Interface StreamReplicator.Reader

All Superinterfaces:

AutoCloseable, Closeable, Replicator.Accessor, Replicator.Reader

Enclosing interface:

StreamReplicator

public static interface StreamReplicator.Reader
extends Replicator.Reader

Interface called by any group member for reading committed messages. Readers don't track which messages are applied — applications are responsible for tracking the highest applied position. When an application restarts, it must open the reader at an appropriate position.

See Also:

• newReader

Method Summary

Modifier and Type	Method	Description
default int	read(byte[] buf)	Blocks until log messages are available, never reading past a commit position or term.
int	read(byte[] buf, int offset, int length)	Blocks until log messages are available, never reading past a commit position or term.
default void	readFully(byte[] buf, int offset, int length)	Blocks until the buffer is fully read with messages, never reading past a commit position or term.
int	tryRead(byte[] buf, int offset, int length)	Reads whatever log data is available, never higher than a commit position, never higher than a term, and never blocking.

Methods inherited from interface Replicator.Accessor

addCommitListener, close, commitPosition, position, term, termEndPosition, termStartPosition, uponCommit, waitForCommit, waitForEndCommit

Modifier and Type	Method	Description
void	addCommitListener(LongConsumer listener)	Install a callback which receives a stream of commit position updates.
void	close()
long	commitPosition()	Returns the current term commit position, which might be lower than the start position.
long	position()	Returns the next log position which will be accessed.
long	term()	Returns the fixed term being accessed.
long	termEndPosition()	Returns the current term end position, which is Long.MAX_VALUE if unbounded.
long	termStartPosition()	Returns the position at the start of the term.
void	uponCommit(long position, LongConsumer task)	Invokes the given task when the commit position reaches the requested position.
long	waitForCommit(long position, long nanosTimeout)	Blocks until the commit position reaches the given position.
default long	waitForEndCommit(long nanosTimeout)	Blocks until the commit position reaches the end of the term.

Method Details

read

default int read(byte[] buf)
          throws IOException

Blocks until log messages are available, never reading past a commit position or term.

Returns:

amount of bytes read, or EOF (-1) if the term end has been reached

Throws:

InvalidReadException - if log was deleted (position is too low)

IOException

read

int read(byte[] buf,
 int offset,
 int length)
  throws IOException

Blocks until log messages are available, never reading past a commit position or term.

Returns:

amount of bytes read, or EOF (-1) if the term end has been reached

Throws:

InvalidReadException - if log was deleted (position is too low)

IOException

readFully

default void readFully(byte[] buf,
 int offset,
 int length)
                throws IOException

Blocks until the buffer is fully read with messages, never reading past a commit position or term.

Throws:

InvalidReadException - if log was deleted (position is too low)

EOFException - if the term end has been reached too soon

IOException

tryRead

int tryRead(byte[] buf,
 int offset,
 int length)
     throws IOException

Reads whatever log data is available, never higher than a commit position, never higher than a term, and never blocking.

Returns:

amount of bytes read, or EOF (-1) if the term end has been reached

Throws:

InvalidReadException - if log data was deleted (position is too low)

IOException