org.jgroups.protocols

Class PING

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.Discovery

org.jgroups.protocols.PING

Direct Known Subclasses:

BPING, MPING

public class PING
extends Discovery

The PING protocol retrieves the initial membership by mcasting a discovery request (via the multicast capable transport) to all current cluster members

The responses should allow us to determine the coordinator which 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 discovery requests with a discovery response.

Author:

Bela Ban

Nested Class Summary

Nested classes/interfaces inherited from class org.jgroups.protocols.Discovery

Discovery.DiscoveryCacheDisseminationTask

Field Summary

Fields inherited from class org.jgroups.protocols.Discovery

always_send_physical_addr_with_discovery_request, async_discovery, async_discovery_use_separate_thread_per_request, break_on_coord_rsp, cluster_name, current_coord, discovery_rsp_expiry_time, force_sending_discovery_rsps, is_coord, is_leaving, is_server, local_addr, max_members_in_discovery_request, members, num_discovery_requests, num_initial_members, num_initial_srv_members, ping_responses, return_entire_cache, send_cache_on_join, stagger_timeout, timeout, timer, transport_supports_multicasting, use_disk_cache, view, WHITESPACE

Fields inherited from class org.jgroups.stack.Protocol

after_creation_hook, down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

Constructors

Constructor and Description
PING()

Method Summary

Modifier and Type	Method and Description
void	findMembers(java.util.List<Address> members, boolean initial_discovery, Responses responses) Fetches information (e.g.
boolean	isDynamic()
protected void	sendDiscoveryRequest(java.lang.String cluster_name, java.util.List<Address> members_to_find)
protected void	sendMcastDiscoveryRequest(Message msg)

Methods inherited from class org.jgroups.protocols.Discovery

addDiscoveryResponseToCaches, addResponse, addressAsString, addToCache, breakOnCoordResponse, breakOnCoordResponse, deserialize, discoveryRequestReceived, discoveryRspExpiryTime, disseminateDiscoveryInformation, down, dumpCache, findInitialMembersAsString, findMembers, forceDiscoveryResponses, forceDiscoveryResponses, getCurrentCoord, getNumberOfDiscoveryRequestsSent, getNumInitialMembers, getTimeout, getView, getViewId, handleConnect, handleDisconnect, handleDiscoveryResponse, init, isCoord, isMergeRunning, marshal, numInitialMembers, numInitialMembers, providedUpServices, read, readPingData, resetStats, returnEntireCache, returnEntireCache, sendCacheInformation, sendDiscoveryResponse, serializeWithoutView, setForceSendingDiscoveryRsps, setNumInitialMembers, setTimeout, staggerTimeout, staggerTimeout, start, startCacheDissemination, stop, timeout, timeout, up, useDiskCache, useDiskCache, weedOutCompletedDiscoveryResponses, write

Methods inherited from class org.jgroups.stack.Protocol

accept, afterCreationHook, destroy, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, printStats, providedDownServices, requiredDownServices, requiredUpServices, resetStatistics, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled, up

Methods inherited from class java.lang.Object

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

Constructor Detail

PING

public PING()

Method Detail

isDynamic

public boolean isDynamic()

Specified by:

isDynamic in class Discovery

findMembers

public void findMembers(java.util.List<Address> members,
                        boolean initial_discovery,
                        Responses responses)

Description copied from class: Discovery

Fetches information (e.g. physical address, logical name) for the given member addresses. Needs to add responses to the Responses object. If Discovery.async_discovery is true, this method will be called in a separate thread, otherwise the caller's thread will be used.

Specified by:

findMembers in class Discovery

Parameters:

members - A list of logical addresses (typically UUIDs). If null, then information for all members is fetched

initial_discovery - Set to true if this is for the initial membership discovery. Some protocols (e.g. file based ones) may return only the information for the coordinator(s).

responses - The list to which responses should be added

sendDiscoveryRequest

protected void sendDiscoveryRequest(java.lang.String cluster_name,
                                    java.util.List<Address> members_to_find)
                             throws java.lang.Exception

Throws:

java.lang.Exception

sendMcastDiscoveryRequest

protected void sendMcastDiscoveryRequest(Message msg)