org.apache.iotdb.tsfile.encoding.encoder

Class BitmapEncoder

java.lang.Object

org.apache.iotdb.tsfile.encoding.encoder.Encoder

org.apache.iotdb.tsfile.encoding.encoder.BitmapEncoder

public class BitmapEncoder
extends Encoder

Encodes values using bitmap, according to the following grammar:

 bitmap-encoding: <length> <num> <encoded-data>
 length := length of the <encoded-data> in bytes stored as unsigned var int
 num := number for all encoded data in <encoded-data> stored as unsigned var int
 encoded-data := <run>*
 run := <value> <bit-index>
 value := value in the data after deduplication. Use varint-encode and store as unsigned var int
 bit-index := a list of 01 sequence to record the position of the value above
 

.

Decode switch or enum values using bitmap, bitmap-encode.<length> <num> <encoded data>

Field Summary

Fields inherited from class org.apache.iotdb.tsfile.encoding.encoder.Encoder

MAX_POINT_NUMBER, MAX_STRING_LENGTH

Constructor Summary

Constructors

Constructor and Description
BitmapEncoder() BitmapEncoder constructor.

Method Summary

Modifier and Type	Method and Description
void	encode(int value, ByteArrayOutputStream out) Each time encoder receives a value, encoder doesn't write it to OutputStream immediately.
void	flush(ByteArrayOutputStream out) When all data received, encoder now encodes values in list and write them to OutputStream.
long	getMaxByteSize() The maximal possible memory size occupied by current Encoder.
int	getOneItemMaxSize() When encoder accepts a new incoming data point, the maximal possible size in byte it takes to store in memory.

Methods inherited from class org.apache.iotdb.tsfile.encoding.encoder.Encoder

encode, encode, encode, encode, encode, encode, encode, getType, setType

Methods inherited from class java.lang.Object

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

Constructor Detail

BitmapEncoder

public BitmapEncoder()

BitmapEncoder constructor.

Method Detail

encode

public void encode(int value,
                   ByteArrayOutputStream out)

Each time encoder receives a value, encoder doesn't write it to OutputStream immediately. Encoder stores current value in a list. When all value is received, flush() method will be invoked. Encoder encodes all values and writes them to OutputStream.

Overrides:

encode in class Encoder

Parameters:

value - value to encode

out - OutputStream to write encoded stream

Throws:

IOException - cannot encode value

See Also:

Encoder.encode(int, java.io.ByteArrayOutputStream)

flush

public void flush(ByteArrayOutputStream out)
           throws IOException

When all data received, encoder now encodes values in list and write them to OutputStream.

Specified by:

flush in class Encoder

Parameters:

out - OutputStream to write encoded stream

Throws:

IOException - cannot flush to OutputStream

See Also:

Encoder.flush(java.io.ByteArrayOutputStream)

getOneItemMaxSize

public int getOneItemMaxSize()

Description copied from class: Encoder

When encoder accepts a new incoming data point, the maximal possible size in byte it takes to store in memory.

Overrides:

getOneItemMaxSize in class Encoder

Returns:

the maximal possible size of one data item encoded by this encoder

getMaxByteSize

public long getMaxByteSize()

Description copied from class: Encoder

The maximal possible memory size occupied by current Encoder. This statistic value doesn't involve OutputStream.

Overrides:

getMaxByteSize in class Encoder

Returns:

the maximal size of possible memory occupied by current encoder