org.apache.commons.compress.compressors.gzip

Class GzipCompressorInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.compress.compressors.CompressorInputStream

org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class GzipCompressorInputStream
extends CompressorInputStream

Input stream that decompresses .gz files. This supports decompressing concatenated .gz files which is important when decompressing standalone .gz files.

GZIPInputStream doesn't decompress concatenated .gz files: it stops after the first member and silently ignores the rest. It doesn't leave the read position to point to the beginning of the next member, which makes it difficult workaround the lack of concatenation support.

Instead of using GZIPInputStream, this class has its own .gz container format decoder. The actual decompression is done with Inflater.

Constructor Summary

Constructors

Constructor and Description
GzipCompressorInputStream(InputStream inputStream) Constructs a new input stream that decompresses gzip-compressed data from the specified input stream.
GzipCompressorInputStream(InputStream inputStream, boolean decompressConcatenated) Constructs a new input stream that decompresses gzip-compressed data from the specified input stream.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the input stream (unless it is System.in).
GzipParameters	getMetaData() Provides the stream's meta data - may change with each stream when decompressing concatenated streams.
static boolean	matches(byte[] signature, int length) Checks if the signature matches what is expected for a .gz file.
int	read()
int	read(byte[] b, int off, int len)

Methods inherited from class org.apache.commons.compress.compressors.CompressorInputStream

count, count, getBytesRead, getCount, pushedBackBytes

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

GzipCompressorInputStream

public GzipCompressorInputStream(InputStream inputStream)
                          throws IOException

Constructs a new input stream that decompresses gzip-compressed data from the specified input stream.

This is equivalent to GzipCompressorInputStream(inputStream, false) and thus will not decompress concatenated .gz files.

Parameters:

inputStream - the InputStream from which this object should be created of

Throws:

IOException - if the stream could not be created

GzipCompressorInputStream

public GzipCompressorInputStream(InputStream inputStream,
                                 boolean decompressConcatenated)
                          throws IOException

Constructs a new input stream that decompresses gzip-compressed data from the specified input stream.

If decompressConcatenated is false: This decompressor might read more input than it will actually use. If inputStream supports mark and reset, then the input position will be adjusted so that it is right after the last byte of the compressed stream. If mark isn't supported, the input position will be undefined.

Parameters:

inputStream - the InputStream from which this object should be created of

decompressConcatenated - if true, decompress until the end of the input; if false, stop after the first .gz member

Throws:

IOException - if the stream could not be created

Method Detail

getMetaData

public GzipParameters getMetaData()

Provides the stream's meta data - may change with each stream when decompressing concatenated streams.

Returns:

the stream's meta data

Since:

1.8

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

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

Overrides:

read in class InputStream

Throws:

IOException

Since:

1.1

matches

public static boolean matches(byte[] signature,
                              int length)

Checks if the signature matches what is expected for a .gz file.

Parameters:

signature - the bytes to check

length - the number of bytes to check

Returns:

true if this is a .gz stream, false otherwise

Since:

1.1

close

public void close()
           throws IOException

Closes the input stream (unless it is System.in).

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

Since:

1.2