AppendRequest (JSimpleDB Raft Key/Value Store 2.4.1 API)

java.lang.Object
- org.jsimpledb.kv.raft.msg.Message
- - org.jsimpledb.kv.raft.msg.AppendRequest

```
public class AppendRequest
extends Message
```
Sent from leaders to followers to probe the follower's log state and/or append an entry to their log.
Instances also provide the leader's lease timeout value (if any), which is used to commit read-only transactions, as well as a leader timestamp which should be reflected back in the corresponding AppendResponse.

Constructor Summary

Constructors
Constructor and Description
`AppendRequest(int clusterId, String senderId, String recipientId, long term, Timestamp leaderTimestamp, Timestamp leaderLeaseTimeout, long leaderCommit, long prevLogTerm, long prevLogIndex)` Constructor for a "probe" that does not contain a log entry.
`AppendRequest(int clusterId, String senderId, String recipientId, long term, Timestamp leaderTimestamp, Timestamp leaderLeaseTimeout, long leaderCommit, long prevLogTerm, long prevLogIndex, long logEntryTerm, ByteBuffer mutationData)` Constructor for a request that contains an actual log entry.

Method Summary

Methods
Modifier and Type	Method and Description
`protected int`	`calculateSize()` Calculate an upper bound on the number of bytes required by `writeTo()`.
`long`	`getLeaderCommit()` Get leader's commit index.
`Timestamp`	`getLeaderLeaseTimeout()`
`Timestamp`	`getLeaderTimestamp()`
`long`	`getLogEntryTerm()`
`ByteBuffer`	`getMutationData()` Get the serialized data for the log entry, if any.
`long`	`getPrevLogIndex()`
`long`	`getPrevLogTerm()`
`boolean`	`isLeaderMessage()` Determine whether this message is only sent by leaders.
`boolean`	`isProbe()`
`String`	`toString()`
`void`	`visit(MessageSwitch handler)` Apply the visitor pattern based on this instance's type.
`void`	`writeTo(ByteBuffer dest)` Serialize this instance into the given buffer.

Methods inherited from class org.jsimpledb.kv.raft.msg.Message
calculateSize, calculateSize, calculateSize, decode, encode, getBoolean, getByteBuffer, getClusterId, getReads, getRecipientId, getSenderId, getString, getTerm, getTimestamp, getWrites, putBoolean, putByteBuffer, putReads, putString, putTimestamp, putWrites

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - AppendRequest
```
public AppendRequest(int clusterId,
             String senderId,
             String recipientId,
             long term,
             Timestamp leaderTimestamp,
             Timestamp leaderLeaseTimeout,
             long leaderCommit,
             long prevLogTerm,
             long prevLogIndex)
```
    Constructor for a "probe" that does not contain a log entry.
    Note that leaderCommit is limited to prevLogIndex by this constructor, because we can't guarantee that omitted the log entry at prevLogIndex + 1 matches whatever the follower has in its log.
    
    Parameters:
    clusterId - cluster ID
    senderId - identity of sender
    recipientId - identity of recipient
    term - sender's current term
    leaderTimestamp - leader's timestamp for this request
    leaderLeaseTimeout - earliest leader timestamp at which leader could be deposed (or null)
    leaderCommit - current commit index for sender
    prevLogTerm - term of the log entry just prior to this one
    prevLogIndex - index of the log entry just prior to this one
  - AppendRequest
```
public AppendRequest(int clusterId,
             String senderId,
             String recipientId,
             long term,
             Timestamp leaderTimestamp,
             Timestamp leaderLeaseTimeout,
             long leaderCommit,
             long prevLogTerm,
             long prevLogIndex,
             long logEntryTerm,
             ByteBuffer mutationData)
```
    Constructor for a request that contains an actual log entry.
    
    Parameters:
    clusterId - cluster ID
    senderId - identity of sender
    recipientId - identity of recipient
    term - sender's current term
    leaderTimestamp - leader's timestamp for this request
    leaderLeaseTimeout - earliest leader timestamp at which leader could be deposed (or null)
    leaderCommit - current commit index for sender
    prevLogTerm - term of the log entry just prior to this one
    prevLogIndex - index of the log entry just prior to this one
    logEntryTerm - term of this log entry
    mutationData - log entry serialized mutations, or null if follower should have the data already
- Method Detail
  - getLeaderTimestamp
```
public Timestamp getLeaderTimestamp()
```
  - getLeaderLeaseTimeout
```
public Timestamp getLeaderLeaseTimeout()
```
  - getLeaderCommit
```
public long getLeaderCommit()
```
    Get leader's commit index.
    For probe requests, this value is limited to the value returned by getPrevLogIndex().
  - getPrevLogTerm
```
public long getPrevLogTerm()
```
  - getPrevLogIndex
```
public long getPrevLogIndex()
```
  - isProbe
```
public boolean isProbe()
```
  - getLogEntryTerm
```
public long getLogEntryTerm()
```
  - getMutationData
```
public ByteBuffer getMutationData()
```
    Get the serialized data for the log entry, if any. Returns null if this is a probe or follower is expected to already have the data from a transaction.
    This method may only be invoked once.
    
    Returns:
    log entry serialized mutations, or null if this message does not contain data
    
    Throws:
    
    IllegalStateException - if this method has already been invoked
  - isLeaderMessage
```
public boolean isLeaderMessage()
```
    Description copied from class: Message
    
    Determine whether this message is only sent by leaders.
    
    Overrides:
    
    isLeaderMessage in class Message
    
    Returns:
    true if receipt of this message implies sender is a leader
  - visit
```
public void visit(MessageSwitch handler)
```
    Description copied from class: Message
    
    Apply the visitor pattern based on this instance's type.
    
    Specified by:
    
    visit in class Message
    
    Parameters:
    handler - target for visit
  - writeTo
```
public void writeTo(ByteBuffer dest)
```
    Description copied from class: Message
    
    Serialize this instance into the given buffer.
    
    Overrides:
    
    writeTo in class Message
    
    Parameters:
    dest - destination for encoded data
  - calculateSize
```
protected int calculateSize()
```
    Description copied from class: Message
    
    Calculate an upper bound on the number of bytes required by writeTo().
    
    Overrides:
    
    calculateSize in class Message
    
    Returns:
    an upper bound on the number of encoded bytes
  - toString
```
public String toString()
```
    Specified by:
    
    toString in class Message

Class AppendRequest

Constructor Summary

Method Summary

Methods inherited from class org.jsimpledb.kv.raft.msg.Message

Methods inherited from class java.lang.Object

Constructor Detail

AppendRequest

AppendRequest

Method Detail

getLeaderTimestamp

getLeaderLeaseTimeout

getLeaderCommit

getPrevLogTerm

getPrevLogIndex

isProbe

getLogEntryTerm

getMutationData

isLeaderMessage

visit

writeTo

calculateSize

toString