org.apache.commons.compress.archivers.tar
Class TarArchiveInputStream

java.lang.Object
  java.io.InputStream
      org.apache.commons.compress.archivers.ArchiveInputStream
          org.apache.commons.compress.archivers.tar.TarArchiveInputStream

All Implemented Interfaces:

Closeable

public class TarArchiveInputStream
extends ArchiveInputStream

The TarInputStream reads a UNIX tar archive as an InputStream. methods are provided to position at each successive entry in the archive, and the read each entry as a normal input stream using read().

This class is not thread-safe

Field Summary

protected org.apache.commons.compress.archivers.tar.TarBuffer

buffer

Constructor Summary

TarArchiveInputStream(InputStream is)
Constructor for TarInputStream.

TarArchiveInputStream(InputStream is, int blockSize)
Constructor for TarInputStream.

TarArchiveInputStream(InputStream is, int blockSize, int recordSize)
Constructor for TarInputStream.

Method Summary

int	available() Get the available data that can be read from the current entry in the archive.
boolean	canReadEntryData(ArchiveEntry ae) Whether this class is able to read the given entry.
void	close() Closes this stream.
protected TarArchiveEntry	getCurrentEntry()
ArchiveEntry	getNextEntry() Returns the next Archive Entry in this Stream.
TarArchiveEntry	getNextTarEntry() Get the next entry in this tar archive.
int	getRecordSize() Get the record size being used by this stream's TarBuffer.
protected boolean	isAtEOF()
static boolean	matches(byte[] signature, int length) Checks if the signature matches what is expected for a tar file.
int	read(byte[] buf, int offset, int numToRead) Reads bytes from the current tar archive entry.
void	reset() Since we do not support marking just yet, we do nothing.
protected void	setAtEOF(boolean b)
protected void	setCurrentEntry(TarArchiveEntry e)
long	skip(long numToSkip) Skip bytes in the input buffer.

Methods inherited from class org.apache.commons.compress.archivers.ArchiveInputStream

count, count, getBytesRead, getCount, pushedBackBytes, read

Methods inherited from class java.io.InputStream

mark, markSupported, read

Methods inherited from class java.lang.Object

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

Field Detail

buffer

protected final org.apache.commons.compress.archivers.tar.TarBuffer buffer

Constructor Detail

TarArchiveInputStream

public TarArchiveInputStream(InputStream is)

Constructor for TarInputStream.

Parameters:

is - the input stream to use

TarArchiveInputStream

public TarArchiveInputStream(InputStream is,
                             int blockSize)

Constructor for TarInputStream.

Parameters:

is - the input stream to use

blockSize - the block size to use

TarArchiveInputStream

public TarArchiveInputStream(InputStream is,
                             int blockSize,
                             int recordSize)

Constructor for TarInputStream.

Parameters:

is - the input stream to use

blockSize - the block size to use

recordSize - the record size to use

Method Detail

close

public void close()
           throws IOException

Closes this stream. Calls the TarBuffer's close() method.

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException - on error

getRecordSize

public int getRecordSize()

Get the record size being used by this stream's TarBuffer.

Returns:

The TarBuffer record size.

available

public int available()
              throws IOException

Get the available data that can be read from the current entry in the archive. This does not indicate how much data is left in the entire archive, only in the current entry. This value is determined from the entry's size header field and the amount of data already read from the current entry. Integer.MAX_VALUE is returen in case more than Integer.MAX_VALUE bytes are left in the current entry in the archive.

Overrides:

available in class InputStream

Returns:

The number of available bytes for the current entry.

Throws:

IOException - for signature

skip

public long skip(long numToSkip)
          throws IOException

Skip bytes in the input buffer. This skips bytes in the current entry's data, not the entire archive, and will stop at the end of the current entry's data if the number to skip extends beyond that point.

Overrides:

skip in class InputStream

Parameters:

numToSkip - The number of bytes to skip.

Returns:

the number actually skipped

Throws:

IOException - on error

reset

public void reset()

Since we do not support marking just yet, we do nothing.

Overrides:

reset in class InputStream

getNextTarEntry

public TarArchiveEntry getNextTarEntry()
                                throws IOException

Get the next entry in this tar archive. This will skip over any remaining data in the current entry, if there is one, and place the input stream at the header of the next entry, and read the header and instantiate a new TarEntry from the header bytes and return that entry. If there are no more entries in the archive, null will be returned to indicate that the end of the archive has been reached.

Returns:

The next TarEntry in the archive, or null.

Throws:

IOException - on error

getNextEntry

public ArchiveEntry getNextEntry()
                          throws IOException

Description copied from class: ArchiveInputStream

Returns the next Archive Entry in this Stream.

Specified by:

getNextEntry in class ArchiveInputStream

Returns:

the next entry, or null if there are no more entries

Throws:

IOException - if the next entry could not be read

read

public int read(byte[] buf,
                int offset,
                int numToRead)
         throws IOException

Reads bytes from the current tar archive entry. This method is aware of the boundaries of the current entry in the archive and will deal with them as if they were this stream's start and EOF.

Overrides:

read in class InputStream

Parameters:

buf - The buffer into which to place bytes read.

offset - The offset at which to place bytes read.

numToRead - The number of bytes to read.

Returns:

The number of bytes read, or -1 at EOF.

Throws:

IOException - on error

canReadEntryData

public boolean canReadEntryData(ArchiveEntry ae)

Whether this class is able to read the given entry.

May return false if the current entry is a sparse file.

Overrides:

canReadEntryData in class ArchiveInputStream

getCurrentEntry

protected final TarArchiveEntry getCurrentEntry()

setCurrentEntry

protected final void setCurrentEntry(TarArchiveEntry e)

isAtEOF

protected final boolean isAtEOF()

setAtEOF

protected final void setAtEOF(boolean b)

matches

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

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

Parameters:

signature - the bytes to check

length - the number of bytes to check

Returns:

true, if this stream is a tar archive stream, false otherwise