JavaGroups.JavaStack.Protocols
Class MERGE

java.lang.Object
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  +--JavaGroups.JavaStack.Protocol
        |
        +--JavaGroups.JavaStack.Protocols.MERGE

public class MERGE

extends Protocol

implements java.lang.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 BECOME_SERVER event.

Constructor Summary

MERGE()

Method Summary

void	Down(Event evt) An event is to be sent down the stack.
java.lang.String	GetName()
void	run() If IP multicast: periodically mcast a HELLO message If gossiping: periodically retrieve the membership.
boolean	SetProperties(java.util.Properties props) Configures the protocol initially.
void	Up(Event evt) An event was received from the layer below.

Methods inherited from class JavaGroups.JavaStack.Protocol

GetDownProtocol, GetProperties, GetUpProtocol, PassDown, PassUp, ProvidedDownServices, ProvidedUpServices, RequiredDownServices, RequiredUpServices, Reset, SetDownProtocol, SetProtocolStack, SetUpProtocol, StartDownHandler, StartUpHandler, StopInternal

Methods inherited from class java.lang.Object

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

Constructor Detail

MERGE

public MERGE()

Method Detail

GetName

public java.lang.String GetName()

Overrides:

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

Up

public void 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 PassDown or c) the event (or another event) is sent up the stack using PassUp.

Overrides:

Up in class Protocol

Down

public void 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 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.

Overrides:

Down in class 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).

Specified by:

run in interface java.lang.Runnable