org.apache.flink.runtime.leaderelection

类 DefaultLeaderElectionService

java.lang.Object

org.apache.flink.runtime.leaderelection.DefaultLeaderElectionService

所有已实现的接口:

LeaderElectionEventHandler, LeaderElectionService

public class DefaultLeaderElectionService
extends Object
implements LeaderElectionService, LeaderElectionEventHandler

Default implementation for leader election service. Composed with different LeaderElectionDriver, we could perform a leader election for the contender, and then persist the leader information to various storage.

构造器概要

构造器

构造器和说明
DefaultLeaderElectionService(LeaderElectionDriverFactory leaderElectionDriverFactory)

方法概要

限定符和类型	方法和说明
void	confirmLeadership(UUID leaderSessionID, String leaderAddress) Confirms that the LeaderContender has accepted the leadership identified by the given leader session id.
UUID	getLeaderSessionID() Returns the current leader session ID or null, if the contender is not the leader.
boolean	hasLeadership(UUID leaderSessionId) Returns true if the LeaderContender with which the service has been started owns currently the leadership under the given leader session id.
void	onGrantLeadership(UUID newLeaderSessionId) Called by specific LeaderElectionDriver when the leadership is granted.
void	onLeaderInformationChange(LeaderInformation leaderInformation) Called by specific LeaderElectionDriver when the leader information is changed.
void	onRevokeLeadership() Called by specific LeaderElectionDriver when the leadership is revoked.
void	start(LeaderContender contender) Starts the leader election service.
void	stop() Stops the leader election service.

从类继承的方法 java.lang.Object

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

构造器详细资料

DefaultLeaderElectionService

public DefaultLeaderElectionService(LeaderElectionDriverFactory leaderElectionDriverFactory)

方法详细资料

start

public final void start(LeaderContender contender)
                 throws Exception

从接口复制的说明: LeaderElectionService

Starts the leader election service. This method can only be called once.

指定者:

start 在接口中 LeaderElectionService

参数:

contender - LeaderContender which applies for the leadership

抛出:

Exception

stop

public final void stop()
                throws Exception

从接口复制的说明: LeaderElectionService

Stops the leader election service.

指定者:

stop 在接口中 LeaderElectionService

抛出:

Exception

confirmLeadership

public void confirmLeadership(UUID leaderSessionID,
                              String leaderAddress)

从接口复制的说明: LeaderElectionService

Confirms that the LeaderContender has accepted the leadership identified by the given leader session id. It also publishes the leader address under which the leader is reachable.

The rational behind this method is to establish an order between setting the new leader session ID in the LeaderContender and publishing the new leader session ID as well as the leader address to the leader retrieval services.

指定者:

confirmLeadership 在接口中 LeaderElectionService

参数:

leaderSessionID - The new leader session ID

leaderAddress - The address of the new leader

hasLeadership

public boolean hasLeadership(@Nonnull
                             UUID leaderSessionId)

从接口复制的说明: LeaderElectionService

Returns true if the LeaderContender with which the service has been started owns currently the leadership under the given leader session id.

指定者:

hasLeadership 在接口中 LeaderElectionService

参数:

leaderSessionId - identifying the current leader

返回:

true if the associated LeaderContender is the leader, otherwise false

getLeaderSessionID

@VisibleForTesting
 @Nullable
public UUID getLeaderSessionID()

Returns the current leader session ID or null, if the contender is not the leader.

返回:

The last leader session ID or null, if the contender is not the leader

onGrantLeadership

public void onGrantLeadership(UUID newLeaderSessionId)

从接口复制的说明: LeaderElectionEventHandler

Called by specific LeaderElectionDriver when the leadership is granted.

指定者:

onGrantLeadership 在接口中 LeaderElectionEventHandler

参数:

newLeaderSessionId - the valid leader session id

onRevokeLeadership

public void onRevokeLeadership()

从接口复制的说明: LeaderElectionEventHandler

Called by specific LeaderElectionDriver when the leadership is revoked.

指定者:

onRevokeLeadership 在接口中 LeaderElectionEventHandler

onLeaderInformationChange

public void onLeaderInformationChange(LeaderInformation leaderInformation)

从接口复制的说明: LeaderElectionEventHandler

Called by specific LeaderElectionDriver when the leader information is changed. Then the LeaderElectionService could write the leader information again if necessary. This method should only be called when LeaderElectionDriver.hasLeadership() is true. Duplicated leader change events could happen, so the implementation should check whether the passed leader information is really different with internal confirmed leader information.

指定者:

onLeaderInformationChange 在接口中 LeaderElectionEventHandler

参数:

leaderInformation - leader information which contains leader session id and leader address.