LogAppender (Apache Ratis Server API 3.1.3 API)

```
public interface LogAppender
```
A LogAppender is for the leader to send appendEntries to a particular follower.

字段概要

字段
限定符和类型字段和说明

static Class<? extends LogAppender> DEFAULT_CLASS

static org.slf4j.Logger LOG

字段
限定符和类型	字段和说明
`static Class<? extends LogAppender>`	`DEFAULT_CLASS`
`static org.slf4j.Logger`	`LOG`

方法概要

所有方法静态方法实例方法抽象方法默认方法已过时的方法
限定符和类型	方法和说明
`long`	`getCallId()`
`Comparator<Long>`	`getCallIdComparator()`
`AwaitForSignal`	`getEventAwaitForSignal()` Get the `AwaitForSignal` for events, which can be: (1) new log entries available, (2) log indices changed, or (3) a snapshot installation completed.
`FollowerInfo`	`getFollower()`
`default RaftPeerId`	`getFollowerId()` The same as getFollower().getPeer().getId().
`default long`	`getHeartbeatWaitTimeMs()`
`LeaderState`	`getLeaderState()`
`default RaftLog`	`getRaftLog()` The same as getServer().getRaftLog().
`RaftServer.Division`	`getServer()`
`default RaftServerRpc`	`getServerRpc()` The same as getServer().getRaftServer().getServerRpc().
`default boolean`	`hasAppendEntries()` Does it have outstanding appendEntries?
`boolean`	`isRunning()` Is this `LogAppender` running?
`org.apache.ratis.proto.RaftProtos.AppendEntriesRequestProto`	`newAppendEntriesRequest(long callId, boolean heartbeat)` Create a `RaftProtos.AppendEntriesRequestProto` object using the `FollowerInfo` of this `LogAppender`.
`org.apache.ratis.proto.RaftProtos.InstallSnapshotRequestProto`	`newInstallSnapshotNotificationRequest(TermIndex firstAvailableLogTermIndex)`
`Iterable<org.apache.ratis.proto.RaftProtos.InstallSnapshotRequestProto>`	`newInstallSnapshotRequests(String requestId, SnapshotInfo snapshot)`
`static LogAppender`	`newLogAppenderDefault(RaftServer.Division server, LeaderState leaderState, FollowerInfo f)` Create the default `LogAppender`.
`default void`	`notifyLogAppender()` The same as getEventAwaitForSignal().signal().
`default boolean`	`onFollowerTerm(long followerTerm)` Handle the event that the follower has replied a term.
`void`	`run()` Define how this `LogAppender` should run.
`default SnapshotInfo`	`shouldInstallSnapshot()` Should this `LogAppender` send a snapshot to the follower?
`default boolean`	`shouldSendAppendEntries()` Should the leader send appendEntries RPC to the follower?
`void`	`start()` Start this `LogAppender`.
`default void`	`stop()` 已过时。 override `stopAsync()` instead.
`default CompletableFuture<?>`	`stopAsync()` Stop this `LogAppender` asynchronously.
`void`	`triggerHeartbeat()` Trigger to send a heartbeat AppendEntries.

- 字段详细资料
  - LOG
```
static final org.slf4j.Logger LOG
```
  - DEFAULT_CLASS
```
static final Class<? extends LogAppender> DEFAULT_CLASS
```
- 方法详细资料
  - newLogAppenderDefault
```
static LogAppender newLogAppenderDefault(RaftServer.Division server,
                                         LeaderState leaderState,
                                         FollowerInfo f)
```
    Create the default LogAppender.
  - getServer
```
RaftServer.Division getServer()
```
    返回:
    
    the server.
  - getServerRpc
```
default RaftServerRpc getServerRpc()
```
    The same as getServer().getRaftServer().getServerRpc().
  - getRaftLog
```
default RaftLog getRaftLog()
```
    The same as getServer().getRaftLog().
  - start
```
void start()
```
    Start this LogAppender.
  - isRunning
```
boolean isRunning()
```
    Is this LogAppender running?
  - stop
```
@Deprecated
default void stop()
```
    已过时。 override stopAsync() instead.
    
    Stop this LogAppender asynchronously.
  - stopAsync
```
default CompletableFuture<?> stopAsync()
```
    Stop this LogAppender asynchronously.
    
    返回:
    
    a future of the final state.
  - getLeaderState
```
LeaderState getLeaderState()
```
    返回:
    
    the leader state.
  - getFollower
```
FollowerInfo getFollower()
```
    返回:
    
    the follower information for this LogAppender.
  - getFollowerId
```
default RaftPeerId getFollowerId()
```
    The same as getFollower().getPeer().getId().
  - getCallId
```
long getCallId()
```
    返回:
    
    the call id for the next RaftProtos.AppendEntriesRequestProto.
  - getCallIdComparator
```
Comparator<Long> getCallIdComparator()
```
    返回:
    
    the a Comparator for comparing call ids.
  - newAppendEntriesRequest
```
org.apache.ratis.proto.RaftProtos.AppendEntriesRequestProto newAppendEntriesRequest(long callId,
                                                                                    boolean heartbeat)
                                                                             throws RaftLogIOException
```
    Create a RaftProtos.AppendEntriesRequestProto object using the FollowerInfo of this LogAppender. The RaftProtos.AppendEntriesRequestProto object may contain zero or more log entries. When there is zero log entries, the RaftProtos.AppendEntriesRequestProto object is a heartbeat.
    
    参数:
    
    callId - The call id of the returned request.
    
    heartbeat - the returned request must be a heartbeat.
    
    返回:
    
    a new RaftProtos.AppendEntriesRequestProto object.
    
    抛出:
    
    RaftLogIOException
  - newInstallSnapshotNotificationRequest
```
org.apache.ratis.proto.RaftProtos.InstallSnapshotRequestProto newInstallSnapshotNotificationRequest(TermIndex firstAvailableLogTermIndex)
```
    返回:
    
    a new RaftProtos.InstallSnapshotRequestProto object.
  - newInstallSnapshotRequests
```
Iterable<org.apache.ratis.proto.RaftProtos.InstallSnapshotRequestProto> newInstallSnapshotRequests(String requestId,
                                                                                                   SnapshotInfo snapshot)
```
    返回:
    
    an Iterable of RaftProtos.InstallSnapshotRequestProto for sending the given snapshot.
  - shouldInstallSnapshot
```
default SnapshotInfo shouldInstallSnapshot()
```
    Should this LogAppender send a snapshot to the follower?
    
    返回:
    
    the snapshot if it should install a snapshot; otherwise, return null.
  - run
```
void run()
  throws InterruptedException,
         IOException
```
    Define how this LogAppender should run.
    
    抛出:
    
    InterruptedException
    
    IOException
  - getEventAwaitForSignal
```
AwaitForSignal getEventAwaitForSignal()
```
    Get the AwaitForSignal for events, which can be: (1) new log entries available, (2) log indices changed, or (3) a snapshot installation completed.
  - notifyLogAppender
```
default void notifyLogAppender()
```
    The same as getEventAwaitForSignal().signal().
  - shouldSendAppendEntries
```
default boolean shouldSendAppendEntries()
```
    Should the leader send appendEntries RPC to the follower?
  - hasAppendEntries
```
default boolean hasAppendEntries()
```
    Does it have outstanding appendEntries?
  - triggerHeartbeat
```
void triggerHeartbeat()
```
    Trigger to send a heartbeat AppendEntries.
  - getHeartbeatWaitTimeMs
```
default long getHeartbeatWaitTimeMs()
```
    返回:
    
    the wait time in milliseconds to send the next heartbeat.
  - onFollowerTerm
```
default boolean onFollowerTerm(long followerTerm)
```
    Handle the event that the follower has replied a term.

接口 LogAppender

字段概要

方法概要

字段详细资料

LOG

DEFAULT_CLASS

方法详细资料

newLogAppenderDefault

getServer

getServerRpc

getRaftLog

start

isRunning

stop

stopAsync

getLeaderState

getFollower

getFollowerId

getCallId

getCallIdComparator

newAppendEntriesRequest

newInstallSnapshotNotificationRequest

newInstallSnapshotRequests

shouldInstallSnapshot

run

getEventAwaitForSignal

notifyLogAppender

shouldSendAppendEntries

hasAppendEntries

triggerHeartbeat

getHeartbeatWaitTimeMs

onFollowerTerm