| java.lang.Object
 org.jgroups.stack.NakReceiverWindow
All known Subclasses: org.jgroups.protocols.pbcast.NAKACK,
| NakReceiverWindow | | public class NakReceiverWindow (Code) | | Keeps track of messages according to their sequence numbers. Allows
messages to be added out of order, and with gaps between sequence numbers.
Method remove() removes the first message with a sequence
number that is 1 higher than next_to_remove (this variable is
then incremented), or it returns null if no message is present, or if no
message's sequence number is 1 higher.
When there is a gap upon adding a message, its seqno will be added to the
Retransmitter, which (using a timer) requests retransmissions of missing
messages and keeps on trying until the message has been received, or the
member who sent the message is suspected.
Started out as a copy of SlidingWindow. Main diff: RetransmitCommand is
different, and retransmission thread is only created upon detection of a
gap.
Change Nov 24 2000 (bela): for PBCAST, which has its own retransmission
(via gossip), the retransmitter thread can be turned off
Change April 25 2001 (igeorg):
i. Restructuring: placed all nested class definitions at the top, then
class static/non-static variables, then class private/public methods.
ii. Class and all nested classes are thread safe. Readers/writer lock
added on NakReceiverWindow for finer grained locking.
iii. Internal or externally provided retransmission scheduler thread.
iv. Exponential backoff in time for retransmissions.
author:
Bela Ban May 27 1999, May 2004
author:
John Georgiadis May 8 2001 |
| Inner Class :public interface Listener | |
| Field Summary | |
| final protected static Log | log
|
| Method Summary | |
| public void | add(long seqno, Message msg)
Adds a message according to its sequence number (ordered).
Variables head and tail mark the start and
end of the messages received, but not delivered yet. | | public void | destroy()
| | public Message | get(long sequence_num)
Returns the message from received_msgs or delivered_msgs. | | public long | getHighestDelivered()
| | public long | getHighestReceived()
Returns the highest sequence number received so far (which may be
higher than the highest seqno delivered so far; e.g., for
1,2,3,5,6 it would be 6. | | public long | getHighestSeen()
Returns the highest deliverable seqno; e.g., for 1,2,3,5,6 it would
be 3. | | public long | getLowestSeen()
| | public int | getMaxXmitBufSize()
| | public List | getMessagesHigherThan(long seqno)
Return messages that are higher than seqno (excluding
seqno). | | public List | getMessagesInList(List missing_msgs)
Return a list of all messages for which there is a seqno in
missing_msgs. | | public List | getMessagesInRange(long lower, long upper)
Return all messages m for which the following holds:
m > lower && m <= upper (excluding lower, including upper). | | public List | getMissingMessages(long low, long high)
Find all messages between 'low' and 'high' (including 'low' and
'high') that have a null msg.
Return them as a list of longs
List. | | String | printDeliveredMessages()
Prints delivered_msgs. | | String | printReceivedMessages()
Prints received_msgs. | | public Message | remove()
| | public void | reset()
| | public void | setDiscardDeliveredMessages(boolean flag)
| | public void | setListener(Listener l)
| | public void | setMaxXmitBufSize(int max_xmit_buf_size)
| | public void | setRetransmitTimeouts(long[] timeouts)
| | public int | size()
| | public void | stable(long seqno)
Delete all messages <= seqno (they are stable, that is, have been
received at all members). | | public String | toString()
| | void | updateHighestSeen()
|
| log | | final protected static Log log(Code) | | |
| NakReceiverWindow | | public NakReceiverWindow(Address sender, Retransmitter.RetransmitCommand cmd, long start_seqno, TimeScheduler sched)(Code) | | Creates a new instance with the given retransmit command
Parameters:
sender - The sender associated with this instance
Parameters:
cmd - The command used to retransmit a missing message, willbe invoked by the table. If null, the retransmit thread will not bestarted
Parameters:
start_seqno - The first sequence number to be received
Parameters:
sched - the external scheduler to use for retransmissionrequests of missing msgs. If it's not provided or is null, an internalone is created |
| NakReceiverWindow | | public NakReceiverWindow(Address sender, Retransmitter.RetransmitCommand cmd, long start_seqno)(Code) | | Creates a new instance with the given retransmit command
Parameters:
sender - The sender associated with this instance
Parameters:
cmd - The command used to retransmit a missing message, willbe invoked by the table. If null, the retransmit thread will not bestarted
Parameters:
start_seqno - The first sequence number to be received |
| NakReceiverWindow | | public NakReceiverWindow(Address sender, long start_seqno)(Code) | | Creates a new instance without a retransmission thread
Parameters:
sender - The sender associated with this instance
Parameters:
start_seqno - The first sequence number to be received |
| add | | public void add(long seqno, Message msg)(Code) | | Adds a message according to its sequence number (ordered).
Variables head and tail mark the start and
end of the messages received, but not delivered yet. When a message is
received, if its seqno is smaller than head, it is
discarded (already received). If it is bigger than tail,
we advance tail and add empty elements. If it is between
head and tail, we set the corresponding
missing (or already present) element. If it is equal to
tail, we advance the latter by 1 and add the message
(default case).
|
| destroy | | public void destroy()(Code) | | Stop the retransmitter and reset the nak window
|
| get | | public Message get(long sequence_num)(Code) | | Returns the message from received_msgs or delivered_msgs.
Parameters:
sequence_num - Message from received_msgs or delivered_msgs. |
| getHighestDelivered | | public long getHighestDelivered()(Code) | | the highest sequence number of a message consumed by theapplication (by remove()) |
| getHighestReceived | | public long getHighestReceived()(Code) | | Returns the highest sequence number received so far (which may be
higher than the highest seqno delivered so far; e.g., for
1,2,3,5,6 it would be 6.
See Also: NakReceiverWindow.getHighestSeen |
| getLowestSeen | | public long getLowestSeen()(Code) | | the lowest sequence number of a message that has beendelivered or is a candidate for delivery (by the next call toremove()) |
| getMaxXmitBufSize | | public int getMaxXmitBufSize()(Code) | | |
| getMessagesHigherThan | | public List getMessagesHigherThan(long seqno)(Code) | | Return messages that are higher than seqno (excluding
seqno). Check both received and delivered
messages.
List. All messages that have a seqno greater than seqno |
| getMessagesInList | | public List getMessagesInList(List missing_msgs)(Code) | | Return a list of all messages for which there is a seqno in
missing_msgs. The seqnos of the argument list are
supposed to be in ascending order
Parameters:
missing_msgs - A List of seqnos List |
| getMessagesInRange | | public List getMessagesInRange(long lower, long upper)(Code) | | Return all messages m for which the following holds:
m > lower && m <= upper (excluding lower, including upper). Check both
received_msgs and delivered_msgs.
|
| getMissingMessages | | public List getMissingMessages(long low, long high)(Code) | | Find all messages between 'low' and 'high' (including 'low' and
'high') that have a null msg.
Return them as a list of longs
List. A list of seqnos, sorted in ascending order.E.g. [1, 4, 7, 8] |
| printDeliveredMessages | | String printDeliveredMessages()(Code) | | Prints delivered_msgs. Requires read lock present.
String |
| printReceivedMessages | | String printReceivedMessages()(Code) | | Prints received_msgs. Requires read lock to be present
String |
| reset | | public void reset()(Code) | | Reset the retransmitter and the nak window
|
| setDiscardDeliveredMessages | | public void setDiscardDeliveredMessages(boolean flag)(Code) | | |
| setListener | | public void setListener(Listener l)(Code) | | |
| setMaxXmitBufSize | | public void setMaxXmitBufSize(int max_xmit_buf_size)(Code) | | |
| setRetransmitTimeouts | | public void setRetransmitTimeouts(long[] timeouts)(Code) | | |
| stable | | public void stable(long seqno)(Code) | | Delete all messages <= seqno (they are stable, that is, have been
received at all members). Stop when a number > seqno is encountered
(all messages are ordered on seqnos).
|
| updateHighestSeen | | void updateHighestSeen()(Code) | | Start from the current sequence number and set highest_seen until we find a gap (null value in the entry)
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