io.atomix.coordination

Interface GroupMember

All Known Subinterfaces:

LocalGroupMember

public interface GroupMember

Provides an interface to interacting with members of a DistributedGroup.

A GroupMember represents a reference to a single instance of a resource which has joined a membership group. Each member is guaranteed to have a unique id() throughout the lifetime of the distributed resource. Group members can schedule or execute callbacks remotely on member nodes.

Author:

Method Summary

Modifier and Type	Method and Description
CompletableFuture<Void>	execute(Runnable callback) Executes a callback on the group member.
<T> CompletableFuture<T>	get(String property) Gets the value of a property of the member.
String	id() Returns the member ID.
boolean	isLeader() Returns a boolean value indicating whether this member is the current leader.
CompletableFuture<Void>	schedule(Duration delay, Runnable callback) Schedules a callback to run after the given delay on the member.
CompletableFuture<Void>	schedule(Instant instant, Runnable callback) Schedules a callback to run at the given instant.
CompletableFuture<Void>	send(String topic, Object message) Sends a message to the member.

Method Detail

id

String id()

Returns the member ID.

Returns:

The member ID.

isLeader

boolean isLeader()

Returns a boolean value indicating whether this member is the current leader.

Returns:

Indicates whether this member is the current leader.

get

<T> CompletableFuture<T> get(String property)

Gets the value of a property of the member.

Properties are identified by a String name. Properties may only be set by the local member but can be accessed by any instance of the DistributedGroup.

Type Parameters:

T - The property type.

Parameters:

property - The property to get.

Returns:

A completable future to be completed with the value of the property.

send

CompletableFuture<Void> send(String topic,
                             Object message)

Sends a message to the member.

Group messaging guarantees sequential consistency such that members are guaranteed to receive messages in the order in which they were sent. Messages will be sent according to the parent DistributedGroup's consistency level. If the consistency level is Consistency (the default), the returned CompletableFuture will be completed once the member has received the message or has left the group. Note that the completion of the returned future does not necessarily guarantee that the message was received and processed, only that it was either received and processed or the member left the group or disconnected.

Parameters:

topic - The message topic.

message - The message to send.

Returns:

A completable future to be completed once the message has been received by the member.

schedule

CompletableFuture<Void> schedule(Instant instant,
                                 Runnable callback)

Schedules a callback to run at the given instant.

Parameters:

instant - The instant at which to run the callback.

callback - The callback to run.

Returns:

A completable future to be completed once the callback has been scheduled.

schedule

CompletableFuture<Void> schedule(Duration delay,
                                 Runnable callback)

Schedules a callback to run after the given delay on the member.

Parameters:

delay - The delay after which to run the callback.

callback - The callback to run.

Returns:

A completable future to be completed once the callback has been scheduled.

execute

CompletableFuture<Void> execute(Runnable callback)

Executes a callback on the group member.

Parameters:

callback - The callback to execute.

Returns:

A completable future to be completed once the callback has completed.