ReplicatedLog (controller 0.8.4-SNAPSHOT API)

All Known Implementing Classes:

AbstractReplicatedLogImpl
```
public interface ReplicatedLog
```
Represents the ReplicatedLog that needs to be kept in sync by the RaftActor.

Field Summary

Fields
Modifier and Type Field and Description

static long NO_MAX_SIZE

Fields
Modifier and Type	Field and Description
`static long`	`NO_MAX_SIZE`

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`boolean`	`append(ReplicatedLogEntry replicatedLogEntry)` Appends an entry to the log.
`boolean`	`appendAndPersist(ReplicatedLogEntry replicatedLogEntry, akka.japi.Procedure<ReplicatedLogEntry> callback, boolean doAsync)` Appends an entry to the in-memory log and persists it as well.
`void`	`captureSnapshotIfReady(ReplicatedLogEntry replicatedLogEntry)` Determines if a snapshot needs to be captured based on the count/memory consumed and initiates the capture.
`void`	`clear(int startIndex, int endIndex)` Clears the journal entries with startIndex (inclusive) and endIndex (exclusive).
`int`	`dataSize()` Returns the size of the data in the log (in bytes).
`ReplicatedLogEntry`	`get(long index)` Return the replicated log entry at the specified index.
`List<ReplicatedLogEntry>`	`getFrom(long index)` Returns a list of log entries starting from the given index to the end of the log.
`List<ReplicatedLogEntry>`	`getFrom(long index, int maxEntries, long maxDataSize)` Returns a list of log entries starting from the given index up to the given maximum of entries or the given maximum accumulated size, whichever comes first.
`long`	`getSnapshotIndex()` Returns the index of the snapshot.
`long`	`getSnapshotTerm()` Returns the term of the snapshot.
`void`	`increaseJournalLogCapacity(int amount)` Optimization method to increase the capacity of the journal log prior to appending entries.
`boolean`	`isInSnapshot(long index)` Checks if the entry is present in a snapshot.
`boolean`	`isPresent(long index)` Checks if the entry at the specified index is present or not.
`ReplicatedLogEntry`	`last()` Return the last replicated log entry in the log or null of not found.
`long`	`lastIndex()` Return the index of the last entry in the log or -1 if the log is empty.
`long`	`lastTerm()` Return the term of the last entry in the log or -1 if the log is empty.
`long`	`removeFrom(long index)` Removes entries from the in-memory log starting at the given index.
`boolean`	`removeFromAndPersist(long index)` Removes entries from the in-memory log and the persisted log starting at the given index.
`void`	`setSnapshotIndex(long snapshotIndex)` Sets the snapshot index in the replicated log.
`void`	`setSnapshotTerm(long snapshotTerm)` Sets snapshot term.
`boolean`	`shouldCaptureSnapshot(long logIndex)` Determines if a snapshot should be captured based on the count/memory consumed.
`long`	`size()` Returns the number of entries in the journal.
`void`	`snapshotCommit()` Sets the Replicated log to state after snapshot success.
`void`	`snapshotPreCommit(long snapshotCapturedIndex, long snapshotCapturedTerm)` Handles all the bookkeeping in order to perform a rollback in the event of SaveSnapshotFailure.
`void`	`snapshotRollback()` Restores the replicated log to a state in the event of a save snapshot failure.

- Field Detail
  - NO_MAX_SIZE
```
static final long NO_MAX_SIZE
```
    See Also:
    
    Constant Field Values
- Method Detail
  - get
```
@Nullable
ReplicatedLogEntry get(long index)
```
    Return the replicated log entry at the specified index.
    
    Parameters:
    
    index - the index of the log entry
    
    Returns:
    
    the ReplicatedLogEntry if found, otherwise null if the adjusted index less than 0 or greater than the size of the in-memory journal
  - last
```
@Nullable
ReplicatedLogEntry last()
```
    Return the last replicated log entry in the log or null of not found.
    
    Returns:
    
    the last replicated log entry in the log or null of not found.
  - lastIndex
```
long lastIndex()
```
    Return the index of the last entry in the log or -1 if the log is empty.
    
    Returns:
    
    the index of the last entry in the log or -1 if the log is empty.
  - lastTerm
```
long lastTerm()
```
    Return the term of the last entry in the log or -1 if the log is empty.
    
    Returns:
    
    the term of the last entry in the log or -1 if the log is empty.
  - removeFrom
```
long removeFrom(long index)
```
    Removes entries from the in-memory log starting at the given index.
    
    Parameters:
    
    index - the index of the first log entry to remove
    
    Returns:
    
    the adjusted index of the first log entry removed or -1 if the log entry is not found.
  - removeFromAndPersist
```
boolean removeFromAndPersist(long index)
```
    Removes entries from the in-memory log and the persisted log starting at the given index.
    The persisted information would then be used during recovery to properly reconstruct the state of the in-memory replicated log
    
    Parameters:
    
    index - the index of the first log entry to remove
    
    Returns:
    
    true if entries were removed, false otherwise
  - append
```
boolean append(ReplicatedLogEntry replicatedLogEntry)
```
    Appends an entry to the log.
    
    Parameters:
    
    replicatedLogEntry - the entry to append
    
    Returns:
    
    true if the entry was successfully appended, false otherwise. An entry can fail to append if the index is already included in the log.
  - increaseJournalLogCapacity
```
void increaseJournalLogCapacity(int amount)
```
    Optimization method to increase the capacity of the journal log prior to appending entries.
    
    Parameters:
    
    amount - the amount to increase by
  - appendAndPersist
```
boolean appendAndPersist(@Nonnull
                         ReplicatedLogEntry replicatedLogEntry,
                         @Nullable
                         akka.japi.Procedure<ReplicatedLogEntry> callback,
                         boolean doAsync)
```
    Appends an entry to the in-memory log and persists it as well.
    
    Parameters:
    
    replicatedLogEntry - the entry to append
    
    callback - the Procedure to be notified when persistence is complete (optional).
    
    doAsync - if true, the persistent actor can receive subsequent messages to process in between the persist call and the execution of the associated callback. If false, subsequent messages are stashed and get delivered after persistence is complete and the associated callback is executed. In either case the callback is guaranteed to execute in the context of the actor associated with this log.
    
    Returns:
    
    true if the entry was successfully appended, false otherwise.
  - getFrom
```
@Nonnull
List<ReplicatedLogEntry> getFrom(long index)
```
    Returns a list of log entries starting from the given index to the end of the log.
    
    Parameters:
    
    index - the index of the first log entry to get.
    
    Returns:
    
    the List of entries
  - getFrom
```
@Nonnull
List<ReplicatedLogEntry> getFrom(long index,
                                          int maxEntries,
                                          long maxDataSize)
```
    Returns a list of log entries starting from the given index up to the given maximum of entries or the given maximum accumulated size, whichever comes first.
    
    Parameters:
    
    index - the index of the first log entry to get
    
    maxEntries - the maximum number of entries to get
    
    maxDataSize - the maximum accumulated size of the log entries to get
    
    Returns:
    
    the List of entries meeting the criteria.
  - size
```
long size()
```
    Returns the number of entries in the journal.
    
    Returns:
    
    the number of entries
  - isPresent
```
boolean isPresent(long index)
```
    Checks if the entry at the specified index is present or not.
    
    Parameters:
    
    index - the index of the log entry
    
    Returns:
    
    true if the entry is present in the in-memory journal
  - isInSnapshot
```
boolean isInSnapshot(long index)
```
    Checks if the entry is present in a snapshot.
    
    Parameters:
    
    index - the index of the log entry
    
    Returns:
    
    true if the entry is in the snapshot. false if the entry is not in the snapshot even if the entry may be present in the replicated log
  - getSnapshotIndex
```
long getSnapshotIndex()
```
    Returns the index of the snapshot.
    
    Returns:
    
    the index from which the snapshot was created. -1 otherwise.
  - getSnapshotTerm
```
long getSnapshotTerm()
```
    Returns the term of the snapshot.
    
    Returns:
    
    the term of the index from which the snapshot was created. -1 otherwise
  - setSnapshotIndex
```
void setSnapshotIndex(long snapshotIndex)
```
    Sets the snapshot index in the replicated log.
    
    Parameters:
    
    snapshotIndex - the index to set
  - setSnapshotTerm
```
void setSnapshotTerm(long snapshotTerm)
```
    Sets snapshot term.
    
    Parameters:
    
    snapshotTerm - the term to set
  - clear
```
void clear(int startIndex,
           int endIndex)
```
    Clears the journal entries with startIndex (inclusive) and endIndex (exclusive).
    
    Parameters:
    
    startIndex - the start index (inclusive)
    
    endIndex - the end index (exclusive)
  - snapshotPreCommit
```
void snapshotPreCommit(long snapshotCapturedIndex,
                       long snapshotCapturedTerm)
```
    Handles all the bookkeeping in order to perform a rollback in the event of SaveSnapshotFailure.
    
    Parameters:
    
    snapshotCapturedIndex - the new snapshot index
    
    snapshotCapturedTerm - the new snapshot term
  - snapshotCommit
```
void snapshotCommit()
```
    Sets the Replicated log to state after snapshot success.
  - snapshotRollback
```
void snapshotRollback()
```
    Restores the replicated log to a state in the event of a save snapshot failure.
  - dataSize
```
int dataSize()
```
    Returns the size of the data in the log (in bytes).
    
    Returns:
    
    the size of the data in the log (in bytes)
  - captureSnapshotIfReady
```
void captureSnapshotIfReady(ReplicatedLogEntry replicatedLogEntry)
```
    Determines if a snapshot needs to be captured based on the count/memory consumed and initiates the capture.
    
    Parameters:
    
    replicatedLogEntry - the last log entry.
  - shouldCaptureSnapshot
```
boolean shouldCaptureSnapshot(long logIndex)
```
    Determines if a snapshot should be captured based on the count/memory consumed.
    
    Parameters:
    
    logIndex - the log index to use to determine if the log count has exceeded the threshold
    
    Returns:
    
    true if a snapshot should be captured, false otherwise

Interface ReplicatedLog

Field Summary

Method Summary

Field Detail

NO_MAX_SIZE

Method Detail

get

last

lastIndex

lastTerm

removeFrom

removeFromAndPersist

append

increaseJournalLogCapacity

appendAndPersist

getFrom

getFrom

size

isPresent

isInSnapshot

getSnapshotIndex

getSnapshotTerm

setSnapshotIndex

setSnapshotTerm

clear

snapshotPreCommit

snapshotCommit

snapshotRollback

dataSize

captureSnapshotIfReady

shouldCaptureSnapshot