net.sf.jrtps.message

Class AckNack

java.lang.Object

net.sf.jrtps.message.SubMessage

net.sf.jrtps.message.AckNack

public class AckNack
extends SubMessage

This Submessage is used to communicate the state of a Reader to a Writer. The Submessage allows the Reader to inform the Writer about the sequence numbers it has received and which ones it is still missing. This Submessage can be used to do both positive and negative acknowledgments.

see 8.3.7.1 AckNack

Author:

mcr70

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.jrtps.message.SubMessage

SubMessage.Kind

Field Summary

Fields

Modifier and Type	Field and Description
static int	KIND

Fields inherited from class net.sf.jrtps.message.SubMessage

header

Constructor Summary

Constructors

Constructor and Description
AckNack(EntityId readerId, EntityId writerId, SequenceNumberSet readerSnSet, int count)

Method Summary

Modifier and Type	Method and Description
boolean	finalFlag() Final flag indicates to the Writer whether a response is mandatory.
void	finalFlag(boolean value) Sets the finalFlag.
int	getCount() A counter that is incremented each time a new AckNack message is sent.
EntityId	getReaderId() Identifies the Reader entity that acknowledges receipt of certain sequence numbers and/or requests to receive certain sequence numbers.
SequenceNumberSet	getReaderSNState() Communicates the state of the reader to the writer.
EntityId	getWriterId() Identifies the Writer entity that is the target of the AckNack message.
String	toString()
void	writeTo(RTPSByteBuffer bb) Writes this SubMessage into given RTPSByteBuffer.

Methods inherited from class net.sf.jrtps.message.SubMessage

getHeader, getKind

Methods inherited from class java.lang.Object

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

Field Detail

KIND

public static final int KIND

See Also:

Constant Field Values

Constructor Detail

AckNack

public AckNack(EntityId readerId,
               EntityId writerId,
               SequenceNumberSet readerSnSet,
               int count)

Method Detail

finalFlag

public boolean finalFlag()

Final flag indicates to the Writer whether a response is mandatory.

Returns:

true, if response is NOT mandatory

finalFlag

public void finalFlag(boolean value)

Sets the finalFlag.

Parameters:

value - Final flag

getReaderId

public EntityId getReaderId()

Identifies the Reader entity that acknowledges receipt of certain sequence numbers and/or requests to receive certain sequence numbers.

Returns:

reader id

getWriterId

public EntityId getWriterId()

Identifies the Writer entity that is the target of the AckNack message. This is the Writer Entity that is being asked to re-send some sequence numbers or is being informed of the reception of certain sequence numbers.

Returns:

writer id

getReaderSNState

public SequenceNumberSet getReaderSNState()

Communicates the state of the reader to the writer. All sequence numbers up to the one prior to readerSNState.base are confirmed as received by the reader. The sequence numbers that appear in the set indicate missing sequence numbers on the reader side. The ones that do not appear in the set are undetermined (could be received or not).

Returns:

readerSNState

getCount

public int getCount()

A counter that is incremented each time a new AckNack message is sent. Provides the means for a Writer to detect duplicate AckNack messages that can result from the presence of redundant communication paths.

Returns:

count

writeTo

public void writeTo(RTPSByteBuffer bb)

Description copied from class: SubMessage

Writes this SubMessage into given RTPSByteBuffer.

Specified by:

writeTo in class SubMessage

Parameters:

bb - RTPSByteBuffer

toString

public String toString()

Overrides:

toString in class SubMessage