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package javax.smartcardio;

import java.util.Arrays;

A response APDU as defined in ISO/IEC 7816-4. It consists of a conditional body and a two byte trailer. This class does not attempt to verify that the APDU encodes a semantically valid response.

Instances of this class are immutable. Where data is passed in or out via byte arrays, defensive cloning is performed.

Author: Andreas Sterbenz, JSR 268 Expert Group
See Also:
Since: 1.6
/** * A response APDU as defined in ISO/IEC 7816-4. It consists of a conditional * body and a two byte trailer. * This class does not attempt to verify that the APDU encodes a semantically * valid response. * * <p>Instances of this class are immutable. Where data is passed in or out * via byte arrays, defensive cloning is performed. * * @see CommandAPDU * @see CardChannel#transmit CardChannel.transmit * * @since 1.6 * @author Andreas Sterbenz * @author JSR 268 Expert Group */
public final class ResponseAPDU implements java.io.Serializable { private static final long serialVersionUID = 6962744978375594225L;
@serial
/** @serial */
private byte[] apdu;
Constructs a ResponseAPDU from a byte array containing the complete APDU contents (conditional body and trailed).

Note that the byte array is cloned to protect against subsequent modification.

Params:
  • apdu – the complete response APDU
Throws:
/** * Constructs a ResponseAPDU from a byte array containing the complete * APDU contents (conditional body and trailed). * * <p>Note that the byte array is cloned to protect against subsequent * modification. * * @param apdu the complete response APDU * * @throws NullPointerException if apdu is null * @throws IllegalArgumentException if apdu.length is less than 2 */
public ResponseAPDU(byte[] apdu) { apdu = apdu.clone(); check(apdu); this.apdu = apdu; } private static void check(byte[] apdu) { if (apdu.length < 2) { throw new IllegalArgumentException("apdu must be at least 2 bytes long"); } }
Returns the number of data bytes in the response body (Nr) or 0 if this APDU has no body. This call is equivalent to getData().length.
Returns:the number of data bytes in the response body or 0 if this APDU has no body.
/** * Returns the number of data bytes in the response body (Nr) or 0 if this * APDU has no body. This call is equivalent to * <code>getData().length</code>. * * @return the number of data bytes in the response body or 0 if this APDU * has no body. */
public int getNr() { return apdu.length - 2; }
Returns a copy of the data bytes in the response body. If this APDU as no body, this method returns a byte array with a length of zero.
Returns:a copy of the data bytes in the response body or the empty byte array if this APDU has no body.
/** * Returns a copy of the data bytes in the response body. If this APDU as * no body, this method returns a byte array with a length of zero. * * @return a copy of the data bytes in the response body or the empty * byte array if this APDU has no body. */
public byte[] getData() { byte[] data = new byte[apdu.length - 2]; System.arraycopy(apdu, 0, data, 0, data.length); return data; }
Returns the value of the status byte SW1 as a value between 0 and 255.
Returns:the value of the status byte SW1 as a value between 0 and 255.
/** * Returns the value of the status byte SW1 as a value between 0 and 255. * * @return the value of the status byte SW1 as a value between 0 and 255. */
public int getSW1() { return apdu[apdu.length - 2] & 0xff; }
Returns the value of the status byte SW2 as a value between 0 and 255.
Returns:the value of the status byte SW2 as a value between 0 and 255.
/** * Returns the value of the status byte SW2 as a value between 0 and 255. * * @return the value of the status byte SW2 as a value between 0 and 255. */
public int getSW2() { return apdu[apdu.length - 1] & 0xff; }
Returns the value of the status bytes SW1 and SW2 as a single status word SW. It is defined as (getSW1() << 8) | getSW2()
Returns:the value of the status word SW.
/** * Returns the value of the status bytes SW1 and SW2 as a single * status word SW. * It is defined as * {@code (getSW1() << 8) | getSW2()} * * @return the value of the status word SW. */
public int getSW() { return (getSW1() << 8) | getSW2(); }
Returns a copy of the bytes in this APDU.
Returns:a copy of the bytes in this APDU.
/** * Returns a copy of the bytes in this APDU. * * @return a copy of the bytes in this APDU. */
public byte[] getBytes() { return apdu.clone(); }
Returns a string representation of this response APDU.
Returns:a String representation of this response APDU.
/** * Returns a string representation of this response APDU. * * @return a String representation of this response APDU. */
public String toString() { return "ResponseAPDU: " + apdu.length + " bytes, SW=" + Integer.toHexString(getSW()); }
Compares the specified object with this response APDU for equality. Returns true if the given object is also a ResponseAPDU and its bytes are identical to the bytes in this ResponseAPDU.
Params:
  • obj – the object to be compared for equality with this response APDU
Returns:true if the specified object is equal to this response APDU
/** * Compares the specified object with this response APDU for equality. * Returns true if the given object is also a ResponseAPDU and its bytes are * identical to the bytes in this ResponseAPDU. * * @param obj the object to be compared for equality with this response APDU * @return true if the specified object is equal to this response APDU */
public boolean equals(Object obj) { if (this == obj) { return true; } if (obj instanceof ResponseAPDU == false) { return false; } ResponseAPDU other = (ResponseAPDU)obj; return Arrays.equals(this.apdu, other.apdu); }
Returns the hash code value for this response APDU.
Returns:the hash code value for this response APDU.
/** * Returns the hash code value for this response APDU. * * @return the hash code value for this response APDU. */
public int hashCode() { return Arrays.hashCode(apdu); } private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException { apdu = (byte[])in.readUnshared(); check(apdu); } }