org.apache.hadoop.hbase.io.util

Interface Dictionary

All Known Implementing Classes:

LRUDictionary

@InterfaceAudience.Private
public interface Dictionary

Dictionary interface Dictionary indexes should be either bytes or shorts, only positive. (The first bit is reserved for detecting whether something is compressed or not).

Field Summary

Fields

Modifier and Type	Field and Description
static byte	NOT_IN_DICTIONARY

Method Summary

Modifier and Type	Method and Description
short	addEntry(byte[] data, int offset, int length) Adds an entry to the dictionary.
void	clear() Flushes the dictionary, empties all values.
short	findEntry(byte[] data, int offset, int length) Finds the index of an entry.
short	findEntry(ByteBuffer data, int offset, int length) Finds the index of an entry.
byte[]	getEntry(short idx) Gets an entry from the dictionary.
void	init(int initialSize)
static void	write(OutputStream out, byte[] data, int offset, int length, Dictionary dict) Helper methods to write the dictionary data to the OutputStream
static void	write(OutputStream out, ByteBuffer data, int offset, int length, Dictionary dict) Helper methods to write the dictionary data to the OutputStream

Field Detail

NOT_IN_DICTIONARY

static final byte NOT_IN_DICTIONARY

See Also:

Constant Field Values

Method Detail

init

void init(int initialSize)

getEntry

byte[] getEntry(short idx)

Gets an entry from the dictionary.

Parameters:

idx - index of the entry

Returns:

the entry, or null if non existent

findEntry

short findEntry(byte[] data,
                int offset,
                int length)

Finds the index of an entry. If no entry found, we add it.

Parameters:

data - the byte array that we're looking up

offset - Offset into data to add to Dictionary.

length - Length beyond offset that comprises entry; must be > 0.

Returns:

the index of the entry, or NOT_IN_DICTIONARY if not found

findEntry

short findEntry(ByteBuffer data,
                int offset,
                int length)

Finds the index of an entry. If no entry found, we add it.

Parameters:

data - the ByteBuffer that we're looking up

offset - Offset into data to add to Dictionary.

length - Length beyond offset that comprises entry; must be > 0.

Returns:

the index of the entry, or NOT_IN_DICTIONARY if not found

addEntry

short addEntry(byte[] data,
               int offset,
               int length)

Adds an entry to the dictionary. Be careful using this method. It will add an entry to the dictionary even if it already has an entry for the same data. Call {findEntry(byte[], int, int)} to add without duplicating dictionary entries.

Parameters:

data - the entry to add

offset - Offset into data to add to Dictionary.

length - Length beyond offset that comprises entry; must be > 0.

Returns:

the index of the entry

clear

void clear()

Flushes the dictionary, empties all values.

write

static void write(OutputStream out,
                  byte[] data,
                  int offset,
                  int length,
                  Dictionary dict)
           throws IOException

Helper methods to write the dictionary data to the OutputStream

Parameters:

out - the outputstream to which data needs to be written

data - the data to be written in byte[]

offset - the offset

length - length to be written

dict - the dictionary whose contents are to written

Throws:

IOException

write

static void write(OutputStream out,
                  ByteBuffer data,
                  int offset,
                  int length,
                  Dictionary dict)
           throws IOException

Helper methods to write the dictionary data to the OutputStream

Parameters:

out - the outputstream to which data needs to be written

data - the data to be written in ByteBuffer

offset - the offset

length - length to be written

dict - the dictionary whose contents are to written

Throws:

IOException