Package org.jgroups.protocols
Class FRAG
java.lang.Object
org.jgroups.stack.Protocol
org.jgroups.protocols.FRAG
Fragmentation layer. Fragments messages larger than FRAG_SIZE into smaller packets.
Reassembles fragmented packets into bigger ones. The fragmentation number is prepended
to the messages as a header (and removed at the receiving side).
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 FRAG 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.
- Version:
- $Id: FRAG.java,v 1.39.2.2 2008/07/22 14:08:59 belaban Exp $
- Author:
- Bela Ban, Filip Hanik
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Field Summary
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionFragment a packet if larger than frag_size (add a header).int
getName()
long
long
long
long
void
init()
Called after instance has been created (null constructor) and before protocol is started.void
void
setFragSize
(int s) boolean
setProperties
(Properties props) Setup the Protocol instance acording to the configuration stringIf event is a message, if it is fragmented, re-assemble fragments into big message and pass up the stack.Methods inherited from class org.jgroups.stack.Protocol
destroy, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getProperties, getProtocolStack, getThreadFactory, getTransport, getUpProtocol, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, start, statsEnabled, stop, upThreadEnabled
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Constructor Details
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FRAG
public FRAG()
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Method Details
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getName
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getFragSize
public int getFragSize() -
setFragSize
public void setFragSize(int s) -
getNumberOfSentMessages
public long getNumberOfSentMessages() -
getNumberOfSentFragments
public long getNumberOfSentFragments() -
getNumberOfReceivedMessages
public long getNumberOfReceivedMessages() -
getNumberOfReceivedFragments
public long getNumberOfReceivedFragments() -
setProperties
Setup the Protocol instance acording to the configuration string- Overrides:
setProperties
in classProtocol
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init
Description copied from class:Protocol
Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent. -
resetStats
public void resetStats()- Overrides:
resetStats
in classProtocol
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down
Fragment a packet if larger than frag_size (add a header). Otherwise just pass down. Only add a header if framentation is needed ! -
up
If event is a message, if it is fragmented, re-assemble fragments into big message and pass up the stack.
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