org.jgroups.protocols
Class SFC

java.lang.Object
  extended by org.jgroups.stack.Protocol
      extended by org.jgroups.protocols.SFC

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

Nested Class Summary
static class SFC.Header
           
 
Field Summary
 
Fields inherited from class org.jgroups.stack.Protocol
down_prot, log, props, stack, stats, up_prot
 
Constructor Summary
SFC()
           
 
Method Summary
 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 a Channel.connect(String).
 void stop()
          This method is called on a Channel.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
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SFC

public SFC()
Method Detail

resetStats

public void resetStats()
Overrides:
resetStats in class Protocol

getMaxCredits

public long getMaxCredits()

getCredits

public long getCredits()

getBytesSent

public long getBytesSent()

getBlockings

public long getBlockings()

getCreditRequestsSent

public long getCreditRequestsSent()

getCreditRequestsReceived

public long getCreditRequestsReceived()

getReplenishmentsReceived

public long getReplenishmentsReceived()

getReplenishmentsSent

public long getReplenishmentsSent()

getTotalBlockingTime

public long getTotalBlockingTime()

getAverageBlockingTime

public double getAverageBlockingTime()

dumpStats

public java.util.Map<java.lang.String,java.lang.Object> dumpStats()
Overrides:
dumpStats in class Protocol

printBlockingTimes

public java.lang.String printBlockingTimes()

printReceived

public java.lang.String printReceived()

printPendingCreditors

public java.lang.String printPendingCreditors()

printPendingRequesters

public java.lang.String printPendingRequesters()

unblock

public void unblock()

getName

public final java.lang.String getName()
Specified by:
getName in class Protocol

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 class Protocol

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 using down_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 using up_prot.up().

Overrides:
down in class Protocol

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 using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().

Overrides:
up in class Protocol

start

public void start()
           throws java.lang.Exception
Description copied from class: Protocol
This method is called on a Channel.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 class Protocol
Throws:
java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so Channel.connect(String) will throw an exception

stop

public void stop()
Description copied from class: Protocol
This method is called on a Channel.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

Overrides:
stop in class Protocol


Copyright © 1998-2008 Bela Ban. All Rights Reserved.