Member (Copycat API Reference (1.1.4))

Nested Classes
Modifier and Type	Interface and Description
`static class`	`Member.Status` Indicates the availability of a member from the perspective of the cluster `leader`.
`static class`	`Member.Type` Indicates how the member participates in voting and replication.

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`Address`	`address()` Returns the member server address.
`Address`	`clientAddress()` Returns the member client address.
`CompletableFuture<Void>`	`demote()` Demotes the member to the next lowest type.
`CompletableFuture<Void>`	`demote(Member.Type type)` Demotes the member to the given type.
`int`	`id()` Returns the member ID.
`Listener<Member.Status>`	`onStatusChange(Consumer<Member.Status> callback)` Registers a callback to be called when the member's status changes.
`Listener<Member.Type>`	`onTypeChange(Consumer<Member.Type> callback)` Registers a callback to be called when the member's type changes.
`CompletableFuture<Void>`	`promote()` Promotes the member to the next highest type.
`CompletableFuture<Void>`	`promote(Member.Type type)` Promotes the member to the given type.
`CompletableFuture<Void>`	`remove()` Removes the member from the configuration.
`Address`	`serverAddress()` Returns the member server address.
`Member.Status`	`status()` Returns the member status.
`Member.Type`	`type()` Returns the member type.
`Instant`	`updated()` Returns the time at which the member was updated.

```
public interface Member
```
Represents a member of a Copycat cluster.
This interface provides metadata and operations related to a specific member of a Copycat cluster. Each server in a Cluster has a view of the cluster state and can reference and operate on specific members of the cluster via this API.
Each member in the cluster has an associated Member.Type and Member.Status. The Member.Type is indicative of the manner in which the member interacts with other members of the cluster. The Member.Status is indicative of the leader's ability to communicate with the member. Additionally, each member is identified by an address and unique ID which is generated from the Address hash code. The member's Address represents the address through which the server communicates with other servers and not through which clients communicate with the member (which may be a different Address).
Users can listen for Member.Type and Member.Status changes via the onTypeChange(Consumer) and onStatusChange(Consumer) methods respectively. Member types can be modified by virtually any member of the cluster via the promote() and demote() methods. This allows servers to modify the way dead nodes interact with the cluster and modify the Raft quorum size without requiring the member being modified to be available. The member status is controlled only by the cluster leader. When the leader fails to contact a member for a few rounds of heartbeats, the leader will commit a configuration change marking that member as Member.Status.UNAVAILABLE. Once the member can be reached again, the leader will update its status back to Member.Status.AVAILABLE.
Author:
- Nested Class Summary
  
  Nested Classes
  Modifier and Type Interface and Description
  
  static class Member.Status
  Indicates the availability of a member from the perspective of the cluster leader.
  
  static class Member.Type
  Indicates how the member participates in voting and replication.
  
  Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method and Description
  
  Address address()
  Returns the member server address.
  
  Address clientAddress()
  Returns the member client address.
  
  CompletableFuture<Void> demote()
  Demotes the member to the next lowest type.
  
  CompletableFuture<Void> demote(Member.Type type)
  Demotes the member to the given type.
  
  int id()
  Returns the member ID.
  
  Listener<Member.Status> onStatusChange(Consumer<Member.Status> callback)
  Registers a callback to be called when the member's status changes.
  
  Listener<Member.Type> onTypeChange(Consumer<Member.Type> callback)
  Registers a callback to be called when the member's type changes.
  
  CompletableFuture<Void> promote()
  Promotes the member to the next highest type.
  
  CompletableFuture<Void> promote(Member.Type type)
  Promotes the member to the given type.
  
  CompletableFuture<Void> remove()
  Removes the member from the configuration.
  
  Address serverAddress()
  Returns the member server address.
  
  Member.Status status()
  Returns the member status.
  
  Member.Type type()
  Returns the member type.
  
  Instant updated()
  Returns the time at which the member was updated.

- Method Detail
  - id
```
int id()
```
    Returns the member ID.
    The member ID is calculated as the hash of the member's server Address and is therefore equivalent to the return value of Address.hashCode(). The member ID simply provides a more compact identifier to send on the wire when communicating between servers.
    
    Returns:
    
    The member ID.
  - address
```
Address address()
```
    Returns the member server address.
    This is the primary address through which servers in the cluster identify and communicate with one another. The server address is guaranteed to be unique to each member in the cluster.
    
    Returns:
    
    The member server address. This is the same address as serverAddress().
  - clientAddress
```
Address clientAddress()
```
    Returns the member client address.
    THis is the address through which clients communicate with the member. Depending on the member's configuration, the client address may or may not be the same as the serverAddress(), but it will always be non-null.
    
    Returns:
    
    The address to which the member binds for client communication.
  - serverAddress
```
Address serverAddress()
```
    Returns the member server address.
    The server address is the primary address through which servers in the cluster communicate with one another. The server address is guaranteed to be unique to each member in the cluster.
    
    Returns:
    
    The address to which the member binds for server communication.
  - type
```
Member.Type type()
```
    Returns the member type.
    The member type is indicative of the member's level of participation in the Raft consensus algorithm and asynchronous replication within the cluster. Member types may change throughout the lifetime of the cluster. Types can be changed by promoting or demoting the member. Member types for a given member are guaranteed to change in the same order on all nodes, but the type of a member may be different from the perspective of different nodes at any given time.
    
    Returns:
    
    The member type.
  - onTypeChange
```
Listener<Member.Type> onTypeChange(Consumer<Member.Type> callback)
```
    Registers a callback to be called when the member's type changes.
    The type change callback will be called when the local server receives notification of the change in type to this member. Type changes may occur at different times from the perspective of different servers but are guaranteed to occur in the same order on all servers.
    
    Parameters:
    
    callback - The callback to be called when the member's type changes.
    
    Returns:
    
    The member type change listener.
  - status
```
Member.Status status()
```
    Returns the member status.
    The status is indicative of the leader's ability to communicate with this member. If this member is a local member, the member's status will be Member.Status.AVAILABLE while the server is alive and will not change regardless of the leader's ability to communicate with the local member. Similarly, if the local server is partitioned from the leader then changes in statuses seen on other nodes may not be visible to this node. Status changes are guaranteed to occur in the same order on all nodes but without a real-time constraint.
    
    Returns:
    
    The member status.
  - updated
```
Instant updated()
```
    Returns the time at which the member was updated.
    The member update time is not guaranteed to be consistent across servers or consistent across server restarts. The update time is guaranteed to be monotonically increasing.
    
    Returns:
    
    The time at which the member was updated.
  - onStatusChange
```
Listener<Member.Status> onStatusChange(Consumer<Member.Status> callback)
```
    Registers a callback to be called when the member's status changes.
    The status change callback will be called when the local server receives notification of the change in status to this member. Status changes may occur at different times from the perspective of different servers but are guaranteed to occur in the same order on all servers.
    
    Parameters:
    
    callback - The callback to be called when the member's status changes.
    
    Returns:
    
    The member status change listener.
  - promote
```
CompletableFuture<Void> promote()
```
    Promotes the member to the next highest type.
    If the member is promoted to Member.Type.ACTIVE the Raft quorum size will increase.
    
    Returns:
    
    A completable future to be completed once the member has been promoted.
  - promote
```
CompletableFuture<Void> promote(Member.Type type)
```
    Promotes the member to the given type.
    If the member is promoted to Member.Type.ACTIVE the Raft quorum size will increase.
    
    Parameters:
    
    type - The type to which to promote the member.
    
    Returns:
    
    A completable future to be completed once the member has been promoted.
  - demote
```
CompletableFuture<Void> demote()
```
    Demotes the member to the next lowest type.
    If the member is an Member.Type.ACTIVE member then demoting it will impact the Raft quorum size.
    
    Returns:
    
    A completable future to be completed once the member has been demoted.
  - demote
```
CompletableFuture<Void> demote(Member.Type type)
```
    Demotes the member to the given type.
    If the member is an Member.Type.ACTIVE member then demoting it will impact the Raft quorum size.
    
    Parameters:
    
    type - The type to which to demote the member.
    
    Returns:
    
    A completable future to be completed once the member has been demoted.
  - remove
```
CompletableFuture<Void> remove()
```
    Removes the member from the configuration.
    If the member is a part of the current Raft quorum (is an Member.Type.ACTIVE member) then the quorum will be impacted by removing the member.
    
    Returns:
    
    A completable future to be completed once the member has been removed from the configuration.

Interface Member

Nested Class Summary

Method Summary

Method Detail

id

address

clientAddress

serverAddress

type

onTypeChange

status

updated

onStatusChange

promote

promote

demote

demote

remove