org.apache.flink.runtime.fs.hdfs

Class HadoopDataOutputStream

java.lang.Object

java.io.OutputStream

org.apache.flink.core.fs.FSDataOutputStream

org.apache.flink.runtime.fs.hdfs.HadoopDataOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class HadoopDataOutputStream
extends FSDataOutputStream

Concrete implementation of the FSDataOutputStream for Hadoop's input streams. This supports all file systems supported by Hadoop, such as HDFS and S3 (S3a/S3n).

Constructor Summary

Constructors

Constructor and Description
HadoopDataOutputStream(org.apache.hadoop.fs.FSDataOutputStream fdos)

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.
org.apache.hadoop.fs.FSDataOutputStream	getHadoopOutputStream() Gets the wrapped Hadoop 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.
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

write

Methods inherited from class java.lang.Object

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

Constructor Detail

HadoopDataOutputStream

public HadoopDataOutputStream(org.apache.hadoop.fs.FSDataOutputStream fdos)

Method Detail

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

close

public void close()
           throws IOException

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

Throws:

IOException - Thrown, if an error occurred while closing the stream or guaranteeing that the data is persistent.

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

getHadoopOutputStream

public org.apache.hadoop.fs.FSDataOutputStream getHadoopOutputStream()

Gets the wrapped Hadoop output stream.

Returns:

The wrapped Hadoop output stream.