Package org.apache.bookkeeper.bookie

Class BufferedChannel

java.lang.Object

org.apache.bookkeeper.bookie.BufferedChannelBase

org.apache.bookkeeper.bookie.BufferedReadChannel

org.apache.bookkeeper.bookie.BufferedChannel

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

DefaultEntryLogger.BufferedLogChannel, SlowBufferedChannel

public class BufferedChannel
extends BufferedReadChannel
implements java.io.Closeable

Provides a buffering layer in front of a FileChannel.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.bookkeeper.bookie.BufferedChannelBase

BufferedChannelBase.BufferedChannelClosedException

Field Summary

Fields

Modifier and Type	Field	Description
protected long	position	The absolute position of the next write operation.
protected java.util.concurrent.atomic.AtomicLong	unpersistedBytes
protected long	unpersistedBytesBound
protected io.netty.buffer.ByteBuf	writeBuffer	The buffer used to write operations.
protected java.util.concurrent.atomic.AtomicLong	writeBufferStartPosition	The position of the file channel's write pointer.
protected int	writeCapacity	The capacity of the write buffer.

Fields inherited from class org.apache.bookkeeper.bookie.BufferedReadChannel

cacheHitCount, invocationCount, readBuffer, readBufferStartPosition, readCapacity, sealed

Fields inherited from class org.apache.bookkeeper.bookie.BufferedChannelBase

fileChannel

Constructor Summary

Constructors

Constructor	Description
BufferedChannel(io.netty.buffer.ByteBufAllocator allocator, java.nio.channels.FileChannel fc, int capacity)
BufferedChannel(io.netty.buffer.ByteBufAllocator allocator, java.nio.channels.FileChannel fc, int writeCapacity, int readCapacity, long unpersistedBytesBound)
BufferedChannel(io.netty.buffer.ByteBufAllocator allocator, java.nio.channels.FileChannel fc, int capacity, long unpersistedBytesBound)

Method Summary

Modifier and Type	Method	Description
void	clear()
void	close()
void	flush()	Write any data in the buffer to the file and advance the writeBufferPosition.
void	flushAndForceWrite(boolean forceMetadata)	calls both flush and forceWrite methods.
void	flushAndForceWriteIfRegularFlush(boolean forceMetadata)	calls both flush and forceWrite methods if regular flush is enabled.
long	forceWrite(boolean forceMetadata)	force a sync operation so that data is persisted to the disk.
long	getFileChannelPosition()	Get the position of the file channel's write pointer.
int	getNumOfBytesInWriteBuffer()
(package private) long	getUnpersistedBytes()
long	position()	Get the position where the next write operation will begin writing from.
int	read(io.netty.buffer.ByteBuf dest, long pos, int length)
void	write(io.netty.buffer.ByteBuf src)	Write all the data in src to the FileChannel.

Methods inherited from class org.apache.bookkeeper.bookie.BufferedReadChannel

read, size

Methods inherited from class org.apache.bookkeeper.bookie.BufferedChannelBase

validateAndGetFileChannel

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

writeCapacity

protected final int writeCapacity

The capacity of the write buffer.

writeBufferStartPosition

protected java.util.concurrent.atomic.AtomicLong writeBufferStartPosition

The position of the file channel's write pointer.

writeBuffer

protected final io.netty.buffer.ByteBuf writeBuffer

The buffer used to write operations.

position

protected volatile long position

The absolute position of the next write operation.

unpersistedBytesBound

protected final long unpersistedBytesBound

unpersistedBytes

protected final java.util.concurrent.atomic.AtomicLong unpersistedBytes

Constructor Detail

BufferedChannel

public BufferedChannel(io.netty.buffer.ByteBufAllocator allocator,
                       java.nio.channels.FileChannel fc,
                       int capacity)
                throws java.io.IOException

Throws:

java.io.IOException

BufferedChannel

public BufferedChannel(io.netty.buffer.ByteBufAllocator allocator,
                       java.nio.channels.FileChannel fc,
                       int capacity,
                       long unpersistedBytesBound)
                throws java.io.IOException

Throws:

java.io.IOException

BufferedChannel

public BufferedChannel(io.netty.buffer.ByteBufAllocator allocator,
                       java.nio.channels.FileChannel fc,
                       int writeCapacity,
                       int readCapacity,
                       long unpersistedBytesBound)
                throws java.io.IOException

Throws:

java.io.IOException

Method Detail

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Throws:

java.io.IOException

write

public void write(io.netty.buffer.ByteBuf src)
           throws java.io.IOException

Write all the data in src to the FileChannel. Note that this function can buffer or re-order writes based on the implementation. These writes will be flushed to the disk only when flush() is invoked.

Parameters:

src - The source ByteBuffer which contains the data to be written.

Throws:

java.io.IOException - if a write operation fails.

position

public long position()

Get the position where the next write operation will begin writing from.

Returns:

getFileChannelPosition

public long getFileChannelPosition()

Get the position of the file channel's write pointer.

Returns:

flushAndForceWrite

public void flushAndForceWrite(boolean forceMetadata)
                        throws java.io.IOException

calls both flush and forceWrite methods.

Parameters:

forceMetadata - - If true then this method is required to force changes to both the file's content and metadata to be written to storage; otherwise, it need only force content changes to be written

Throws:

java.io.IOException

flushAndForceWriteIfRegularFlush

public void flushAndForceWriteIfRegularFlush(boolean forceMetadata)
                                      throws java.io.IOException

calls both flush and forceWrite methods if regular flush is enabled.

Parameters:

forceMetadata - - If true then this method is required to force changes to both the file's content and metadata to be written to storage; otherwise, it need only force content changes to be written

Throws:

java.io.IOException

flush

public void flush()
           throws java.io.IOException

Write any data in the buffer to the file and advance the writeBufferPosition. Callers are expected to synchronize appropriately

Throws:

java.io.IOException - if the write fails.

forceWrite

public long forceWrite(boolean forceMetadata)
                throws java.io.IOException

force a sync operation so that data is persisted to the disk.

Parameters:

forceMetadata -

Returns:

Throws:

java.io.IOException

read

public int read(io.netty.buffer.ByteBuf dest,
                long pos,
                int length)
         throws java.io.IOException

Overrides:

read in class BufferedReadChannel

Throws:

java.io.IOException

clear

public void clear()

Overrides:

clear in class BufferedReadChannel

getNumOfBytesInWriteBuffer

public int getNumOfBytesInWriteBuffer()

getUnpersistedBytes

long getUnpersistedBytes()