Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> jgroups >> [ protocols overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---

org.jgroups.protocols
Class Discovery  

java.lang.Object
  org.jgroups.stack.Protocol
      org.jgroups.protocols.Discovery

Direct Known Subclasses:

PING, TCPGOSSIP, TCPPING, WANPING

---

public abstract class Discovery

extends org.jgroups.stack.Protocol

The Discovery protocol layer retrieves the initial membership (used by the GMS when started by sending event FIND_INITIAL_MBRS down the stack). We do this by specific subclasses, e.g. by mcasting PING requests to an IP MCAST address or, if gossiping is enabled, by contacting the GossipServer. The responses should allow us to determine the coordinator whom we have to contact, e.g. in case we want to join the group. When we are a server (after having received the BECOME_SERVER event), we'll respond to PING requests with a PING response.

The FIND_INITIAL_MBRS event will eventually be answered with a FIND_INITIAL_MBRS_OK event up the stack. The following properties are available

• timeout - the timeout (ms) to wait for the initial members, default is 3000=3 secs
• num_initial_members - the minimum number of initial members for a FIND_INITAL_MBRS, default is 2
• num_ping_requests - the number of GET_MBRS_REQ messages to be sent (min=1), distributed over timeout ms

Version:

$Id: Discovery.java,v 1.13 2005/08/11 12:43:47 belaban Exp $

---

Field Summary
(package private)  java.lang.String	group_addr
(package private)  boolean	is_server
(package private)  org.jgroups.Address	local_addr
(package private)  java.util.Vector	members
(package private)  java.util.Set	members_set
(package private)  int	num_discovery_requests
(package private)  int	num_initial_members
(package private)  int	num_ping_requests           Number of GET_MBRS_REQ messages to be sent (min=1), distributed over timeout ms
(package private)  PingWaiter	ping_waiter
(package private)  long	timeout

 

Fields inherited from class org.jgroups.stack.Protocol

down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, stats, trace, up_handler, up_prot, up_queue, up_thread, up_thread_prio, warn

 

Constructor Summary

Discovery()

 

Method Summary
void	down(org.jgroups.Event evt)           An event is to be sent down the stack.
java.util.Vector	findInitialMembers()           Finds the initial membership
java.lang.String	findInitialMembersAsString()
int	getNumberOfDiscoveryRequestsSent()
int	getNumInitialMembers()
int	getNumPingRequests()
long	getTimeout()
void	handleConnect()
void	handleConnectOK()           Called when CONNECT_OK has been received
void	handleDisconnect()
void	localAddressSet(org.jgroups.Address addr)           Called after local_addr was set
protected  org.jgroups.View	makeView(java.util.Vector mbrs)
java.util.Vector	providedUpServices()           List of events that are provided to layers above (they will be handled when sent down from above).
void	resetStats()
abstract  void	sendGetMembersRequest()
void	setNumInitialMembers(int num_initial_members)
void	setNumPingRequests(int num_ping_requests)
boolean	setProperties(java.util.Properties props)           sets the properties of the PING protocol.
void	setTimeout(long timeout)
void	start()           This method is called on a Channel.connect(String)>Channel.connect(String) 55 .
void	stop()           This method is called on a Channel.disconnect()>Channel.disconnect() 55 .
void	up(org.jgroups.Event evt)           An event was received from the layer below.

 

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getName, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, isTrace, isWarn, passDown, passUp, printStats, providedDownServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setTrace, setUpProtocol, setWarn, startDownHandler, startUpHandler, statsEnabled, stopInternal, upThreadEnabled

 

Methods inherited from class java.lang.Object

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

 

Field Detail

members

final java.util.Vector members

---

members_set

final java.util.Set members_set

---

local_addr

org.jgroups.Address local_addr

---

group_addr

java.lang.String group_addr

---

timeout

long timeout

---

num_initial_members

int num_initial_members

---

is_server

boolean is_server

---

ping_waiter

PingWaiter ping_waiter

---

num_ping_requests

int num_ping_requests

Number of GET_MBRS_REQ messages to be sent (min=1), distributed over timeout ms

---

num_discovery_requests

int num_discovery_requests

Constructor Detail

Discovery

public Discovery()

Method Detail

localAddressSet

public void localAddressSet(org.jgroups.Address addr)

Called after local_addr was set

---

sendGetMembersRequest

public abstract void sendGetMembersRequest()

---

handleConnectOK

public void handleConnectOK()

Called when CONNECT_OK has been received

---

handleDisconnect

public void handleDisconnect()

---

handleConnect

public void handleConnect()

---

getTimeout

public long getTimeout()

---

setTimeout

public void setTimeout(long timeout)

---

getNumInitialMembers

public int getNumInitialMembers()

---

setNumInitialMembers

public void setNumInitialMembers(int num_initial_members)

---

getNumPingRequests

public int getNumPingRequests()

---

setNumPingRequests

public void setNumPingRequests(int num_ping_requests)

---

getNumberOfDiscoveryRequestsSent

public int getNumberOfDiscoveryRequestsSent()

---

providedUpServices

public java.util.Vector providedUpServices()

Description copied from class: org.jgroups.stack.Protocol

List of events that are provided to layers above (they will be handled when sent down from above).

---

setProperties

public boolean setProperties(java.util.Properties props)

sets the properties of the PING protocol. The following properties are available property: timeout - the timeout (ms) to wait for the initial members, default is 3000=3 secs property: num_initial_members - the minimum number of initial members for a FIND_INITAL_MBRS, default is 2

---

resetStats

public void resetStats()

---

start

public void start()
           throws java.lang.Exception

Description copied from class: org.jgroups.stack.Protocol

This method is called on a Channel.connect(String)>Channel.connect(String) 55 . 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.

---

stop

public void stop()

Description copied from class: org.jgroups.stack.Protocol

This method is called on a Channel.disconnect()>Channel.disconnect() 55 . 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

---

findInitialMembers

public java.util.Vector findInitialMembers()

Finds the initial membership

---

findInitialMembersAsString

public java.lang.String findInitialMembersAsString()

---

up

public void up(org.jgroups.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.

For the PING protocol, the Up operation does the following things. 1. If the event is a Event.MSG then PING will inspect the message header. If the header is null, PING simply passes up the event If the header is PingHeader.GET_MBRS_REQ then the PING protocol will PassDown a PingRequest message If the header is PingHeader.GET_MBRS_RSP we will add the message to the initial members vector and wake up any waiting threads. 2. If the event is Event.SET_LOCAL_ADDR we will simple set the local address of this protocol 3. For all other messages we simple pass it up to the protocol above

---

down

public void down(org.jgroups.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(). The PING protocol is interested in several different down events, Event.FIND_INITIAL_MBRS - sent by the GMS layer and expecting a GET_MBRS_OK Event.TMP_VIEW and Event.VIEW_CHANGE - a view change event Event.BECOME_SERVER - called after client has joined and is fully working group member Event.CONNECT, Event.DISCONNECT.

---

makeView

protected org.jgroups.View makeView(java.util.Vector mbrs)

---

Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> jgroups >> [ protocols overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---