Package org.apache.flink.runtime.state.filesystem

Class FsCheckpointMetadataOutputStream

java.lang.Object

java.io.OutputStream

org.apache.flink.core.fs.FSDataOutputStream

org.apache.flink.runtime.state.CheckpointMetadataOutputStream

org.apache.flink.runtime.state.filesystem.FsCheckpointMetadataOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public final class FsCheckpointMetadataOutputStream
extends CheckpointMetadataOutputStream

A CheckpointMetadataOutputStream that writes a specified file and directory, and returns a FsCompletedCheckpointStorageLocation upon closing.

Constructor Summary

Constructors

Constructor	Description
FsCheckpointMetadataOutputStream(FileSystem fileSystem, Path metadataFilePath, Path exclusiveCheckpointDir)

Method Summary

Modifier and Type	Method	Description
void	close()	This method should close the stream, if has not been closed before.
FsCompletedCheckpointStorageLocation	closeAndFinalizeCheckpoint()	Closes the stream after all metadata was written and finalizes the checkpoint location.
void	flush()	Flushes the stream, writing any data currently buffered in stream implementation to the proper output stream.
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.
boolean	isClosed()
void	sync()	Flushes the data all the way to the persistent non-volatile storage (for example disks).
void	write(byte[] b, int off, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

nullOutputStream, write

Methods inherited from class java.lang.Object

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

Constructor Detail

FsCheckpointMetadataOutputStream

public FsCheckpointMetadataOutputStream(FileSystem fileSystem,
                                        Path metadataFilePath,
                                        Path exclusiveCheckpointDir)
                                 throws IOException

Throws:

IOException

Method Detail

write

public final void write(int b)
                 throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

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

Overrides:

write in class OutputStream

Throws:

IOException

getPos

public long getPos()
            throws IOException

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.

Throws:

IOException - Thrown if an I/O error occurs while obtaining the position from the stream implementation.

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()

close

public void close()

Description copied from class: CheckpointMetadataOutputStream

This method should close the stream, if has not been closed before. If this method actually closes the stream, it should delete/release the resource behind the stream, such as the file that the stream writes to.

The above implies that this method is intended to be the "unsuccessful close", such as when cancelling the stream writing, or when an exception occurs. Closing the stream for the successful case must go through CheckpointMetadataOutputStream.closeAndFinalizeCheckpoint().

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class CheckpointMetadataOutputStream

closeAndFinalizeCheckpoint

public FsCompletedCheckpointStorageLocation closeAndFinalizeCheckpoint()
                                                                throws IOException

Description copied from class: CheckpointMetadataOutputStream

Closes the stream after all metadata was written and finalizes the checkpoint location.

Specified by:

closeAndFinalizeCheckpoint in class CheckpointMetadataOutputStream

Returns:

An object representing a finalized checkpoint storage location.

Throws:

IOException - Thrown, if the stream cannot be closed or the finalization fails.