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java.lang.Objectorg.jgroups.stack.Protocol
org.jgroups.protocols.Discovery
public abstract class Discovery
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
Nested Class Summary | |
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protected static class |
Discovery.Responses
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Field Summary | |
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protected java.lang.String |
group_addr
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protected Address |
local_addr
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protected java.util.Vector<Address> |
members
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protected java.util.Set<Discovery.Responses> |
ping_responses
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protected int |
rank
|
protected TimeScheduler |
timer
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protected View |
view
|
Fields inherited from class org.jgroups.stack.Protocol |
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down_prot, ergonomics, id, log, name, stack, stats, up_prot |
Constructor Summary | |
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Discovery()
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Method Summary | |
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void |
discoveryRequestReceived(Address sender,
java.lang.String logical_name,
java.util.Collection<PhysicalAddress> physical_addrs)
|
java.lang.Object |
down(Event evt)
An event is to be sent down the stack. |
java.util.List<PingData> |
findAllMembers(Promise<JoinRsp> promise)
|
java.util.List<View> |
findAllViews(Promise<JoinRsp> promise)
Finds the views: sends a GET_MBRS_REQ to all members, waits 'timeout' ms or until 'num_initial_members' have been retrieved |
java.lang.String |
findAllViewsAsString()
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java.util.List<PingData> |
findInitialMembers(Promise<JoinRsp> promise)
Finds initial members |
protected java.util.List<PingData> |
findInitialMembers(Promise<JoinRsp> promise,
int num_expected_rsps,
boolean break_on_coord,
boolean return_views_only)
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java.lang.String |
findInitialMembersAsString()
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int |
getNumberOfDiscoveryRequestsSent()
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int |
getNumInitialMembers()
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int |
getNumPingRequests()
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long |
getTimeout()
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java.lang.String |
getView()
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void |
handleConnect()
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void |
handleDisconnect()
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void |
init()
Called after instance has been created (null constructor) and before protocol is started. |
protected View |
makeView(java.util.Vector<Address> mbrs)
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java.util.Vector<java.lang.Integer> |
providedUpServices()
List of events that are provided to layers above (they will be handled when sent down from above). |
void |
resetStats()
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abstract void |
sendGetMembersRequest(java.lang.String cluster_name,
Promise promise,
boolean return_views_only)
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void |
setNumInitialMembers(int num_initial_members)
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void |
setNumPingRequests(int num_ping_requests)
|
void |
setTimeout(long timeout)
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void |
start()
This method is called on a Channel.connect(String) . |
void |
stop()
This method is called on a Channel.disconnect() . |
java.lang.Object |
up(Event evt)
An event was received from the layer below. |
Methods inherited from class org.jgroups.stack.Protocol |
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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 |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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protected int rank
protected TimeScheduler timer
protected View view
protected final java.util.Vector<Address> members
protected Address local_addr
protected java.lang.String group_addr
protected final java.util.Set<Discovery.Responses> ping_responses
Constructor Detail |
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public Discovery()
Method Detail |
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public void init() throws java.lang.Exception
Protocol
init
in class Protocol
java.lang.Exception
- Thrown if protocol cannot be initialized successfully. This will cause the
ProtocolStack to fail, so the channel constructor will throw an exceptionpublic abstract void sendGetMembersRequest(java.lang.String cluster_name, Promise promise, boolean return_views_only) throws java.lang.Exception
java.lang.Exception
public void handleDisconnect()
public void handleConnect()
public void discoveryRequestReceived(Address sender, java.lang.String logical_name, java.util.Collection<PhysicalAddress> physical_addrs)
public long getTimeout()
public void setTimeout(long timeout)
public int getNumInitialMembers()
public void setNumInitialMembers(int num_initial_members)
public int getNumPingRequests()
public void setNumPingRequests(int num_ping_requests)
public int getNumberOfDiscoveryRequestsSent()
public java.lang.String getView()
public java.util.Vector<java.lang.Integer> providedUpServices()
Protocol
providedUpServices
in class Protocol
public void resetStats()
resetStats
in class Protocol
public void start() throws java.lang.Exception
Protocol
Channel.connect(String)
. Starts work.
Protocols are connected and queues are ready to receive events.
Will be called from bottom to top. This call will replace
the START and START_OK events.
start
in class Protocol
java.lang.Exception
- Thrown if protocol cannot be started successfully. This will cause the ProtocolStack
to fail, so Channel.connect(String)
will throw an exceptionpublic void stop()
Protocol
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
stop
in class Protocol
public java.util.List<View> findAllViews(Promise<JoinRsp> promise)
public java.util.List<PingData> findInitialMembers(Promise<JoinRsp> promise)
promise
-
public java.util.List<PingData> findAllMembers(Promise<JoinRsp> promise)
protected java.util.List<PingData> findInitialMembers(Promise<JoinRsp> promise, int num_expected_rsps, boolean break_on_coord, boolean return_views_only)
public java.lang.String findInitialMembersAsString()
public java.lang.String findAllViewsAsString()
public java.lang.Object up(Event evt)
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
up
in class Protocol
evt
- - the event that has been sent from the layer belowpublic java.lang.Object down(Event evt)
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 up_prot.up()
.
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.
down
in class Protocol
protected final View makeView(java.util.Vector<Address> mbrs)
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