Package org.jgroups.protocols
Class FRAG3
- java.lang.Object
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- org.jgroups.stack.Protocol
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- org.jgroups.protocols.Fragmentation
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- org.jgroups.protocols.FRAG3
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- All Implemented Interfaces:
Lifecycle
public class FRAG3 extends Fragmentation
Fragmentation protocol which uses less memory to store fragments thanFRAG2
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When a message is fragmented, all fragments carry the size of the original message, their offset and length with respect to the original message and a fragment ID (to identify the fragment).
When the first fragment is received, the full message is created and each fragment copies its data into the full message at its offset and length. When all fragments have been received, the full message is passed up.
Only the first fragment carries the headers and dest and src addresses. When received, its src/dest addresses and the headers will be set in the full message.
For details see https://issues.redhat.com/browse/JGRP-2154
Requirement: lossless delivery (e.g. NAKACK2 or UNICAST3). No requirement on ordering. Works for both unicast and multicast messages.- Since:
- 4.0
- Author:
- Bela Ban
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected class
FRAG3.FragEntry
Entry for a full message, received fragments are copied into buffer and set in the bitset of expected frags.
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Field Summary
Fields Modifier and Type Field Description protected AverageMinMax
avg_size_down
protected AverageMinMax
avg_size_up
protected java.util.concurrent.atomic.AtomicInteger
curr_id
protected java.util.concurrent.ConcurrentMap<Address,java.util.concurrent.ConcurrentMap<java.lang.Integer,FRAG3.FragEntry>>
fragment_list
protected java.util.function.Predicate<Message>
HAS_FRAG_HEADER
protected java.util.List<Address>
members
protected MessageFactory
msg_factory
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Fields inherited from class org.jgroups.protocols.Fragmentation
frag_size, num_frags_received, num_frags_sent
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Fields inherited from class org.jgroups.stack.Protocol
after_creation_hook, down_prot, ergonomics, id, local_addr, log, policies, stack, stats, up_prot
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Constructor Summary
Constructors Constructor Description FRAG3()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clearAllFragments()
void
clearFragmentsFor(Address mbr)
java.lang.Object
down(Event evt)
Fragment a packet if larger than frag_size (add a header).java.lang.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 !).java.lang.String
getAvgSizeDown()
java.lang.String
getAvgSizeUp()
protected int
getNextId()
protected void
handleViewChange(View view)
void
init()
Called after a protocol has been created and before the protocol is started.void
resetStats()
protected Message
unfragment(Message msg, Frag3Header hdr)
1.java.lang.Object
up(Event evt)
If event is a message, if it is fragmented, re-assemble fragments into big message and pass up the stack.java.lang.Object
up(Message msg)
A single message was received.void
up(MessageBatch batch)
Sends up a multiple messages in aMessageBatch
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Methods inherited from class org.jgroups.protocols.Fragmentation
getFragSize, getNumberOfReceivedFragments, getNumberOfSentFragments, setFragSize
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Methods inherited from class org.jgroups.stack.Protocol
accept, addPolicy, addr, addr, afterCreationHook, destroy, down, enableStats, getAddress, getComponents, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getPolicies, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, policies, providedDownServices, providedUpServices, removePolicy, requiredDownServices, requiredUpServices, resetStatistics, setAddress, setDownProtocol, setErgonomics, setId, setLevel, setPolicies, setProtocolStack, setSocketFactory, setUpProtocol, setValue, start, statsEnabled, stop, toString
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Field Detail
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fragment_list
protected final java.util.concurrent.ConcurrentMap<Address,java.util.concurrent.ConcurrentMap<java.lang.Integer,FRAG3.FragEntry>> fragment_list
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HAS_FRAG_HEADER
protected final java.util.function.Predicate<Message> HAS_FRAG_HEADER
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curr_id
protected final java.util.concurrent.atomic.AtomicInteger curr_id
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members
protected final java.util.List<Address> members
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msg_factory
protected MessageFactory msg_factory
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avg_size_down
protected final AverageMinMax avg_size_down
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avg_size_up
protected final AverageMinMax avg_size_up
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Method Detail
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getAvgSizeDown
public java.lang.String getAvgSizeDown()
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getAvgSizeUp
public java.lang.String getAvgSizeUp()
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getNextId
protected int getNextId()
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init
public void init() throws java.lang.Exception
Description copied from class:Protocol
Called after a protocol has been created and before the protocol is started. Attributes are already set. Other protocols are not yet connected and events cannot yet be sent.
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resetStats
public void resetStats()
- Overrides:
resetStats
in classFragmentation
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down
public java.lang.Object down(Event evt)
Fragment a packet if larger than frag_size (add a header). Otherwise just pass down. Only add a header if fragmentation is needed !
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down
public java.lang.Object down(Message msg)
Description copied from class:Protocol
A message is sent down the stack. Protocols may examine the message and do something (e.g. add a header) with it, before passing it down.
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up
public java.lang.Object up(Event evt)
If event is a message, if it is fragmented, re-assemble fragments into big message and pass up the stack.
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up
public java.lang.Object up(Message msg)
Description copied from class:Protocol
A single message was received. Protocols may examine the message and do something (e.g. add a header) with it before passing it up.
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up
public void up(MessageBatch batch)
Description copied from class:Protocol
Sends up a multiple messages in aMessageBatch
. 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 (callingProtocol.accept(Message)
), and - if true - callsProtocol.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. usingMessageBatch.iterator(Predicate)
), 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.
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handleViewChange
protected void handleViewChange(View view)
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clearFragmentsFor
public void clearFragmentsFor(Address mbr)
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clearAllFragments
public void clearAllFragments()
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fragment
protected void fragment(Message msg)
Send all fragments as separate messages (with same ID !). Example: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}
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unfragment
protected Message unfragment(Message msg, Frag3Header hdr)
1. Get all the fragment buffers 2. When all are received -> Assemble them into one big buffer 3. Read headers and byte buffer from big buffer 4. Set headers and buffer in msg 5. Return the message
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