org.jgroups.stack

Class AckReceiverWindow

java.lang.Object

org.jgroups.stack.AckReceiverWindow

public class AckReceiverWindow
extends Object

Counterpart of AckSenderWindow. Simple FIFO buffer. Every message received is ACK'ed (even duplicates) and added to a hashmap keyed by seqno. The next seqno to be received is stored in next_to_remove. When a message with a seqno less than next_to_remove is received, it will be discarded. The remove() method removes and returns a message whose seqno is equal to next_to_remove, or null if not found.
Change May 28 2002 (bela): replaced TreeSet with HashMap. Keys do not need to be sorted, and adding a key to a sorted set incurs overhead.

Author:

Bela Ban

Field Summary

Fields

Modifier and Type	Field and Description
static Message	TOMBSTONE

Constructor Summary

Constructors

Constructor and Description
AckReceiverWindow(long initial_seqno)
AckReceiverWindow(long initial_seqno, int segment_capacity)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(long seqno, Message msg) Adds a new message.
byte	add2(long seqno, Message msg) Adds a message if not yet received
AtomicBoolean	getProcessing()
String	printMessages()
Message	remove() Removes a message whose seqno is equal to next_to_remove, increments the latter.
Tuple<List<Message>,Long>	removeMany(int max) Removes as many messages as possible (in sequence, without gaps)
List<Message>	removeManyAsList(int max)
void	reset()
int	size()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

TOMBSTONE

public static final Message TOMBSTONE

Constructor Detail

AckReceiverWindow

public AckReceiverWindow(long initial_seqno)

AckReceiverWindow

public AckReceiverWindow(long initial_seqno,
                 int segment_capacity)

Method Detail

getProcessing

public AtomicBoolean getProcessing()

add

public boolean add(long seqno,
          Message msg)

Adds a new message. Message cannot be null

Returns:

True if the message was added, false if not (e.g. duplicate, message was already present)

add2

public byte add2(long seqno,
        Message msg)

Adds a message if not yet received

Parameters:

seqno -

msg -

Returns:

-1 if not added because seqno < next_to_remove, 0 if not added because already present, 1 if added successfully

remove

public Message remove()

Removes a message whose seqno is equal to next_to_remove, increments the latter. Returns message that was removed, or null, if no message can be removed. Messages are thus removed in order.

removeMany

public Tuple<List<Message>,Long> removeMany(int max)

Removes as many messages as possible (in sequence, without gaps)

Parameters:

max - Max number of messages to be removed

Returns:

Tuple,Long>: a tuple of the message list and the highest seqno removed

removeManyAsList

public List<Message> removeManyAsList(int max)

reset

public void reset()

size

public int size()

toString

public String toString()

Overrides:

toString in class Object

printMessages

public String printMessages()