Class DeflaterInputStream

java.util.zip.DeflaterInputStream

All Implemented Interfaces:: Closeable, AutoCloseable

public class DeflaterInputStream extends FilterInputStream

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

Compressor Usage

A DeflaterInputStream created without specifying a compressor will create a compressor at construction time, and close the compressor when the input stream is closed.

If a compressor is specified when creating a DeflaterInputStream, it is the responsibility of the caller to close the compressor after closing the input stream.

API Note:

The close() method should be called to release resources used by this stream, either directly, or with the try-with-resources statement.

Since:

1.6

See Also:

Field Summary

Modifier and Type	Field	Description
`protected final byte[]`	`buf`	Input buffer for reading compressed data.
`protected final Deflater`	`def`	Compressor for this stream.

Fields declared in class FilterInputStream

in

Constructor Summary

Constructor	Description
`DeflaterInputStream(InputStream in)`	Creates a new input stream and compressor with the default compression level and a default 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.

Method Summary

Modifier and Type	Method	Description
`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.

Methods declared in class FilterInputStream

read

Methods declared in class InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Methods declared in class Object

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

Field Details

def

protected final Deflater def

Compressor for this stream.

buf

protected final byte[] buf

Input buffer for reading compressed data.

Constructor Details

DeflaterInputStream

public DeflaterInputStream(InputStream in)

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

The compressor will be closed when this input stream is closed.

Parameters:: in - input stream to read the uncompressed data to
Throws:: NullPointerException - if in is null

DeflaterInputStream

public DeflaterInputStream(InputStream in, Deflater defl)

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

Closing this input stream will not close the given compressor.

Parameters:: in - input stream to read the uncompressed data to; defl - compressor ("deflater") for this stream
Throws:: NullPointerException - if in or defl is null

DeflaterInputStream

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

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

Closing this input stream will not close the given compressor.

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

Method Details

close

public void close() throws IOException

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

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterInputStream

Throws:

IOException - if an I/O error occurs

See Also:

read

public int read() throws IOException

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

Overrides:

read in class FilterInputStream

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

See Also:

read

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

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

Overrides:

read in class FilterInputStream

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:

NullPointerException - if b is null

IndexOutOfBoundsException - if len > b.length - off

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

See Also:

skip

public long skip(long n) throws IOException

Skips over and discards data from the input stream. This method may block until the specified number of bytes are skipped or end of stream is reached.

Overrides:

skip in class FilterInputStream

Implementation Note:

This method skips at most Integer.MAX_VALUE bytes.

Parameters:

n - number of bytes to be skipped. If n is zero then no bytes are skipped.

Returns:

the actual number of bytes skipped, which might be zero

Throws:

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

IllegalArgumentException - if n < 0

See Also:

available

public int available() throws IOException

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

Overrides:: available in class FilterInputStream
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

markSupported

public boolean markSupported()

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

Overrides:

markSupported in class FilterInputStream

Returns:

false, always

See Also:

mark

public void mark(int limit)

This operation is not supported.

Overrides:

mark in class FilterInputStream

Parameters:

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

See Also:

reset

public void reset() throws IOException

This operation is not supported.

Overrides:

reset in class FilterInputStream

Throws:

IOException - always thrown

See Also:

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/util/zip/DeflaterInputStream.html