public class FRAG2 extends Protocol
Each fragment is identified by (a) the sender (part of the message to which the header is appended), (b) the fragmentation ID (which is unique per FRAG2 layer (monotonically increasing) and (c) the fragement ID which ranges from 0 to number_of_fragments-1.
Requirement: lossless delivery (e.g. NAK, ACK). No requirement on ordering.
Works for both unicast and multicast messages.
Compared to FRAG, this
protocol does not need to serialize the message in order to break
it into smaller fragments: it looks only at the message's buffer, which is a
byte[] array anyway. We assume that the size addition for headers and src and
dest address is minimal when the transport finally has to serialize the
message, so we add a constant (200 bytes).
Modifier and Type | Class and Description |
---|---|
protected static class |
FRAG2.FragEntry
Class represents an entry for a message.
|
Modifier and Type | Field and Description |
---|---|
protected AverageMinMax |
avg_size_down |
protected AverageMinMax |
avg_size_up |
protected int |
curr_id
Used to assign fragmentation-specific sequence IDs (monotonically increasing)
|
protected int |
frag_size |
protected ConcurrentMap<Address,ConcurrentMap<Long,FRAG2.FragEntry>> |
fragment_list |
protected Address |
local_addr |
protected List<Address> |
members |
protected LongAdder |
num_frags_received |
protected LongAdder |
num_frags_sent |
after_creation_hook, down_prot, ergonomics, id, log, stack, stats, up_prot
Constructor and Description |
---|
FRAG2() |
Modifier and Type | Method and Description |
---|---|
void |
clearAllFragments() |
void |
clearFragmentsFor(Address mbr) |
Object |
down(Event evt)
Fragment a packet if larger than frag_size (add a header).
|
Object |
down(Message msg)
A message is sent down the stack.
|
protected void |
fragment(Message msg)
Send all fragments as separate messages (with same ID !).
|
int |
fragSize() |
FRAG2 |
fragSize(int size) |
String |
getAvgSizeDown() |
String |
getAvgSizeUp() |
int |
getFragSize() |
long |
getNumberOfReceivedFragments() |
long |
getNumberOfSentFragments() |
protected void |
handleViewChange(View view) |
void |
init()
Called after instance has been created (null constructor) and before protocol is started.
|
void |
resetStats() |
void |
setFragSize(int s) |
protected Message |
unfragment(Message msg,
FragHeader hdr)
1.
|
Object |
up(Event evt)
If event is a message, if it is fragmented, re-assemble fragments into big message and pass up the stack.
|
Object |
up(Message msg)
A single message was received.
|
void |
up(MessageBatch batch)
Sends up a multiple messages in a
MessageBatch . |
accept, afterCreationHook, destroy, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, setDownProtocol, setErgonomics, setId, setLevel, setProperties, setProtocolStack, setSocketFactory, setUpProtocol, setValue, start, statsEnabled, stop
protected int frag_size
protected final ConcurrentMap<Address,ConcurrentMap<Long,FRAG2.FragEntry>> fragment_list
protected int curr_id
protected Address local_addr
protected LongAdder num_frags_sent
protected LongAdder num_frags_received
protected final AverageMinMax avg_size_down
protected final AverageMinMax avg_size_up
public int getFragSize()
public void setFragSize(int s)
public long getNumberOfSentFragments()
public long getNumberOfReceivedFragments()
public int fragSize()
public FRAG2 fragSize(int size)
public String getAvgSizeDown()
public String getAvgSizeUp()
public void init() throws Exception
Protocol
public void resetStats()
resetStats
in class Protocol
public Object down(Event evt)
public Object down(Message msg)
Protocol
public Object up(Event evt)
public Object up(Message msg)
Protocol
public void up(MessageBatch batch)
Protocol
MessageBatch
. The sender of the batch is always the same, and so is the
destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed
messages, although the transport itself will create initial MessageBatches that contain only either OOB or
regular messages.
The default processing below sends messages up the stack individually, based on a matching criteria
(calling Protocol.accept(org.jgroups.Message)
), and - if true - calls Protocol.up(org.jgroups.Event)
for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.
Subclasses should check if there are any messages destined for them (e.g. using
MessageBatch.getMatchingMessages(short,boolean)
), then possibly remove and process them and finally pass
the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all
encrypted messages in the batch, not remove them, and pass the batch up when done.protected void handleViewChange(View view)
public void clearFragmentsFor(Address mbr)
public void clearAllFragments()
protected void fragment(Message msg)
Given the generated ID is 2344, number of fragments=3, message {dst,src,buf} would be fragmented into: [2344,3,0]{dst,src,buf1}, [2344,3,1]{dst,src,buf2} and [2344,3,2]{dst,src,buf3}
protected Message unfragment(Message msg, FragHeader hdr)
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