org.jgroups.protocols
Class MERGE
- Runnable
public class MERGE
implements Runnable
Simple and stupid MERGE protocol (does not take into account state transfer).
Periodically mcasts a HELLO message with its own address. When a HELLO message is
received from a member that has the same group (UDP discards all messages with a group
name different that our own), but is not currently in the group, a MERGE event is sent
up the stack. The protocol starts working upon receiving a View in which it is the coordinator.
- Gianluca Collot, Jan 2001
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 |
destroy , down , getDownProtocol , getDownQueue , getName , getProperties , getUpProtocol , getUpQueue , handleSpecialDownEvent , init , passDown , passUp , providedDownServices , providedUpServices , receiveDownEvent , receiveUpEvent , requiredDownServices , requiredUpServices , setDownProtocol , setObserver , setProperties , setPropertiesInternal , setProtocolStack , setUpProtocol , start , startDownHandler , startUpHandler , stop , stopInternal , up |
down
public void down(Event evt)
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 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 interface Protocol
getName
public String getName()
- getName in interface Protocol
run
public void run()
If IP multicast: periodically mcast a HELLO message
If gossiping: periodically retrieve the membership. Any members not part of our
own membership are merged (passing MERGE event up).
setProperties
public boolean setProperties(Properties props)
Configures the protocol initially. A configuration string consists of name=value
items, separated by a ';' (semicolon), e.g.:
"loopback=false;unicast_inport=4444"
- setProperties in interface Protocol
start
public void start()
throws Exception
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.
- start in interface Protocol
stop
public void stop()
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
- stop in interface Protocol
up
public void up(Event evt)
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 passDown()
or c) the event (or another event) is sent up
the stack using passUp()
.
- up in interface Protocol
Copyright B) 2001,2002 www.jgroups.com . All Rights Reserved.