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 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.
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.
- Author:
- Bela Ban
Constructor Summary |
PING()
|
Methods inherited from class org.jgroups.protocols.Discovery |
discoveryRequestReceived, down, findAllMembers, findAllViews, findAllViewsAsString, findInitialMembers, findInitialMembers, findInitialMembersAsString, getNumberOfDiscoveryRequestsSent, getNumInitialMembers, getNumPingRequests, getTimeout, getView, handleConnect, handleDisconnect, init, makeView, providedUpServices, resetStats, setNumInitialMembers, setNumPingRequests, setTimeout, start |
Methods inherited from class org.jgroups.stack.Protocol |
destroy, downThreadEnabled, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getId, getLevel, getName, getProperties, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getValue, isErgonomics, printStats, providedDownServices, requiredDownServices, requiredUpServices, setDownProtocol, setErgonomics, setId, setLevel, setProperties, setPropertiesInternal, setProperty, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled, upThreadEnabled |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
discovery_reception
protected final Promise<java.lang.Boolean> discovery_reception
PING
public PING()
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
sendGetMembersRequest
public void sendGetMembersRequest(java.lang.String cluster_name,
Promise promise,
boolean return_views_only)
throws java.lang.Exception
- Specified by:
sendGetMembersRequest
in class Discovery
- Throws:
java.lang.Exception
up
public java.lang.Object up(Event evt)
- Description copied from class:
Discovery
- 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
- Overrides:
up
in class Discovery
- Parameters:
evt
- - the event that has been sent from the layer below
waitForDiscoveryRequestReception
protected void waitForDiscoveryRequestReception()
Copyright © 1998-2009 Bela Ban / Red Hat. All Rights Reserved.