org.apache.flink.runtime.webmonitor.retriever

Class LeaderRetriever

java.lang.Object

org.apache.flink.runtime.webmonitor.retriever.LeaderRetriever

All Implemented Interfaces:

LeaderRetrievalListener

Direct Known Subclasses:

LeaderGatewayRetriever

public class LeaderRetriever
extends Object
implements LeaderRetrievalListener

Retrieves and stores the current leader address.

Field Summary

Fields

Modifier and Type	Field and Description
protected org.slf4j.Logger	log

Constructor Summary

Constructors

Constructor and Description
LeaderRetriever()

Method Summary

Modifier and Type	Method and Description
CompletableFuture<Tuple2<String,UUID>>	getLeaderFuture() Returns the current JobManagerGateway future.
Optional<Tuple2<String,UUID>>	getLeaderNow() Returns the current leader information if available.
void	handleError(Exception exception) This method is called by the LeaderRetrievalService in case of an exception.
void	notifyLeaderAddress(String leaderAddress, UUID leaderSessionID) This method is called by the LeaderRetrievalService when a new leader is elected.
protected void	notifyNewLeaderAddress(CompletableFuture<Tuple2<String,UUID>> newLeaderAddressFuture)

Methods inherited from class java.lang.Object

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

Field Detail

log

protected final org.slf4j.Logger log

Constructor Detail

LeaderRetriever

public LeaderRetriever()

Method Detail

getLeaderNow

public Optional<Tuple2<String,UUID>> getLeaderNow()
                                           throws Exception

Returns the current leader information if available. Otherwise it returns an empty optional.

Returns:

The current leader information if available. Otherwise it returns an empty optional.

Throws:

Exception - if the leader future has been completed with an exception

getLeaderFuture

public CompletableFuture<Tuple2<String,UUID>> getLeaderFuture()

Returns the current JobManagerGateway future.

notifyLeaderAddress

public void notifyLeaderAddress(String leaderAddress,
                                UUID leaderSessionID)

Description copied from interface: LeaderRetrievalListener

This method is called by the LeaderRetrievalService when a new leader is elected.

If both arguments are null then it signals that leadership was revoked without a new leader having been elected.

Specified by:

notifyLeaderAddress in interface LeaderRetrievalListener

Parameters:

leaderAddress - The address of the new leader

leaderSessionID - The new leader session ID

handleError

public void handleError(Exception exception)

Description copied from interface: LeaderRetrievalListener

This method is called by the LeaderRetrievalService in case of an exception. This assures that the LeaderRetrievalListener is aware of any problems occurring in the LeaderRetrievalService thread.

Specified by:

handleError in interface LeaderRetrievalListener

notifyNewLeaderAddress

protected void notifyNewLeaderAddress(CompletableFuture<Tuple2<String,UUID>> newLeaderAddressFuture)