tuwien.auto.calimero.link.medium
Class PL132Ack

java.lang.Object
  tuwien.auto.calimero.link.medium.RawAckBase
      tuwien.auto.calimero.link.medium.PL132Ack

All Implemented Interfaces:

RawFrame

public class PL132Ack
extends RawAckBase

Raw acknowledge frame on PL132 communication medium.

The acknowledge on PL132 medium is handled using the frame checksum in the associated frame request.
A positive acknowledgment frame contains the sequence of bits received in the FCS field of the associated L-data request. A negative acknowledgment contains the bitwise complement of the checksum received with the L-data request.

Field Summary

static int	FULL Negative acknowledge type, reception buffer is full.
static int	UNKNOWN_ACK The kind of acknowledge is unknown, because no checksum from the frame request is available for comparison, or the delivered checksum in the ack-frame is invalid.

Fields inherited from class tuwien.auto.calimero.link.medium.RawAckBase

ack, ACK, NAK

Fields inherited from interface tuwien.auto.calimero.link.medium.RawFrame

ACK_FRAME, LDATA_FRAME, LPOLLDATA_FRAME

Constructor Summary

PL132Ack(byte[] data, int offset)
Creates a new PL132 acknowledge frame out of a byte array.

PL132Ack(byte[] data, int offset, int requestChecksum)
Creates a new PL132 acknowledge frame out of a byte array.

Method Summary

int	getChecksum() Returns the checksum contained in this acknowledge frame.
java.lang.String	toString() Returns a textual representation of the acknowledge frame information.

Methods inherited from class tuwien.auto.calimero.link.medium.RawAckBase

getAckType, getFrameType

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

FULL

public static final int FULL

Negative acknowledge type, reception buffer is full.

See Also:

RawAckBase.getAckType(), Constant Field Values

UNKNOWN_ACK

public static final int UNKNOWN_ACK

The kind of acknowledge is unknown, because no checksum from the frame request is available for comparison, or the delivered checksum in the ack-frame is invalid.

See Also:

RawAckBase.getAckType(), Constant Field Values

Constructor Detail

PL132Ack

public PL132Ack(byte[] data,
                int offset)

Creates a new PL132 acknowledge frame out of a byte array.

The type of acknowledge returned for the created frame is always UNKNOWN_ACK, since no checksum of the associated frame request is supplied. Use getChecksum() to determine the type of acknowledge.

Parameters:

data - byte array containing the acknowledge frame

offset - start offset of frame structure in data, offset >= 0

PL132Ack

public PL132Ack(byte[] data,
                int offset,
                int requestChecksum)

Creates a new PL132 acknowledge frame out of a byte array.

Parameters:

data - byte array containing the acknowledge frame

offset - start offset of frame structure in data, offset >= 0

requestChecksum - checksum of the associated frame request

Method Detail

getChecksum

public final int getChecksum()

Returns the checksum contained in this acknowledge frame.

Returns:

checksum as unsigned short

toString

public java.lang.String toString()

Description copied from class: RawAckBase

Returns a textual representation of the acknowledge frame information.

Overrides:

toString in class RawAckBase

Returns:

string representation of the object