org.jgroups.protocols

Class PING

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.Discovery

org.jgroups.protocols.PING

Direct Known Subclasses:

MPING

public class PING
extends Discovery

The PING 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 mcasting PING requests to an IP MCAST address (or, if gossiping is enabled, by contacting the GossipRouter). 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 property: gossip_host - if you are using GOSSIP then this defines the host of the GossipRouter, default is null property: gossip_port - if you are using GOSSIP then this defines the port of the GossipRouter, default is null

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	name

Fields inherited from class org.jgroups.stack.Protocol

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

Constructor Summary

Constructors

Constructor and Description
PING()

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.String	getName()
void	handleConnect()
void	handleDisconnect()
void	localAddressSet(Address addr) Called after local_addr was set
void	sendGetMembersRequest()
boolean	setProperties(java.util.Properties props) sets the properties of the PING protocol.
void	stop() This method is called on a Channel.disconnect().

Methods inherited from class org.jgroups.protocols.Discovery

down, findInitialMembers, findInitialMembersAsString, getNumberOfDiscoveryRequestsSent, getNumInitialMembers, getNumPingRequests, getTimeout, handleConnectOK, makeView, providedUpServices, resetStats, setNumInitialMembers, setNumPingRequests, setTimeout, start, up

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, passDown, passUp, printStats, providedDownServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setUpProtocol, 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

name

public static final java.lang.String name

See Also:

Constant Field Values

Constructor Detail

PING

public PING()

Method Detail

getName

public java.lang.String getName()

Specified by:

getName in class Protocol

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 property: gossip_host - if you are using GOSSIP then this defines the host of the GossipRouter, default is null property: gossip_port - if you are using GOSSIP then this defines the port of the GossipRouter, default is null

Overrides:

setProperties in class Discovery

Parameters:

props - - a property set containing only PING properties

Returns:

returns true if all properties were parsed properly returns false if there are unrecnogized properties in the property set

stop

public void stop()

Description copied from class: 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

Overrides:

stop in class Discovery

localAddressSet

public void localAddressSet(Address addr)

Description copied from class: Discovery

Called after local_addr was set

Overrides:

localAddressSet in class Discovery

handleConnect

public void handleConnect()

Overrides:

handleConnect in class Discovery

handleDisconnect

public void handleDisconnect()

Overrides:

handleDisconnect in class Discovery

sendGetMembersRequest

public void sendGetMembersRequest()

Specified by:

sendGetMembersRequest in class Discovery