com.fr.third.jgroups.protocols

类 MFC

java.lang.Object

com.fr.third.jgroups.stack.Protocol

com.fr.third.jgroups.protocols.FlowControl

com.fr.third.jgroups.protocols.MFC

public class MFC
extends FlowControl

Simple flow control protocol based on a credit system. Each sender has a number of credits (bytes to send). When the credits have been exhausted, the sender blocks. Each receiver also keeps track of how many credits it has received from a sender. When credits for a sender fall below a threshold, the receiver sends more credits to the sender. Works for both unicast and multicast messages.

Note that this protocol must be located towards the top of the stack, or all down_threads from JChannel to this protocol must be set to false ! This is in order to block JChannel.send()/JChannel.down().
This is the second simplified implementation of the same model. The algorithm is sketched out in doc/FlowControl.txt
Changes (Brian) April 2006:

1. Receivers now send credits to a sender when more than min_credits have been received (rather than when min_credits are left)
2. Receivers don't send the full credits (max_credits), but rather the actual number of bytes received

作者:

Bela Ban

嵌套类概要

从类继承的嵌套类/接口 com.fr.third.jgroups.protocols.FlowControl

FlowControl.Credit

字段概要

字段

限定符和类型	字段和说明
protected CreditMap	credits Maintains credits per member
protected long	last_credit_request Last time a credit request was sent.

从类继承的字段 com.fr.third.jgroups.protocols.FlowControl

CREDIT_REQUEST_HDR, frag_size, ignore_synchronous_response, local_addr, max_block_time, max_block_times, max_credits, min_credits, min_threshold, num_credit_requests_received, num_credit_requests_sent, num_credit_responses_received, num_credit_responses_sent, received, REPLENISH_HDR, running

从类继承的字段 com.fr.third.jgroups.stack.Protocol

down_prot, ergonomics, id, log, name, stack, stats, up_prot

构造器概要

构造器

构造器和说明
MFC()

方法概要

方法

限定符和类型	方法和说明
double	getAverageTimeBlocked()
int	getNumberOfBlockings()
protected void	handleCredit(Address sender, long increase)
protected java.lang.Object	handleDownMessage(Event evt, Message msg, Address dest, int length)
protected boolean	handleMulticastMessage() Whether the protocol handles message with dest == null || dest.isMulticastAddress()
protected void	handleViewChange(java.util.List<Address> mbrs)
void	init() Called after instance has been created (null constructor) and before protocol is started.
protected boolean	needToSendCreditRequest()
java.lang.String	printCredits()
java.lang.String	printSenderCredits()
void	resetStats()
void	stop() This method is called on a Channel.disconnect().
void	unblock() Allows to unblock a blocked sender from an external program, e.g.

从类继承的方法 com.fr.third.jgroups.protocols.FlowControl

adjustCredit, down, dumpStats, getMaxBlockTime, getMaxBlockTime, getMaxBlockTimes, getMaxCredits, getMinCredits, getMinThreshold, getNumberOfCreditRequestsReceived, getNumberOfCreditRequestsSent, getNumberOfCreditResponsesReceived, getNumberOfCreditResponsesSent, handleConfigEvent, handleCreditRequest, handleUpEvent, printMap, printReceiverCredits, sendCredit, sendCreditRequest, setMaxBlockTime, setMaxBlockTimes, setMaxCredits, setMinCredits, setMinThreshold, start, up, up

从类继承的方法 com.fr.third.jgroups.stack.Protocol

accept, destroy, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料

credits

protected CreditMap credits

Maintains credits per member

last_credit_request

protected long last_credit_request

Last time a credit request was sent. Used to prevent credit request storms

构造器详细资料

MFC

public MFC()

方法详细资料

unblock

public void unblock()

Allows to unblock a blocked sender from an external program, e.g. JMX

覆盖:

unblock 在类中 FlowControl

printCredits

public java.lang.String printCredits()

覆盖:

printCredits 在类中 FlowControl

printSenderCredits

public java.lang.String printSenderCredits()

指定者:

printSenderCredits 在类中 FlowControl

getNumberOfBlockings

public int getNumberOfBlockings()

指定者:

getNumberOfBlockings 在类中 FlowControl

getAverageTimeBlocked

public double getAverageTimeBlocked()

指定者:

getAverageTimeBlocked 在类中 FlowControl

handleMulticastMessage

protected boolean handleMulticastMessage()

从类复制的说明: FlowControl

Whether the protocol handles message with dest == null || dest.isMulticastAddress()

指定者:

handleMulticastMessage 在类中 FlowControl

返回:

init

public void init()
          throws java.lang.Exception

从类复制的说明: 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.

覆盖:

init 在类中 FlowControl

抛出:

java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception

stop

public void stop()

从类复制的说明: 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

覆盖:

stop 在类中 FlowControl

resetStats

public void resetStats()

覆盖:

resetStats 在类中 FlowControl

handleDownMessage

protected java.lang.Object handleDownMessage(Event evt,
                                 Message msg,
                                 Address dest,
                                 int length)

指定者:

handleDownMessage 在类中 FlowControl

needToSendCreditRequest

protected boolean needToSendCreditRequest()

handleCredit

protected void handleCredit(Address sender,
                long increase)

指定者:

handleCredit 在类中 FlowControl

handleViewChange

protected void handleViewChange(java.util.List<Address> mbrs)

覆盖:

handleViewChange 在类中 FlowControl