org.apache.flink.core.fs

Class RefCountedBufferingFileStream

java.lang.Object

java.io.OutputStream

org.apache.flink.core.fs.FSDataOutputStream

org.apache.flink.core.fs.RefCountedFSOutputStream

org.apache.flink.core.fs.RefCountedBufferingFileStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable, RefCounted

@Internal
public class RefCountedBufferingFileStream
extends RefCountedFSOutputStream

A RefCountedFileWithStream that also uses an in-memory buffer for buffering small writes. This is done to avoid frequent 'flushes' of the file stream to disk.

Field Summary

Fields

Modifier and Type	Field and Description
static int	BUFFER_SIZE

Constructor Summary

Constructors

Constructor and Description
RefCountedBufferingFileStream(RefCountedFileWithStream file, int bufferSize)

Method Summary

Modifier and Type	Method and Description
void	close() Closes the output stream.
void	flush() Flushes the stream, writing any data currently buffered in stream implementation to the proper output stream.
File	getInputFile() Gets the underlying File that allows to read the contents of the file.
long	getPos() Gets the position of the stream (non-negative), defined as the number of bytes from the beginning of the file to the current writing position.
int	getReferenceCounter()
boolean	isClosed() Checks if the file is closed for writes.
static RefCountedBufferingFileStream	openNew(FunctionWithException<File,RefCountedFileWithStream,IOException> tmpFileProvider)
boolean	release() Decreases the reference counter.
static RefCountedBufferingFileStream	restore(FunctionWithException<File,RefCountedFileWithStream,IOException> tmpFileProvider, File initialTmpFile)
void	retain() Increases the reference counter.
void	sync() Flushes the data all the way to the persistent non-volatile storage (for example disks).
String	toString()
void	write(byte[] b, int off, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

write

Methods inherited from class java.lang.Object

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

Field Detail

BUFFER_SIZE

public static final int BUFFER_SIZE

See Also:

Constant Field Values

Constructor Detail

RefCountedBufferingFileStream

@VisibleForTesting
public RefCountedBufferingFileStream(RefCountedFileWithStream file,
                                                        int bufferSize)

Method Detail

getInputFile

public File getInputFile()

Description copied from class: RefCountedFSOutputStream

Gets the underlying File that allows to read the contents of the file.

Specified by:

getInputFile in class RefCountedFSOutputStream

Returns:

A handle to the File object.

getPos

public long getPos()

Description copied from class: FSDataOutputStream

Gets the position of the stream (non-negative), defined as the number of bytes from the beginning of the file to the current writing position. The position corresponds to the zero-based index of the next byte that will be written.

This method must report accurately report the current position of the stream. Various components of the high-availability and recovery logic rely on the accurate

Specified by:

getPos in class FSDataOutputStream

Returns:

The current position in the stream, defined as the number of bytes from the beginning of the file to the current writing position.

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b,
                  int off,
                  int len)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Description copied from class: FSDataOutputStream

Flushes the stream, writing any data currently buffered in stream implementation to the proper output stream. After this method has been called, the stream implementation must not hold onto any buffered data any more.

A completed flush does not mean that the data is necessarily persistent. Data persistence can is only assumed after calls to FSDataOutputStream.close() or FSDataOutputStream.sync().

Implementation note: This overrides the method defined in OutputStream as abstract to force implementations of the FSDataOutputStream to implement this method directly.

Specified by:

flush in interface Flushable

Specified by:

flush in class FSDataOutputStream

Throws:

IOException - Thrown if an I/O error occurs while flushing the stream.

sync

public void sync()
          throws IOException

Description copied from class: FSDataOutputStream

Flushes the data all the way to the persistent non-volatile storage (for example disks). The method behaves similar to the fsync function, forcing all data to be persistent on the devices.

Specified by:

sync in class FSDataOutputStream

Throws:

IOException - Thrown if an I/O error occurs

isClosed

public boolean isClosed()
                 throws IOException

Description copied from class: RefCountedFSOutputStream

Checks if the file is closed for writes.

Specified by:

isClosed in class RefCountedFSOutputStream

Returns:

true if the file is closed, false otherwise.

Throws:

IOException

close

public void close()

Description copied from class: FSDataOutputStream

Closes the output stream. After this method returns, the implementation must guarantee that all data written to the stream is persistent/visible, as defined in the class-level docs.

The above implies that the method must block until persistence can be guaranteed. For example for distributed replicated file systems, the method must block until the replication quorum has been reached. If the calling thread is interrupted in the process, it must fail with an IOException to indicate that persistence cannot be guaranteed.

If this method throws an exception, the data in the stream cannot be assumed to be persistent.

Implementation note: This overrides the method defined in OutputStream as abstract to force implementations of the FSDataOutputStream to implement this method directly.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class FSDataOutputStream

retain

public void retain()

Description copied from interface: RefCounted

Increases the reference counter.

release

public boolean release()

Description copied from interface: RefCounted

Decreases the reference counter.

Returns:

true if the reference counter reached 0, false otherwise.

toString

public String toString()

Overrides:

toString in class Object

getReferenceCounter

@VisibleForTesting
public int getReferenceCounter()

openNew

public static RefCountedBufferingFileStream openNew(FunctionWithException<File,RefCountedFileWithStream,IOException> tmpFileProvider)
                                             throws IOException

Throws:

IOException

restore

public static RefCountedBufferingFileStream restore(FunctionWithException<File,RefCountedFileWithStream,IOException> tmpFileProvider,
                                                    File initialTmpFile)
                                             throws IOException

Throws:

IOException