org.apache.hadoop.fs

Interface StreamCapabilities

All Known Implementing Classes:

FSDataInputStream, FSDataOutputStream, HdfsDataInputStream, HdfsDataOutputStream

@InterfaceAudience.Public
 @InterfaceStability.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.

Field Summary

Fields

Modifier and Type	Field and Description
static String	DROPBEHIND Stream setDropBehind capability implemented by CanSetDropBehind.setDropBehind(Boolean).
static String	HFLUSH Stream hflush capability implemented by Syncable.hflush().
static String	HSYNC Stream hsync capability implemented by Syncable.hsync().
static String	PREADBYTEBUFFER Stream read(long, ByteBuffer) capability implemented by ByteBufferPositionedReadable.read(long, java.nio.ByteBuffer).
static String	READAHEAD Stream setReadahead capability implemented by CanSetReadahead.setReadahead(Long).
static String	READBYTEBUFFER Stream read(ByteBuffer) capability implemented by ByteBufferReadable.read(java.nio.ByteBuffer).
static String	UNBUFFER Stream unbuffer capability implemented by CanUnbuffer.unbuffer().

Method Summary

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

Field Detail

HFLUSH

static final String HFLUSH

Stream hflush capability implemented by Syncable.hflush().

See Also:

Constant Field Values

HSYNC

static final String HSYNC

Stream hsync capability implemented by Syncable.hsync().

See Also:

Constant Field Values

READAHEAD

static final String READAHEAD

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

See Also:

Constant Field Values

DROPBEHIND

static final String DROPBEHIND

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

See Also:

Constant Field Values

UNBUFFER

static final String UNBUFFER

Stream unbuffer capability implemented by CanUnbuffer.unbuffer().

See Also:

Constant Field Values

READBYTEBUFFER

static final String READBYTEBUFFER

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

See Also:

Constant Field Values

PREADBYTEBUFFER

static final String PREADBYTEBUFFER

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

See Also:

Constant Field Values

Method Detail

hasCapability

boolean hasCapability(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.