org.apache.flink.runtime.leaderelection

Class LeaderInformationRegister

java.lang.Object

org.apache.flink.runtime.leaderelection.LeaderInformationRegister

public class LeaderInformationRegister
extends Object

A register containing the LeaderInformation for multiple contenders based on their componentId. No empty LeaderInformation is stored physically. No entry and an entry with an empty LeaderInformation are, therefore, semantically the same.

Constructor Summary

Constructors

Constructor and Description
LeaderInformationRegister(Map<String,LeaderInformation> leaderInformationPerComponentId) Creates a LeaderInformationRegister based on the passed leader information.

Method Summary

Modifier and Type	Method and Description
static LeaderInformationRegister	clear(LeaderInformationRegister leaderInformationRegister, String componentId) Creates a new LeaderInformationRegister that matches the passed LeaderInformationRegister except for the entry of componentId which is removed if it existed.
static LeaderInformationRegister	empty()
Optional<LeaderInformation>	forComponentId(String componentId) Returns the LeaderInformation that is stored or an empty Optional if no entry exists for the passed componentId.
LeaderInformation	forComponentIdOrEmpty(String componentId) Returns a LeaderInformation which is empty if no LeaderInformation is stored for the passed componentId.
Iterable<String>	getRegisteredComponentIds() Returns the componentIds for which leader information is stored.
boolean	hasLeaderInformation(String componentId) Checks whether the register holds non-empty LeaderInformation for the passed componentId.
boolean	hasNoLeaderInformation() Checks that no non-empty LeaderInformation is stored.
static LeaderInformationRegister	merge(LeaderInformationRegister leaderInformationRegister, String componentId, LeaderInformation leaderInformation) Merges another LeaderInformationRegister with additional leader information into a new LeaderInformationRegister instance.
static LeaderInformationRegister	of(String componentId, LeaderInformation leaderInformation) Creates a single-entry instance containing only the passed information.

Methods inherited from class java.lang.Object

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

Constructor Detail

LeaderInformationRegister

public LeaderInformationRegister(Map<String,LeaderInformation> leaderInformationPerComponentId)

Creates a LeaderInformationRegister based on the passed leader information.

Method Detail

empty

public static LeaderInformationRegister empty()

of

public static LeaderInformationRegister of(String componentId,
                                           LeaderInformation leaderInformation)

Creates a single-entry instance containing only the passed information.

merge

public static LeaderInformationRegister merge(@Nullable
                                              LeaderInformationRegister leaderInformationRegister,
                                              String componentId,
                                              LeaderInformation leaderInformation)

Merges another LeaderInformationRegister with additional leader information into a new LeaderInformationRegister instance. Any existing LeaderInformation for the passed componentId will be overwritten.

Empty LeaderInformation results in the removal of the corresponding entry (if it exists).

clear

public static LeaderInformationRegister clear(@Nullable
                                              LeaderInformationRegister leaderInformationRegister,
                                              String componentId)

Creates a new LeaderInformationRegister that matches the passed LeaderInformationRegister except for the entry of componentId which is removed if it existed.

forComponentId

public Optional<LeaderInformation> forComponentId(String componentId)

Returns the LeaderInformation that is stored or an empty Optional if no entry exists for the passed componentId.

forComponentIdOrEmpty

public LeaderInformation forComponentIdOrEmpty(String componentId)

Returns a LeaderInformation which is empty if no LeaderInformation is stored for the passed componentId.

getRegisteredComponentIds

public Iterable<String> getRegisteredComponentIds()

Returns the componentIds for which leader information is stored.

hasLeaderInformation

public boolean hasLeaderInformation(String componentId)

Checks whether the register holds non-empty LeaderInformation for the passed componentId.

hasNoLeaderInformation

public boolean hasNoLeaderInformation()

Checks that no non-empty LeaderInformation is stored.

Returns:

true, if there is no entry that refers to a non-empty LeaderInformation; otherwise false (i.e. either no information is stored under any componentId or there are entries for certain componentIds that refer to an empty LeaderInformation record).