| java.lang.Object
 java.lang.Thread
org.jgroups.stack.UpHandler
org.jgroups.protocols.Discovery
All known Subclasses: org.jgroups.protocols.WANPING, org.jgroups.protocols.TCPPING, org.jgroups.protocols.PING, org.jgroups.protocols.TCPGOSSIP,
| Discovery | | abstract public class Discovery extends Protocol (Code) | | 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 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
- 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
author:
Bela Ban
version:
$Id: Discovery.java,v 1.16.2.1 2007/04/27 08:03:51 belaban Exp $ |
| is_server | | boolean is_server(Code) | | |
| num_discovery_requests | | int num_discovery_requests(Code) | | |
| num_initial_members | | int num_initial_members(Code) | | |
| num_ping_requests | | int num_ping_requests(Code) | | Number of GET_MBRS_REQ messages to be sent (min=1), distributed over timeout ms
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| down | | public void down(Event evt)(Code) | | 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.
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| findInitialMembers | | public Vector findInitialMembers()(Code) | | Finds the initial membership
Vector |
| findInitialMembersAsString | | public String findInitialMembersAsString()(Code) | | |
| getNumInitialMembers | | public int getNumInitialMembers()(Code) | | |
| getNumPingRequests | | public int getNumPingRequests()(Code) | | |
| getNumberOfDiscoveryRequestsSent | | public int getNumberOfDiscoveryRequestsSent()(Code) | | |
| getTimeout | | public long getTimeout()(Code) | | |
| handleConnect | | public void handleConnect()(Code) | | |
| handleConnectOK | | public void handleConnectOK()(Code) | | Called when CONNECT_OK has been received
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| handleDisconnect | | public void handleDisconnect()(Code) | | |
| localAddressSet | | public void localAddressSet(Address addr)(Code) | | Called after local_addr was set
|
| resetStats | | public void resetStats()(Code) | | |
| sendGetMembersRequest | | abstract public void sendGetMembersRequest()(Code) | | |
| setNumInitialMembers | | public void setNumInitialMembers(int num_initial_members)(Code) | | |
| setNumPingRequests | | public void setNumPingRequests(int num_ping_requests)(Code) | | |
| setProperties | | public boolean setProperties(Properties props)(Code) | | 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
Parameters:
props - - a property set returns true if all properties were parsed properlyreturns false if there are unrecnogized properties in the property set |
| setTimeout | | public void setTimeout(long timeout)(Code) | | |
| up | | public void up(Event evt)(Code) | | 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
Parameters:
evt - - the event that has been sent from the layer below |
| Fields inherited from org.jgroups.stack.UpHandler | final protected Log log(Code)(Java Doc)
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