DeflaterInputStream

AI-generated Key Takeaways

• DeflaterInputStream compresses data in the "deflate" format, reading from an underlying input stream and providing compressed data.

• It provides constructors to initialize with a default or custom Deflater and buffer size.

• The read() methods allow reading compressed data into a byte array or as individual bytes.

• Methods like mark() and reset() are not supported, while close() releases resources.

• available() indicates data availability (1 if data is available, 0 if EOF is reached).

public class DeflaterInputStream extends FilterInputStream

Implements an input stream filter for compressing data in the "deflate" compression format.

See Also

• DeflaterOutputStream
• InflaterOutputStream
• InflaterInputStream

Field Summary

protected final byte[]	buf	Input buffer for reading compressed data.
protected final Deflater	def	Compressor for this stream.

Inherited Field Summary

From class java.io.FilterInputStream

protected InputStream

in

The input stream to be filtered.

Public Constructor Summary

	DeflaterInputStream(InputStream in) Creates a new input stream with a default compressor and buffer size.
	DeflaterInputStream(InputStream in, Deflater defl) Creates a new input stream with the specified compressor and a default buffer size.
	DeflaterInputStream(InputStream in, Deflater defl, int bufLen) Creates a new input stream with the specified compressor and buffer size.

Public Method Summary

int	available() Returns 0 after EOF has been reached, otherwise always return 1.
void	close() Closes this input stream and its underlying input stream, discarding any pending uncompressed data.
void	mark(int limit) This operation is not supported.
boolean	markSupported() Always returns false because this input stream does not support the mark() and reset() methods.
int	read() Reads a single byte of compressed data from the input stream.
int	read(byte[] b, int off, int len) Reads compressed data into a byte array.
void	reset() This operation is not supported.
long	skip(long n) Skips over and discards data from the input stream.

Inherited Method Summary

From class java.io.FilterInputStream

int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
synchronized void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
int	read() Reads the next byte of data from this input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from this input stream into an array of bytes.
int	read(byte[] b) Reads up to byte.length bytes of data from this input stream into an array of bytes.
synchronized void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips over and discards n bytes of data from the input stream.

From class java.io.InputStream

int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
synchronized void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
abstract int	read() Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
synchronized void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips over and discards n bytes of data from this input stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.io.Closeable

abstract void

close() Closes this stream and releases any system resources associated with it.

From interface java.lang.AutoCloseable

abstract void

close() Closes this resource, relinquishing any underlying resources.

Fields

protected final byte[] buf

Input buffer for reading compressed data.

protected final Deflater def

Compressor for this stream.

Public Constructors

public DeflaterInputStream (InputStream in)

Creates a new input stream with a default compressor and buffer size.

Parameters

in	input stream to read the uncompressed data to

Throws

NullPointerException	if in is null

public DeflaterInputStream (InputStream in, Deflater defl)

Creates a new input stream with the specified compressor and a default buffer size.

Parameters

in	input stream to read the uncompressed data to
defl	compressor ("deflater") for this stream

Throws

NullPointerException	if in or defl is null

public DeflaterInputStream (InputStream in, Deflater defl, int bufLen)

Creates a new input stream with the specified compressor and buffer size.

Parameters

in	input stream to read the uncompressed data to
defl	compressor ("deflater") for this stream
bufLen	compression buffer size

Throws

IllegalArgumentException	if bufLen <= 0
NullPointerException	if in or defl is null

Public Methods

public int available ()

Returns 0 after EOF has been reached, otherwise always return 1.

Programs should not count on this method to return the actual number of bytes that could be read without blocking

Returns

• zero after the end of the underlying input stream has been reached, otherwise always returns 1

Throws

IOException	if an I/O error occurs or if this stream is already closed

public void close ()

Closes this input stream and its underlying input stream, discarding any pending uncompressed data.

Throws

IOException	if an I/O error occurs

public void mark (int limit)

This operation is not supported.

Parameters

limit	maximum bytes that can be read before invalidating the position marker

public boolean markSupported ()

Always returns false because this input stream does not support the mark() and reset() methods.

Returns

• false, always

public int read ()

Reads a single byte of compressed data from the input stream. This method will block until some input can be read and compressed.

Returns

• a single byte of compressed data, or -1 if the end of the uncompressed input stream is reached

Throws

IOException	if an I/O error occurs or if this stream is already closed

public int read (byte[] b, int off, int len)

Reads compressed data into a byte array. This method will block until some input can be read and compressed.

Parameters

b	buffer into which the data is read
off	starting offset of the data within b
len	maximum number of compressed bytes to read into b

Returns

• the actual number of bytes read, or -1 if the end of the uncompressed input stream is reached

Throws

IndexOutOfBoundsException	if len > b.length - off
IOException	if an I/O error occurs or if this input stream is already closed

public void reset ()

This operation is not supported.

Throws

IOException	always thrown

public long skip (long n)

Skips over and discards data from the input stream. This method may block until the specified number of bytes are read and skipped. Note: While n is given as a long, the maximum number of bytes which can be skipped is Integer.MAX_VALUE.

Parameters

n	number of bytes to be skipped

Returns

• the actual number of bytes skipped

Throws

IOException	if an I/O error occurs or if this stream is already closed