Package org.apache.hadoop.hbase

Interface Tag

All Known Implementing Classes:

ArrayBackedTag, ByteBufferTag

@LimitedPrivate("Coprocesssor")
@Evolving
public interface Tag

Tags are part of cells and helps to add metadata about them. Metadata could be ACLs, visibility labels, etc.

Each Tag is having a type (one byte) and value part. The max value length for a Tag is 65533.

See TagType for reserved tag types.

Field Summary

Fields

Modifier and Type	Field	Description
static final byte	CUSTOM_TAG_TYPE_RANGE	Custom tags if created are suggested to be above this range.
static final int	INFRASTRUCTURE_SIZE
static final int	MAX_TAG_LENGTH
static final int	TAG_LENGTH_SIZE
static final int	TYPE_LENGTH_SIZE

Method Summary

Modifier and Type	Method	Description
static byte[]	cloneValue(Tag tag)	Returns tag value in a new byte array.
static void	copyValueTo(Tag tag, byte[] out, int offset)	Copies the tag's value bytes to the given byte array
byte	getType()	Returns the tag type
byte[]	getValueArray()	Return an array containing the value bytes if hasArray() returns true.
static byte	getValueAsByte(Tag tag)	Converts the value bytes of the given tag into a byte value
static long	getValueAsLong(Tag tag)	Converts the value bytes of the given tag into a long value
static String	getValueAsString(Tag tag)	Converts the value bytes of the given tag into a String value
ByteBuffer	getValueByteBuffer()	Returns The ByteBuffer containing the value bytes.
int	getValueLength()	Returns Length of tag value within the backed buffer
int	getValueOffset()	Returns Offset of tag value within the backed buffer
boolean	hasArray()	Return true if the tag is backed by a byte array
static boolean	matchingValue(Tag t1, Tag t2)	Matches the value part of given tags

Field Details

TYPE_LENGTH_SIZE

static final int TYPE_LENGTH_SIZE

See Also:

• Constant Field Values

TAG_LENGTH_SIZE

static final int TAG_LENGTH_SIZE

See Also:

• Constant Field Values

INFRASTRUCTURE_SIZE

static final int INFRASTRUCTURE_SIZE

See Also:

• Constant Field Values

MAX_TAG_LENGTH

static final int MAX_TAG_LENGTH

See Also:

• Constant Field Values

CUSTOM_TAG_TYPE_RANGE

static final byte CUSTOM_TAG_TYPE_RANGE

Custom tags if created are suggested to be above this range. So that it does not overlap with internal tag types

See Also:

• Constant Field Values

Method Details

getType

byte getType()

Returns the tag type

getValueOffset

int getValueOffset()

Returns Offset of tag value within the backed buffer

getValueLength

int getValueLength()

Returns Length of tag value within the backed buffer

hasArray

boolean hasArray()

Return true if the tag is backed by a byte array

getValueArray

byte[] getValueArray()

Return an array containing the value bytes if hasArray() returns true.

Use getValueByteBuffer() otherwise.

getValueByteBuffer

ByteBuffer getValueByteBuffer()

Returns The ByteBuffer containing the value bytes.

cloneValue

static byte[] cloneValue(Tag tag)

Returns tag value in a new byte array. Primarily for use client-side. If server-side, use getValueArray() with appropriate getValueOffset() and getValueLength() instead to save on allocations.

Parameters:

tag - The Tag whose value to be returned

Returns:

tag value in a new byte array.

getValueAsString

static String getValueAsString(Tag tag)

Converts the value bytes of the given tag into a String value

Parameters:

tag - The Tag

Returns:

value as String

matchingValue

static boolean matchingValue(Tag t1,
 Tag t2)

Matches the value part of given tags

Parameters:

t1 - Tag to match the value

t2 - Tag to match the value

Returns:

True if values of both tags are same.

copyValueTo

static void copyValueTo(Tag tag,
 byte[] out,
 int offset)

Copies the tag's value bytes to the given byte array

Parameters:

tag - The Tag

out - The byte array where to copy the Tag value.

offset - The offset within 'out' array where to copy the Tag value.

getValueAsLong

static long getValueAsLong(Tag tag)

Converts the value bytes of the given tag into a long value

Parameters:

tag - The Tag

Returns:

value as long

getValueAsByte

static byte getValueAsByte(Tag tag)

Converts the value bytes of the given tag into a byte value

Parameters:

tag - The Tag

Returns:

value as byte