Package org.apache.commons.compress.compressors.gzip

Class GzipCompressorOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

org.apache.commons.compress.CompressFilterOutputStream<OutputStream>

org.apache.commons.compress.compressors.CompressorOutputStream<OutputStream>

org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class GzipCompressorOutputStream
extends CompressorOutputStream<OutputStream>

Compressed output stream using the gzip format. This implementation improves over the standard GZIPOutputStream class by allowing the configuration of the compression level and the header metadata (file name, comment, modification time, operating system and extra flags).

See Also:

• RFC 1952 GZIP File Format Specification

Field Summary

Fields

Modifier and Type	Field	Description
private final CRC32	crc	The checksum of the uncompressed data
private final byte[]	deflateBuffer	The buffer receiving the compressed data from the deflater
private final Deflater	deflater	Deflater used to compress the data

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor	Description
GzipCompressorOutputStream(OutputStream out)	Creates a gzip compressed output stream with the default parameters.
GzipCompressorOutputStream(OutputStream out, GzipParameters parameters)	Creates a gzip compressed output stream with the specified parameters.

Method Summary

Modifier and Type	Method	Description
void	close()
private void	deflate()
void	finish()	Finishes writing compressed data to the underlying stream without closing it.
void	write(byte[] buffer)
void	write(byte[] buffer, int offset, int length)
void	write(int b)
private void	writeC(String value, Charset charset)	Writes a C-style string, a NUL-terminated string, encoded with the charset.
private void	writeMemberHeader(GzipParameters parameters)
private void	writeMemberTrailer()	Writes the member trailer.

Methods inherited from class org.apache.commons.compress.CompressFilterOutputStream

checkOpen, isClosed, isFinished, out, write, write, writeUsAscii, writeUsAsciiRaw, writeUtf8

Methods inherited from class java.io.FilterOutputStream

flush

Methods inherited from class java.lang.Object

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

Field Details

deflater

private final Deflater deflater

Deflater used to compress the data

deflateBuffer

private final byte[] deflateBuffer

The buffer receiving the compressed data from the deflater

crc

private final CRC32 crc

The checksum of the uncompressed data

Constructor Details

GzipCompressorOutputStream

public GzipCompressorOutputStream(OutputStream out)
                           throws IOException

Creates a gzip compressed output stream with the default parameters.

Parameters:

out - the stream to compress to

Throws:

IOException - if writing fails

GzipCompressorOutputStream

public GzipCompressorOutputStream(OutputStream out,
 GzipParameters parameters)
                           throws IOException

Creates a gzip compressed output stream with the specified parameters.

Parameters:

out - the stream to compress to

parameters - the parameters to use

Throws:

IOException - if writing fails

Since:

1.7

Method Details

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class CompressFilterOutputStream<OutputStream>

Throws:

IOException

deflate

private void deflate()
              throws IOException

Throws:

IOException

finish

public void finish()
            throws IOException

Finishes writing compressed data to the underlying stream without closing it.

Overrides:

finish in class CompressFilterOutputStream<OutputStream>

Throws:

IOException - on error

Since:

1.7

write

public void write(byte[] buffer)
           throws IOException

Overrides:

write in class FilterOutputStream

Throws:

IOException

Since:

1.1

write

public void write(byte[] buffer,
 int offset,
 int length)
           throws IOException

Overrides:

write in class FilterOutputStream

Throws:

IOException

Since:

1.1

write

public void write(int b)
           throws IOException

Overrides:

write in class FilterOutputStream

Throws:

IOException

writeC

private void writeC(String value,
 Charset charset)
             throws IOException

Writes a C-style string, a NUL-terminated string, encoded with the charset.

Parameters:

value - The String to write.

charset - Specifies the Charset to use.

Throws:

IOException - if an I/O error occurs.

writeMemberHeader

private void writeMemberHeader(GzipParameters parameters)
                        throws IOException

Throws:

IOException

writeMemberTrailer

private void writeMemberTrailer()
                         throws IOException

Writes the member trailer.

      0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   |     CRC32     |     ISIZE     |
   +---+---+---+---+---+---+---+---+
 

Throws:

IOException - if an I/O error occurs.