Package org.apache.hadoop.fs

Interface StreamCapabilities

All Known Implementing Classes:

BufferedFSInputStream, BufferedIOStatisticsInputStream, BufferedIOStatisticsOutputStream, CryptoFSDataInputStream, CryptoFSDataOutputStream, CryptoInputStream, CryptoOutputStream, FlagSet, FSDataInputStream, FSDataOutputStream, FSOutputSummer, SequenceFile.Writer

@Public
@Evolving
public interface StreamCapabilities

Interface to query streams for supported capabilities. Capability strings must be in lower case. Constant strings are chosen over enums in order to allow other file systems to define their own capabilities.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	StreamCapabilities.StreamCapability	Deprecated.

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	ABORTABLE_STREAM	Stream abort() capability implemented by Abortable.abort().
static java.lang.String	DROPBEHIND	Stream setDropBehind capability implemented by CanSetDropBehind.setDropBehind(Boolean).
static java.lang.String	HFLUSH	Deprecated.
static java.lang.String	HSYNC	Stream hsync capability implemented by Syncable.hsync().
static java.lang.String	IOSTATISTICS	IOStatisticsSource API.
static java.lang.String	IOSTATISTICS_CONTEXT	Streams that support IOStatistics context and capture thread-level IOStatistics.
static java.lang.String	PREADBYTEBUFFER	Stream read(long, ByteBuffer) capability implemented by ByteBufferPositionedReadable.read(long, java.nio.ByteBuffer).
static java.lang.String	READAHEAD	Stream setReadahead capability implemented by CanSetReadahead.setReadahead(Long).
static java.lang.String	READBYTEBUFFER	Stream read(ByteBuffer) capability implemented by ByteBufferReadable.read(java.nio.ByteBuffer).
static java.lang.String	UNBUFFER	Stream unbuffer capability implemented by CanUnbuffer.unbuffer().
static java.lang.String	VECTOREDIO	Support for vectored IO api.

Method Summary

Modifier and Type	Method	Description
boolean	hasCapability(java.lang.String capability)	Query the stream for a specific capability.

Field Detail

HFLUSH

@Deprecated
static final java.lang.String HFLUSH

Deprecated.

Stream hflush capability implemented by Syncable.hflush(). Use the HSYNC probe to check for the support of Syncable; it's that presence of hsync() which matters.

See Also:

Constant Field Values

HSYNC

static final java.lang.String HSYNC

Stream hsync capability implemented by Syncable.hsync().

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Constant Field Values

READAHEAD

static final java.lang.String READAHEAD

Stream setReadahead capability implemented by CanSetReadahead.setReadahead(Long).

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Constant Field Values

DROPBEHIND

static final java.lang.String DROPBEHIND

Stream setDropBehind capability implemented by CanSetDropBehind.setDropBehind(Boolean).

See Also:

Constant Field Values

UNBUFFER

static final java.lang.String UNBUFFER

Stream unbuffer capability implemented by CanUnbuffer.unbuffer().

See Also:

Constant Field Values

READBYTEBUFFER

static final java.lang.String READBYTEBUFFER

Stream read(ByteBuffer) capability implemented by ByteBufferReadable.read(java.nio.ByteBuffer).

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Constant Field Values

PREADBYTEBUFFER

static final java.lang.String PREADBYTEBUFFER

Stream read(long, ByteBuffer) capability implemented by ByteBufferPositionedReadable.read(long, java.nio.ByteBuffer).

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Constant Field Values

IOSTATISTICS

static final java.lang.String IOSTATISTICS

IOStatisticsSource API.

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Constant Field Values

VECTOREDIO

static final java.lang.String VECTOREDIO

Support for vectored IO api. See PositionedReadable#readVectored(List, IntFunction).

See Also:

Constant Field Values

ABORTABLE_STREAM

static final java.lang.String ABORTABLE_STREAM

Stream abort() capability implemented by Abortable.abort(). This matches the Path Capability CommonPathCapabilities.ABORTABLE_STREAM.

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Constant Field Values

IOSTATISTICS_CONTEXT

static final java.lang.String IOSTATISTICS_CONTEXT

Streams that support IOStatistics context and capture thread-level IOStatistics.

See Also:

Constant Field Values

Method Detail

hasCapability

boolean hasCapability(java.lang.String capability)

Query the stream for a specific capability.

Parameters:

capability - string to query the stream support for.

Returns:

True if the stream supports capability.