Package org.apache.commons.compress.compressors.snappy

# Class SnappyCompressorOutputStream

java.lang.Object
java.io.OutputStream
org.apache.commons.compress.compressors.CompressorOutputStream
org.apache.commons.compress.compressors.snappy.SnappyCompressorOutputStream

All Implemented Interfaces:
  `Closeable`, `Flushable`, `AutoCloseable`

public class SnappyCompressorOutputStream extends CompressorOutputStream
CompressorOutputStream for the raw Snappy format.

This implementation uses an internal buffer in order to handle the back-references that are at the heart of the LZ77 algorithm. The size of the buffer must be at least as big as the biggest offset used in the compressed stream. The current version of the Snappy algorithm as defined by Google works on 32k blocks and doesn't contain offsets bigger than 32k which is the default block size used by this class.

The raw Snappy format requires the uncompressed size to be written at the beginning of the stream using a varint representation, i.e. the number of bytes needed to write the information is not known before the uncompressed size is known. We've chosen to make the uncompressedSize a parameter of the constructor in favor of buffering the whole output until the size is known. When using the `FramedSnappyCompressorOutputStream` this limitation is taken care of by the warpping framing format.

Since:
  1.14
See Also:
  - Snappy compressed format description
This class is not thread-safe

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `SnappyCompressorOutputStream(OutputStream os, long uncompressedSize)`
  Constructor using the default block size of 32k.
  `SnappyCompressorOutputStream(OutputStream os, long uncompressedSize, int blockSize)`
  Constructor using a configurable block size.
  `SnappyCompressorOutputStream(OutputStream os, long uncompressedSize, Parameters params)`
  Constructor providing full control over the underlying LZ77 compressor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `close()`
  `static Parameters.Builder`
  `createParameterBuilder(int blockSize)`
  Returns a builder correctly configured for the Snappy algorithm using the gven block size.
  `void`
  `finish()`
  Compresses all remaining data and writes it to the stream, doesn't close the underlying stream.
  `void`
  `write(byte[] data, int off, int len)`
  `void`
  `write(int b)`

  ### Methods inherited from class java.io.OutputStream

  `flush, write`

  ### Methods inherited from class java.lang.Object

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

- ## Constructor Details

  - ### SnappyCompressorOutputStream

    public SnappyCompressorOutputStream(OutputStream os, long uncompressedSize) throws IOException
    Constructor using the default block size of 32k.
    Parameters:
      `os` - the outputstream to write compressed data to
      `uncompressedSize` - the uncompressed size of data
    Throws:
      `IOException` - if writing of the size fails

  - ### SnappyCompressorOutputStream

    public SnappyCompressorOutputStream(OutputStream os, long uncompressedSize, int blockSize) throws IOException
    Constructor using a configurable block size.
    Parameters:
      `os` - the outputstream to write compressed data to
      `uncompressedSize` - the uncompressed size of data
      `blockSize` - the block size used - must be a power of two
    Throws:
      `IOException` - if writing of the size fails

  - ### SnappyCompressorOutputStream

    public SnappyCompressorOutputStream(OutputStream os, long uncompressedSize, Parameters params) throws IOException
    Constructor providing full control over the underlying LZ77 compressor.
    Parameters:
      `os` - the outputstream to write compressed data to
      `uncompressedSize` - the uncompressed size of data
      `params` - the parameters to use by the compressor - note that the format itself imposes some limits like a maximum match length of 64 bytes
    Throws:
      `IOException` - if writing of the size fails

- ## Method Details

  - ### createParameterBuilder

    public static Parameters.Builder createParameterBuilder(int blockSize)
    Returns a builder correctly configured for the Snappy algorithm using the gven block size.
    Parameters:
      `blockSize` - the block size.
    Returns:
      a builder correctly configured for the Snappy algorithm using the gven block size

  - ### close

    public void close() throws IOException
    Specified by:
      `close` in interface `AutoCloseable`
    Specified by:
      `close` in interface `Closeable`
    Overrides:
      `close` in class `OutputStream`
    Throws:
      `IOException`

  - ### finish

    public void finish() throws IOException
    Compresses all remaining data and writes it to the stream, doesn't close the underlying stream.
    Throws:
      `IOException` - if an error occurs

  - ### write

    public void write(byte[] data, int off, int len) throws IOException
    Overrides:
      `write` in class `OutputStream`
    Throws:
      `IOException`

  - ### write

    public void write(int b) throws IOException
    Specified by:
      `write` in class `OutputStream`
    Throws:
      `IOException`