org.apache.hadoop.fs.statistics

Class BufferedIOStatisticsOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

java.io.BufferedOutputStream

org.apache.hadoop.fs.statistics.BufferedIOStatisticsOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable, IOStatisticsSource, StreamCapabilities, Syncable

public class BufferedIOStatisticsOutputStream
extends BufferedOutputStream
implements IOStatisticsSource, Syncable, StreamCapabilities

An extension of BufferedOutputStream which implements IOStatisticsSource and forwards requests for the IOStatistics to the wrapped stream. This should be used when any output stream needs buffering while allowing the inner stream to be a source of statistics. It also implements StreamCapabilities and Syncable and forwards to to the inner stream, if possible.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.fs.StreamCapabilities

StreamCapabilities.StreamCapability

Field Summary

Fields inherited from class java.io.BufferedOutputStream

buf, count

Fields inherited from class java.io.FilterOutputStream

out

Fields inherited from interface org.apache.hadoop.fs.StreamCapabilities

ABORTABLE_STREAM, DROPBEHIND, HFLUSH, HSYNC, IOSTATISTICS, PREADBYTEBUFFER, READAHEAD, READBYTEBUFFER, UNBUFFER

Constructor Summary

Constructors

Constructor and Description
BufferedIOStatisticsOutputStream(OutputStream out, boolean downgradeSyncable) Construct with default buffer size.
BufferedIOStatisticsOutputStream(OutputStream out, int size, boolean downgradeSyncable) Construct with custom buffer size.

Method Summary

Modifier and Type	Method and Description
IOStatistics	getIOStatistics() Ask the inner stream for their IOStatistics.
boolean	hasCapability(String capability) If the inner stream supports StreamCapabilities, forward the probe to it.
void	hflush() If the inner stream is Syncable, flush the buffer and then invoke the inner stream's hflush() operation.
void	hsync() If the inner stream is Syncable, flush the buffer and then invoke the inner stream's hsync() operation.

Methods inherited from class java.io.BufferedOutputStream

flush, write, write

Methods inherited from class java.io.FilterOutputStream

close, write

Methods inherited from class java.lang.Object

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

Constructor Detail

BufferedIOStatisticsOutputStream

public BufferedIOStatisticsOutputStream(OutputStream out,
                                        boolean downgradeSyncable)

Construct with default buffer size.

Parameters:

out - output stream to buffer

downgradeSyncable - should Syncable calls downgrade?

BufferedIOStatisticsOutputStream

public BufferedIOStatisticsOutputStream(OutputStream out,
                                        int size,
                                        boolean downgradeSyncable)

Construct with custom buffer size.

Parameters:

out - output stream to buffer

size - buffer.

downgradeSyncable - should Syncable calls downgrade?

Method Detail

getIOStatistics

public IOStatistics getIOStatistics()

Ask the inner stream for their IOStatistics.

Specified by:

getIOStatistics in interface IOStatisticsSource

Returns:

any IOStatistics offered by the inner stream.

hasCapability

public boolean hasCapability(String capability)

If the inner stream supports StreamCapabilities, forward the probe to it. Otherwise: return false.

Specified by:

hasCapability in interface StreamCapabilities

Parameters:

capability - string to query the stream support for.

Returns:

true if a capability is known to be supported.

hflush

public void hflush()
            throws IOException

If the inner stream is Syncable, flush the buffer and then invoke the inner stream's hflush() operation. Otherwise: throw an exception, unless the stream was constructed with downgradeSyncable set to true, in which case the stream is just flushed.

Specified by:

hflush in interface Syncable

Throws:

IOException - IO Problem

UnsupportedOperationException - if the inner class is not syncable

hsync

public void hsync()
           throws IOException

If the inner stream is Syncable, flush the buffer and then invoke the inner stream's hsync() operation. Otherwise: throw an exception, unless the stream was constructed with downgradeSyncable set to true, in which case the stream is just flushed.

Specified by:

hsync in interface Syncable

Throws:

IOException - IO Problem

UnsupportedOperationException - if the inner class is not syncable