Package org.jgroups.protocols
Class SFC
- java.lang.Object
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- org.jgroups.stack.Protocol
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- org.jgroups.protocols.SFC
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public class SFC extends Protocol
Simple flow control protocol. After max_credits bytes sent to the group (or an individual member), the sender blocks until it receives an ack from all members that they indeed received max_credits bytes. Design in doc/design/SimpleFlowControl.txt
Note that SFC supports only flow control for multicast messages; unicast flow control is not supported ! Use FC if unicast flow control is required.- Version:
- $Id: SFC.java,v 1.19 2007/09/07 11:42:44 belaban Exp $
- Author:
- Bela Ban
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
SFC.Header
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Constructor Summary
Constructors Constructor Description SFC()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
down(Event evt)
An event is to be sent down the stack.java.util.Map<java.lang.String,java.lang.Object>
dumpStats()
double
getAverageBlockingTime()
long
getBlockings()
long
getBytesSent()
long
getCreditRequestsReceived()
long
getCreditRequestsSent()
long
getCredits()
long
getMaxCredits()
java.lang.String
getName()
long
getReplenishmentsReceived()
long
getReplenishmentsSent()
long
getTotalBlockingTime()
java.lang.String
printBlockingTimes()
java.lang.String
printPendingCreditors()
java.lang.String
printPendingRequesters()
java.lang.String
printReceived()
void
resetStats()
boolean
setProperties(java.util.Properties props)
Configures the protocol initially.void
start()
This method is called on aChannel.connect(String)
.void
stop()
This method is called on aChannel.disconnect()
.void
unblock()
java.lang.Object
up(Event evt)
An event was received from the layer below.-
Methods inherited from class org.jgroups.stack.Protocol
destroy, downThreadEnabled, enableStats, getDownProtocol, getProperties, getProtocolStack, getThreadFactory, getTransport, getUpProtocol, init, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, statsEnabled, upThreadEnabled
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Method Detail
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resetStats
public void resetStats()
- Overrides:
resetStats
in classProtocol
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getMaxCredits
public long getMaxCredits()
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getCredits
public long getCredits()
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getBytesSent
public long getBytesSent()
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getBlockings
public long getBlockings()
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getCreditRequestsSent
public long getCreditRequestsSent()
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getCreditRequestsReceived
public long getCreditRequestsReceived()
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getReplenishmentsReceived
public long getReplenishmentsReceived()
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getReplenishmentsSent
public long getReplenishmentsSent()
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getTotalBlockingTime
public long getTotalBlockingTime()
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getAverageBlockingTime
public double getAverageBlockingTime()
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dumpStats
public java.util.Map<java.lang.String,java.lang.Object> dumpStats()
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printBlockingTimes
public java.lang.String printBlockingTimes()
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printReceived
public java.lang.String printReceived()
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printPendingCreditors
public java.lang.String printPendingCreditors()
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printPendingRequesters
public java.lang.String printPendingRequesters()
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unblock
public void unblock()
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setProperties
public boolean setProperties(java.util.Properties props)
Description copied from class:Protocol
Configures the protocol initially. A configuration string consists of name=value items, separated by a ';' (semicolon), e.g.:"loopback=false;unicast_inport=4444"
- Overrides:
setProperties
in classProtocol
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down
public java.lang.Object down(Event evt)
Description copied from class:Protocol
An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack usingdown_prot.down()
. In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack usingup_prot.up()
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up
public java.lang.Object up(Event evt)
Description copied from class:Protocol
An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack usingdown_prot.down()
or c) the event (or another event) is sent up the stack usingup_prot.up()
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start
public void start() throws java.lang.Exception
Description copied from class:Protocol
This method is called on aChannel.connect(String)
. Starts work. Protocols are connected and queues are ready to receive events. Will be called from bottom to top. This call will replace the START and START_OK events.- Overrides:
start
in classProtocol
- Throws:
java.lang.Exception
- Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, soChannel.connect(String)
will throw an exception
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stop
public void stop()
Description copied from class:Protocol
This method is called on aChannel.disconnect()
. Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed
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