int getSW2() { 117 return apdu[apdu.length - 1] & 0xff; 118 } 119 120 /** 121 * Returns the value of the status bytes SW1 and SW2 as a single 122 * status word SW. 123 * It is defined as 124 * {@code (getSW1() << 8) | getSW2()} 125 * 126 * @return the value of the status word SW. 127 */ getSW()128 public int getSW() { 129 return (getSW1() << 8) | getSW2(); 130 } 131 132 /** 133 * Returns a copy of the bytes in this APDU. 134 * 135 * @return a copy of the bytes in this APDU. 136 */ getBytes()137 public byte[] getBytes() { 138 return apdu.clone(); 139 } 140 141 /** 142 * Returns a string representation of this response APDU. 143 * 144 * @return a String representation of this response APDU. 145 */ toString()146 public String toString() { 147 return "ResponseAPDU: " + apdu.length + " bytes, SW=" 148 + Integer.toHexString(getSW()); 149 } 150 151 /** 152 * Compares the specified object with this response APDU for equality. 153 * Returns true if the given object is also a ResponseAPDU and its bytes are 154 * identical to the bytes in this ResponseAPDU. 155 * 156 * @param obj the object to be compared for equality with this response APDU 157 * @return true if the specified object is equal to this response APDU 158 */ equals(Object obj)159 public boolean equals(Object obj) { 160 if (this == obj) { 161 return true; 162 } 163 if (obj instanceof ResponseAPDU == false) { 164 return false; 165 } 166 ResponseAPDU other = (ResponseAPDU)obj; 167 return Arrays.equals(this.apdu, other.apdu); 168 } 169 170 /** 171 * Returns the hash code value for this response APDU. 172 * 173 * @return the hash code value for this response APDU. 174 */ hashCode()175 public int hashCode() { 176 return Arrays.hashCode(apdu); 177 } 178 readObject(java.io.ObjectInputStream in)179 private void readObject(java.io.ObjectInputStream in) 180 throws java.io.IOException, ClassNotFoundException { 181 apdu = (byte[])in.readUnshared(); 182 check(apdu); 183 } 184 185 } 186