de.schlichtherle.io.archive.tar
Class TarInputArchive

java.lang.Object
  de.schlichtherle.io.archive.tar.TarInputArchive

All Implemented Interfaces:

InputArchive, org.apache.tools.tar.TarConstants

public class TarInputArchive
extends Object
implements InputArchive, org.apache.tools.tar.TarConstants

Presents a TarInputStream as a randomly accessible archive.

Warning: The constructor of this class extracts each entry in the archive to a temporary file. This may be very time and space consuming for large archives, but is the fastest implementation for subsequent random access, since there is no way the archive driver could predict the client application's behaviour.

Since:

TrueZIP 6.0

Version:

$Id: TarInputArchive.java,v 1.4 2010/08/20 13:09:44 christian_schlichtherle Exp $

Author:

Christian Schlichtherle

Field Summary

Fields inherited from interface org.apache.tools.tar.TarConstants

CHKSUMLEN, DEVLEN, GIDLEN, GNAMELEN, GNU_LONGLINK, GNU_TMAGIC, LF_BLK, LF_CHR, LF_CONTIG, LF_DIR, LF_FIFO, LF_GNUTYPE_LONGNAME, LF_LINK, LF_NORMAL, LF_OLDNORM, LF_SYMLINK, MAGICLEN, MAXSIZE, MODELEN, MODTIMELEN, NAMELEN, SIZELEN, TMAGIC, UIDLEN, UNAMELEN

Constructor Summary

TarInputArchive(InputStream in)
Extracts the entire TAR input stream into a temporary directory in order to allow subsequent random access to its entries.

Method Summary

void	close() Closes this input archive and releases any system resources associated with it.
Enumeration	getArchiveEntries() Returns an enumeration of the ArchiveEntry instances in this archive.
ArchiveEntry	getArchiveEntry(String entryName) Returns the ArchiveEntry for the given entry name or null if no entry with this name exists.
InputStream	getInputStream(ArchiveEntry entry, ArchiveEntry dstEntry) Returns a new InputStream for reading the contents of the given archive entry.
InputArchiveMetaData	getMetaData() Returns the meta data for this input archive.
int	getNumArchiveEntries() Returns the number of ArchiveEntry instances in this archive.
void	setMetaData(InputArchiveMetaData metaData) Sets the meta data for this input archive.

Methods inherited from class java.lang.Object

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

Constructor Detail

TarInputArchive

public TarInputArchive(InputStream in)
                throws IOException

Extracts the entire TAR input stream into a temporary directory in order to allow subsequent random access to its entries.

Parameters:

in - The input stream from which this input archive file should be initialized. This stream is not used by any of the methods in this class after the constructor has terminated and is never closed! So it is safe and recommended to close it upon termination of this constructor.

Throws:

IOException

Method Detail

getNumArchiveEntries

public int getNumArchiveEntries()

Description copied from interface: InputArchive

Returns the number of ArchiveEntry instances in this archive.

Specified by:

getNumArchiveEntries in interface InputArchive

getArchiveEntries

public Enumeration getArchiveEntries()

Description copied from interface: InputArchive

Returns an enumeration of the ArchiveEntry instances in this archive.

Specified by:

getArchiveEntries in interface InputArchive

getArchiveEntry

public ArchiveEntry getArchiveEntry(String entryName)

Description copied from interface: InputArchive

Returns the ArchiveEntry for the given entry name or null if no entry with this name exists.

Specified by:

getArchiveEntry in interface InputArchive

Parameters:

entryName - A valid archive entry name - never null.

See Also:

Requirements for Archive Entry Names

getInputStream

public InputStream getInputStream(ArchiveEntry entry,
                                  ArchiveEntry dstEntry)
                           throws IOException

Description copied from interface: InputArchive

Returns a new InputStream for reading the contents of the given archive entry.

The returned stream should preferrably be unbuffered, as buffering is usually done in higher layers (all copy routines in TrueZIP do this and most client applications do it, too). Buffering twice does not increase, but decrease performance.

Note that the stream is guaranteed to be closed before the InputArchive.close() method of this archive is called!

Specified by:

getInputStream in interface InputArchive

Parameters:

entry - A valid reference to an archive entry. The runtime class of this entry is the same as the runtime class of the entries returned by InputArchive.getArchiveEntries().

dstEntry - If not null, this identifies the entry to which TrueZIP is actually copying data to and should be used to implement the Direct Data Copying (DDC) feature. Note that there is no guarantee on the runtime type of this object; it may have been created by other drivers.

For example, the ZIP driver family uses this to determine if data should be provided in its deflated form if the destination entry is another ZIP file entry.

Returns:

A (preferrably unbuffered) InputStream to read the archive entry data from. null is not allowed!

Throws:

InputArchiveBusyException - If the archive is currently busy on input for another entry. This exception is guaranteed to be recoverable, meaning it should be possible to read the same entry again as soon as the archive is not busy on input anymore.

FileNotFoundException - If the archive entry does not exist or is not accessible for some reason.

IOException - On any other exceptional condition.

close

public void close()
           throws IOException

Description copied from interface: InputArchive

Closes this input archive and releases any system resources associated with it.

Specified by:

close in interface InputArchive

Throws:

IOException - On any I/O related issue.

getMetaData

public InputArchiveMetaData getMetaData()

Description copied from interface: InputArchive

Returns the meta data for this input archive. The default value is null.

Specified by:

getMetaData in interface InputArchive

setMetaData

public void setMetaData(InputArchiveMetaData metaData)

Description copied from interface: InputArchive

Sets the meta data for this input archive.

Specified by:

setMetaData in interface InputArchive

Parameters:

metaData - The meta data - may not be null.