org.apache.druid.segment.data

Class CompressionStrategy.Compressor

java.lang.Object

org.apache.druid.segment.data.CompressionStrategy.Compressor

Direct Known Subclasses:

CompressionStrategy.LZ4Compressor, CompressionStrategy.LZFCompressor, CompressionStrategy.UncompressedCompressor, CompressionStrategy.ZstdCompressor

Enclosing class:

CompressionStrategy

public abstract static class CompressionStrategy.Compressor
extends Object

Constructor Summary

Constructors

Constructor and Description
Compressor()

Method Summary

Modifier and Type	Method and Description
ByteBuffer	allocateInBuffer(int inputSize, Closer closer) Allocates a buffer that should be passed to compress(java.nio.ByteBuffer, java.nio.ByteBuffer) method as input buffer.
abstract ByteBuffer	allocateOutBuffer(int inputSize, Closer closer) Allocates a buffer that should be passed to compress(java.nio.ByteBuffer, java.nio.ByteBuffer) method as output buffer.
abstract ByteBuffer	compress(ByteBuffer in, ByteBuffer out) Returns a ByteBuffer with compressed contents of in between it's position and limit.

Methods inherited from class java.lang.Object

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

Constructor Detail

Compressor

public Compressor()

Method Detail

allocateInBuffer

public ByteBuffer allocateInBuffer(int inputSize,
                                   Closer closer)

Allocates a buffer that should be passed to compress(java.nio.ByteBuffer, java.nio.ByteBuffer) method as input buffer. Different Compressors require (or work more efficiently with) different kinds of buffers.

If the allocated buffer is a direct buffer, it should be registered to be freed with the given Closer.

allocateOutBuffer

public abstract ByteBuffer allocateOutBuffer(int inputSize,
                                             Closer closer)

Allocates a buffer that should be passed to compress(java.nio.ByteBuffer, java.nio.ByteBuffer) method as output buffer. Different Compressors require (or work more efficiently with) different kinds of buffers.

Allocates a buffer that is always enough to compress a byte sequence of the given size.

If the allocated buffer is a direct buffer, it should be registered to be freed with the given Closer.

compress

public abstract ByteBuffer compress(ByteBuffer in,
                                    ByteBuffer out)

Returns a ByteBuffer with compressed contents of in between it's position and limit. It may be the provided out ByteBuffer, or the in ByteBuffer, depending on the implementation. out's position and limit are not respected and could be discarded.

Contents of in between it's position and limit are compressed. It's contents, position and limit shouldn't be changed in compress() method.