ResponseAPDU Class Reference

Description

Encapsulation of a smartcard response Application Protocol Data Unit (APDU)

The response APDU is the communication message sent from a smartcard to a card reader. This class encapsulates a response APDU, ensuring its validity at construction-time, and guaranteeing it remains valid for the lifetime of the object. The get() method provides read-only access to the raw APDU data.

Additional information may be found at: https://en.wikipedia.org/wiki/Smart_card_application_protocol_data_unit

The full specification of the format is defined in ISO/IEC 7816-3 and ISO/IEC 7816-4.

Invariant

Stored fields are all within range for the APDU format.

Thread safety: This class is immutable, and thus fully thread-safe post-construction.

See also

CommandAPDU for the command equivalent, and SmartcardAPI for related functionality

Public Member Functions
	ResponseAPDU ()
	Construct an empty APDU - no response data, and status set to 0x6F00. More...
	ResponseAPDU (@NonNull byte[] data, int SW1, int SW2)
	Create an APDU containing given data and status values. More...
	ResponseAPDU (@NonNull byte[] stream)
	Extract APDU data from a byte stream. More...
byte []	get ()
	Copy the entire APDU in byte-array format. More...
String	hexDump ()
	Obtain a hex dump of the entire APDU. More...
byte []	responseData ()
	Copy the response data field, if present. More...
int	responseDataSize ()
	Query the size in bytes of the response (excluding SW1 and SW2)
String	statusString ()
	Description of the status value stored in fields SW1 and SW2. More...
boolean	successComplete ()
	Return whether the response indicates successful processing of the command with no further data remaining. More...
boolean	successIncomplete ()
	Return whether the response indicates successful processing of the command, but there is more data remaining. More...
short	SW1 ()
	Query the first command processing status byte (SW1) More...
short	SW2 ()
	Query the second command processing status byte (SW2) More...

Static Public Member Functions
static String	statusString (int SW1, int SW2)
	String description of a given response status. More...

Static Public Attributes
static final int	MaxResponseLength
	Maximum permitted response length (excluding status bytes)

Constructor & Destructor Documentation

ResponseAPDU() [1/3]

ResponseAPDU

(

)

Construct an empty APDU - no response data, and status set to 0x6F00.

This constructor should only be used when it is necessary to return a sentinel value, and that some other indication (e.g. an error code parameter) is supplied to a user to notify them that the value is invalid.

ResponseAPDU() [2/3]

ResponseAPDU	(	@NonNull byte []	data,
		int	SW1,
		int	SW2
	)

Create an APDU containing given data and status values.

Parameters

data	Response data; length must not exceed MaxResponseLength
SW1	First status byte - e.g. 0x90 for success. Valid ranges are 0x61-0x6F and 0x90-0x9F.
SW2	Second status byte - e.g. 0x00 for success. Valid range is 0-255.

Exceptions

IllegalArgumentException

if SW1 or SW2 are out of range, or if data is too long

ResponseAPDU() [3/3]

ResponseAPDU

(

@NonNull byte []

stream

)

Extract APDU data from a byte stream.

The last two bytes in the array are used to construct the SW1 and SW2 fields; the remainder is treated as response data.

Parameters

stream

APDU data stream; length must be at least 2 bytes, and at most MaxResponseLength + 2

Exceptions

IllegalArgumentException

if data length is illegal, or if the second-last byte holds an invalid value for SW1

Member Function Documentation

get()

byte [] get

(

)

Copy the entire APDU in byte-array format.

Returns

Entire APDU, including data, SW1 and SW2 fields

hexDump()

String hexDump

(

)

Obtain a hex dump of the entire APDU.

Returns

Hex dump with spaces separating the bytes

responseData()

byte [] responseData

(

)

Copy the response data field, if present.

Returns

Response data (length 1-65535 bytes) if present, otherwise a zero-length array

statusString() [1/2]

String statusString

(

)

Description of the status value stored in fields SW1 and SW2.

Returns

String containing a textual description of the response status

statusString() [2/2]

static String statusString ( int  SW1, int  SW2  )

static

String description of a given response status.

Parameters

SW1	First status byte, valid ranges 0x61-0x6F and 0x90-0x9F
SW2	Second status byte, valid range 0-255

Returns

String containing a textual description of the status value stored in the supplied parameters

Exceptions

IllegalArgumentException

if either of the parameters are out of range

successComplete()

boolean successComplete

(

)

Return whether the response indicates successful processing of the command with no further data remaining.

Returns

True for status 0x9000, false otherwise

successIncomplete()

boolean successIncomplete

(

)

Return whether the response indicates successful processing of the command, but there is more data remaining.

Returns

True for status 0x6100-0x61FF (inclusive), false otherwise

SW1()

short SW1

(

)

Query the first command processing status byte (SW1)

Returns

SW1 byte - e.g. 0x90 for success with no further data remaining; valid ranges are 0x61-0x6F and 0x90-0x9F inclusive

SW2()

short SW2

(

)

Query the second command processing status byte (SW2)

Returns

SW2 byte - e.g. 0x90 for success with no further data remaining; valid ranges are 0x61-0x6F and 0x90-0x9F inclusive