java.util.zip
Class GZIPOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FilterOutputStream
          java.util.zip.DeflaterOutputStream
              java.util.zip.GZIPOutputStream

public class GZIPOutputStream

extends DeflaterOutputStream

This class implements a stream filter for writing compressed data in the GZIP file format.

Author:

David Connelly

Field Summary

protected CRC32	crc CRC-32 of uncompressed data.
private static int	GZIP_MAGIC
private static byte[]	header
private static int	TRAILER_SIZE

Fields inherited from class java.util.zip.DeflaterOutputStream

buf, def, usesDefaultDeflater

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

GZIPOutputStream(OutputStream out)
Creates a new output stream with a default buffer size.

GZIPOutputStream(OutputStream out, int size)
Creates a new output stream with the specified buffer size.

Method Summary

void	finish() Finishes writing compressed data to the output stream without closing the underlying stream.
void	write(byte[] buf, int off, int len) Writes array of bytes to the compressed output stream.
private void	writeHeader()
private void	writeInt(int i, byte[] buf, int offset)
private void	writeShort(int s, byte[] buf, int offset)
private void	writeTrailer(byte[] buf, int offset)

Methods inherited from class java.util.zip.DeflaterOutputStream

close, deflate, write

Methods inherited from class java.io.FilterOutputStream

flush, write

Methods inherited from class java.lang.Object

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

Field Detail

crc

protected CRC32 crc

CRC-32 of uncompressed data.

GZIP_MAGIC

private static final int GZIP_MAGIC

See Also:

Constant Field Values

TRAILER_SIZE

private static final int TRAILER_SIZE

See Also:

Constant Field Values

header

private static final byte[] header

Constructor Detail

GZIPOutputStream

public GZIPOutputStream(OutputStream out,
                        int size)
                 throws IOException

Creates a new output stream with the specified buffer size.

Parameters:

out - the output stream

size - the output buffer size

Throws:

IOException - If an I/O error has occurred.

IllegalArgumentException - if size is <= 0

GZIPOutputStream

public GZIPOutputStream(OutputStream out)
                 throws IOException

Creates a new output stream with a default buffer size.

Parameters:

out - the output stream

Throws:

IOException - If an I/O error has occurred.

Method Detail

write

public void write(byte[] buf,
                  int off,
                  int len)
           throws IOException

Writes array of bytes to the compressed output stream. This method will block until all the bytes are written.

Overrides:

write in class DeflaterOutputStream

Parameters:

buf - the data to be written

off - the start offset of the data

len - the length of the data

Throws:

IOException - If an I/O error has occurred.

finish

public void finish()
            throws IOException

Finishes writing compressed data to the output stream without closing the underlying stream. Use this method when applying multiple filters in succession to the same output stream.

Overrides:

finish in class DeflaterOutputStream

Throws:

IOException - if an I/O error has occurred

writeHeader

private void writeHeader()
                  throws IOException

Throws:

IOException

writeTrailer

private void writeTrailer(byte[] buf,
                          int offset)
                   throws IOException

Throws:

IOException

writeInt

private void writeInt(int i,
                      byte[] buf,
                      int offset)
               throws IOException

Throws:

IOException

writeShort

private void writeShort(int s,
                        byte[] buf,
                        int offset)
                 throws IOException

Throws:

IOException