Class GZIPOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

java.util.zip.DeflaterOutputStream

java.util.zip.GZIPOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class GZIPOutputStream
extends DeflaterOutputStream

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

Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.

Since:

1.1

Field Summary

Fields

Modifier and Type	Field	Description
protected CRC32	crc	CRC-32 of uncompressed data.

Fields declared in class DeflaterOutputStream

buf, def

Modifier and Type	Field	Description
protected byte[]	buf	Output buffer for writing compressed data.
protected Deflater	def	Compressor for this stream.

Fields declared in class FilterOutputStream

out

Modifier and Type	Field	Description
protected OutputStream	out	The underlying output stream to be filtered.

Constructor Summary

Constructors

Constructor	Description
GZIPOutputStream(OutputStream out)	Creates a new output stream with a default buffer size.
GZIPOutputStream(OutputStream out, boolean syncFlush)	Creates a new output stream with a default buffer size and the specified flush mode.
GZIPOutputStream(OutputStream out, int size)	Creates a new output stream with the specified buffer size.
GZIPOutputStream(OutputStream out, int size, boolean syncFlush)	Creates a new output stream with the specified buffer size and flush mode.

Method Summary

Modifier and Type	Method	Description
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.

Methods declared in class DeflaterOutputStream

close, deflate, flush, write

Modifier and Type	Method	Description
void	close()	Writes remaining compressed data to the output stream and closes the underlying stream.
protected void	deflate()	Writes next block of compressed data to the output stream.
void	flush()	Flushes the compressed output stream.
void	write(int b)	Writes a byte to the compressed output stream.

Methods declared in class FilterOutputStream

write

Modifier and Type	Method	Description
void	write(byte[] b)	Writes b.length bytes to this output stream.

Methods declared in class OutputStream

nullOutputStream

Modifier and Type	Method	Description
static OutputStream	nullOutputStream()	Returns a new OutputStream which discards all bytes.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Field Details

crc

protected CRC32 crc

CRC-32 of uncompressed data.

Constructor Details

GZIPOutputStream

public GZIPOutputStream(OutputStream out,
 int size)
                 throws IOException

Creates a new output stream with the specified buffer size.

The new output stream instance is created as if by invoking the 3-argument constructor GZIPOutputStream(out, size, false).

Parameters:

out - the output stream

size - the output buffer size

Throws:

IOException - If an I/O error has occurred.

IllegalArgumentException - if size <= 0

GZIPOutputStream

public GZIPOutputStream(OutputStream out,
 int size,
 boolean syncFlush)
                 throws IOException

Creates a new output stream with the specified buffer size and flush mode.

Parameters:

out - the output stream

size - the output buffer size

syncFlush - if true invocation of the inherited flush() method of this instance flushes the compressor with flush mode Deflater.SYNC_FLUSH before flushing the output stream, otherwise only flushes the output stream

Throws:

IOException - If an I/O error has occurred.

IllegalArgumentException - if size <= 0

Since:

1.7

GZIPOutputStream

public GZIPOutputStream(OutputStream out)
                 throws IOException

Creates a new output stream with a default buffer size.

The new output stream instance is created as if by invoking the 2-argument constructor GZIPOutputStream(out, false).

Parameters:

out - the output stream

Throws:

IOException - If an I/O error has occurred.

GZIPOutputStream

public GZIPOutputStream(OutputStream out,
 boolean syncFlush)
                 throws IOException

Creates a new output stream with a default buffer size and the specified flush mode.

Parameters:

out - the output stream

syncFlush - if true invocation of the inherited flush() method of this instance flushes the compressor with flush mode Deflater.SYNC_FLUSH before flushing the output stream, otherwise only flushes the output stream

Throws:

IOException - If an I/O error has occurred.

Since:

1.7

Method Details

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.

See Also:

• FilterOutputStream.write(int)

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