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java.lang.Objectorg.jgroups.stack.Protocol
org.jgroups.protocols.FD_PROB
Probabilistic failure detection protocol based on "A Gossip-Style Failure Detection Service" by Renesse, Minsky and Hayden.
Each member maintains a list of all other members: for each member P, 2 data are maintained, a heartbeat counter and the time of the last increment of the counter. Each member periodically sends its own heartbeat counter list to a randomly chosen member Q. Q updates its own heartbeat counter list and the associated time (if counter was incremented). Each member periodically increments its own counter. If, when sending its heartbeat counter list, a member P detects that another member Q's heartbeat counter was not incremented for timeout seconds, Q will be suspected.
This protocol can be used both with a PBCAST *and* regular stacks.
Nested Class Summary | |
static class |
FD_PROB.FdHeader
|
Field Summary |
Fields inherited from class org.jgroups.stack.Protocol |
down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, up_handler, up_prot, up_queue, up_thread, up_thread_prio |
Constructor Summary | |
FD_PROB()
|
Method Summary | |
void |
down(Event evt)
An event is to be sent down the stack. |
java.lang.String |
getName()
|
void |
run()
Loop while more than 1 member available. |
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 |
up(Event evt)
An event was received from the layer below. |
Methods inherited from class org.jgroups.stack.Protocol |
destroy, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, passDown, passUp, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setUpProtocol, startDownHandler, startUpHandler, stopInternal |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public FD_PROB()
Method Detail |
public java.lang.String getName()
getName
in class Protocol
public boolean setProperties(java.util.Properties props)
Protocol
"loopback=false;unicast_inport=4444"
setProperties
in class Protocol
public void start() throws java.lang.Exception
Protocol
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.
start
in class Protocol
java.lang.Exception
- Thrown if protocol cannot be started successfully. This will cause the ProtocolStack
to fail, so Channel.connect(String)
will throw an exceptionpublic void stop()
Protocol
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
stop
in class Protocol
public void up(Event evt)
Protocol
passDown()
or c) the event (or another event) is sent up
the stack using passUp()
.
up
in class Protocol
public void down(Event evt)
Protocol
passDown()
. 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 passUp()
.
down
in class Protocol
public void run()
run
in interface java.lang.Runnable
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