Package org.jgroups.protocols
Class PING
- java.lang.Object
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- org.jgroups.stack.Protocol
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- org.jgroups.protocols.Discovery
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- org.jgroups.protocols.PING
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- 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
- Version:
- $Id: PING.java,v 1.36.2.5 2008/12/08 13:18:49 belaban Exp $
- Author:
- Bela Ban
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Constructor Summary
Constructors Constructor Description PING()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
getGossipPort()
long
getGossipRefresh()
java.lang.String
getName()
void
handleConnect()
void
handleDisconnect()
void
init()
Called after instance has been created (null constructor) and before protocol is started.void
localAddressSet(Address addr)
Called after local_addr was setvoid
sendGetMembersRequest()
void
setGossipPort(int gossip_port)
void
setGossipRefresh(long gossip_refresh)
boolean
setProperties(java.util.Properties props)
sets the properties of the PING protocol.void
stop()
This method is called on aChannel.disconnect()
.java.lang.Object
up(Event evt)
An event was received from the layer below.protected void
waitForDiscoveryRequestReception()
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Methods inherited from class org.jgroups.protocols.Discovery
down, findInitialMembers, findInitialMembersAsString, getNumberOfDiscoveryRequestsSent, getNumInitialMembers, getNumPingRequests, getTimeout, makeView, providedUpServices, resetStats, setNumInitialMembers, setNumPingRequests, setTimeout, start
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Methods inherited from class org.jgroups.stack.Protocol
destroy, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getProperties, getProtocolStack, getThreadFactory, getTransport, getUpProtocol, printStats, providedDownServices, requiredDownServices, requiredUpServices, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, statsEnabled, upThreadEnabled
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Field Detail
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discovery_reception
protected final Promise<java.lang.Boolean> discovery_reception
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name
public static final java.lang.String name
- See Also:
- Constant Field Values
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Method Detail
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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 classDiscovery
- 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
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getGossipPort
public int getGossipPort()
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setGossipPort
public void setGossipPort(int gossip_port)
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getGossipRefresh
public long getGossipRefresh()
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setGossipRefresh
public void setGossipRefresh(long gossip_refresh)
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init
public void init() throws java.lang.Exception
Description copied from class:Protocol
Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
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stop
public void stop()
Description copied from class:Protocol
This method is called on aChannel.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
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localAddressSet
public void localAddressSet(Address addr)
Description copied from class:Discovery
Called after local_addr was set- Overrides:
localAddressSet
in classDiscovery
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handleConnect
public void handleConnect()
- Overrides:
handleConnect
in classDiscovery
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handleDisconnect
public void handleDisconnect()
- Overrides:
handleDisconnect
in classDiscovery
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sendGetMembersRequest
public void sendGetMembersRequest()
- Specified by:
sendGetMembersRequest
in classDiscovery
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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 usingPassDown
or c) the event (or another event) is sent up the stack usingPassUp
. 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
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waitForDiscoveryRequestReception
protected void waitForDiscoveryRequestReception()
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