org.apache.commons.compress.archivers.tar

Class TarEntry

public class TarEntry extends Object

This class represents an entry in a Tar archive. It consists of the entry's header, as well as the entry's File. Entries can be instantiated in one of three ways, depending on how they are to be used.

TarEntries that are created from the header bytes read from an archive are instantiated with the TarEntry( byte[] ) constructor. These entries will be used when extracting from or listing the contents of an archive. These entries have their header filled in using the header bytes. They also set the File to null, since they reference an archive entry not a file.

TarEntries that are created from Files that are to be written into an archive are instantiated with the TarEntry( File ) constructor. These entries have their header filled in using the File's information. They also keep a reference to the File for convenience when writing entries.

Finally, TarEntries can be constructed from nothing but a name. This allows the programmer to construct the entry by hand, for instance when only an InputStream is available for writing to the archive, and the header information is constructed from other information. In this case the header fields are set to defaults and the File is set to null.

The C structure for a Tar Entry's header is:

 struct header {
 char name[NAMSIZ];
 char mode[8];
 char uid[8];
 char gid[8];
 char size[12];
 char mtime[12];
 char chksum[8];
 char linkflag;
 char linkname[NAMSIZ];
 char magic[8];
 char uname[TUNMLEN];
 char gname[TGNMLEN];
 char devmajor[8];
 char devminor[8];
 } header;
 

Version: $Revision: 155439 $ $Date: 2007-01-09 10:24:33 +0100 (Tue, 09 Jan 2007) $

Author: Timothy Gerard Endres Stefano Mazzocchi Peter Donald

See Also: TarInputStream TarOutputStream

Field Summary
static intCHKSUMLEN
The length of the checksum field in a header buffer.
static intDEVLEN
The length of the devices field in a header buffer.
static intGIDLEN
The length of the group id field in a header buffer.
static intGNAMELEN
The length of the group name field in a header buffer.
static StringGNU_LONGLINK
The name of the GNU tar entry which contains a long name.
static byteLF_DIR
Directory file type.
static byteLF_GNUTYPE_LONGNAME
Identifies the *next* file on the tape as having a long name.
static byteLF_NORMAL
Normal file type.
intm_checkSum
The entry's modification time.
intm_devMajor
The entry's group name.
intm_devMinor
The entry's major device number.
Filem_file
The entry's minor device number.
intm_groupID
The entry's user id.
StringBufferm_groupName
The entry's user name.
bytem_linkFlag
The entry's checksum.
StringBufferm_linkName
The entry's link flag.
StringBufferm_magic
The entry's link name.
intm_mode
The entry's name.
longm_modTime
The entry's size.
StringBufferm_name
longm_size
The entry's group id.
intm_userID
The entry's permission mode.
StringBufferm_userName
The entry's magic tag.
static intMAGICLEN
The length of the magic field in a header buffer.
static intMODELEN
The length of the mode field in a header buffer.
static intMODTIMELEN
The length of the modification time field in a header buffer.
static intNAMELEN
The length of the name field in a header buffer.
static intSIZELEN
The length of the size field in a header buffer.
static StringTMAGIC
The magic tag representing a POSIX tar archive.
static intUIDLEN
The length of the user id field in a header buffer.
static intUNAMELEN
The length of the user name field in a header buffer.
Constructor Summary
TarEntry(String name)
Construct an entry with only a name.
TarEntry(String name, byte linkFlag)
Construct an entry with a name an a link flag.
TarEntry(File file)
Construct an entry for a file.
TarEntry(byte[] header)
Construct an entry from an archive's header bytes.
TarEntry()
Construct an empty entry and prepares the header values.
Method Summary
booleanequals(TarEntry other)
Determine if the two entries are equal.
intgetCheckSum()
Get this entry's checksum.
TarEntry[]getDirectoryEntries()
If this entry represents a file, and the file is a directory, return an array of TarEntries for this entry's children.
FilegetFile()
Get this entry's file.
intgetGroupId()
Get this entry's group id.
intgetGroupID()
Get this entry's group id.
StringgetGroupName()
Get this entry's group name.
intgetMode()
Get this entry's mode.
DategetModTime()
Set this entry's modification time.
StringgetName()
Get this entry's name.
longgetSize()
Get this entry's file size.
intgetUserId()
Get this entry's user id.
intgetUserID()
Get this entry's user id.
StringgetUserName()
Get this entry's user name.
booleanisDescendent(TarEntry desc)
Determine if the given entry is a descendant of this entry.
booleanisDirectory()
Return whether or not this entry represents a directory.
booleanisGNULongNameEntry()
Indicate if this entry is a GNU long name block
voidparseTarHeader(byte[] header)
Parse an entry's header information from a header buffer.
voidsetGroupId(int groupId)
Set this entry's group id.
voidsetGroupID(int groupId)
Set this entry's group id.
voidsetGroupName(String groupName)
Set this entry's group name.
voidsetMode(int mode)
Set the mode for this entry
voidsetModTime(long time)
Set this entry's modification time.
voidsetModTime(Date time)
Set this entry's modification time.
voidsetName(String name)
Set this entry's name.
voidsetSize(long size)
Set this entry's file size.
voidsetUserId(int userId)
Set this entry's user id.
voidsetUserID(int userId)
Set this entry's user id.
voidsetUserName(String userName)
Set this entry's user name.
voidwriteEntryHeader(byte[] buffer)
Write an entry's header information to a header buffer.

Field Detail

CHKSUMLEN

private static final int CHKSUMLEN
The length of the checksum field in a header buffer.

DEVLEN

private static final int DEVLEN
The length of the devices field in a header buffer.

GIDLEN

private static final int GIDLEN
The length of the group id field in a header buffer.

GNAMELEN

private static final int GNAMELEN
The length of the group name field in a header buffer.

GNU_LONGLINK

static String GNU_LONGLINK
The name of the GNU tar entry which contains a long name.

LF_DIR

private static final byte LF_DIR
Directory file type.

LF_GNUTYPE_LONGNAME

static byte LF_GNUTYPE_LONGNAME
Identifies the *next* file on the tape as having a long name.

LF_NORMAL

private static final byte LF_NORMAL
Normal file type.

m_checkSum

private int m_checkSum
The entry's modification time.

m_devMajor

private int m_devMajor
The entry's group name.

m_devMinor

private int m_devMinor
The entry's major device number.

m_file

private File m_file
The entry's minor device number.

m_groupID

private int m_groupID
The entry's user id.

m_groupName

private StringBuffer m_groupName
The entry's user name.

m_linkFlag

private byte m_linkFlag
The entry's checksum.

m_linkName

private StringBuffer m_linkName
The entry's link flag.

m_magic

private StringBuffer m_magic
The entry's link name.

m_mode

private int m_mode
The entry's name.

m_modTime

private long m_modTime
The entry's size.

m_name

private StringBuffer m_name

m_size

private long m_size
The entry's group id.

m_userID

private int m_userID
The entry's permission mode.

m_userName

private StringBuffer m_userName
The entry's magic tag.

MAGICLEN

private static final int MAGICLEN
The length of the magic field in a header buffer.

MODELEN

private static final int MODELEN
The length of the mode field in a header buffer.

MODTIMELEN

private static final int MODTIMELEN
The length of the modification time field in a header buffer.

NAMELEN

public static final int NAMELEN
The length of the name field in a header buffer.

SIZELEN

private static final int SIZELEN
The length of the size field in a header buffer.

TMAGIC

private static final String TMAGIC
The magic tag representing a POSIX tar archive.

UIDLEN

private static final int UIDLEN
The length of the user id field in a header buffer.

UNAMELEN

private static final int UNAMELEN
The length of the user name field in a header buffer.

Constructor Detail

TarEntry

public TarEntry(String name)
Construct an entry with only a name. This allows the programmer to construct the entry's header "by hand". File is set to null.

Parameters: name the name of the entry

TarEntry

public TarEntry(String name, byte linkFlag)
Construct an entry with a name an a link flag.

Parameters: name Description of Parameter linkFlag Description of Parameter

TarEntry

public TarEntry(File file)
Construct an entry for a file. File is set to file, and the header is constructed from information from the file.

Parameters: file The file that the entry represents.

TarEntry

public TarEntry(byte[] header)
Construct an entry from an archive's header bytes. File is set to null.

Parameters: header The header bytes from a tar archive entry.

TarEntry

private TarEntry()
Construct an empty entry and prepares the header values.

Method Detail

equals

public boolean equals(TarEntry other)
Determine if the two entries are equal. Equality is determined by the header names being equal.

Parameters: other Entry to be checked for equality.

Returns: True if the entries are equal.

getCheckSum

public int getCheckSum()
Get this entry's checksum.

Returns: This entry's checksum.

getDirectoryEntries

public TarEntry[] getDirectoryEntries()
If this entry represents a file, and the file is a directory, return an array of TarEntries for this entry's children.

Returns: An array of TarEntry's for this entry's children.

getFile

public File getFile()
Get this entry's file.

Returns: This entry's file.

getGroupId

public int getGroupId()

Deprecated: Use getGroupID() instead

Get this entry's group id.

Returns: This entry's group id.

See Also: getGroupID

getGroupID

public int getGroupID()
Get this entry's group id.

Returns: This entry's group id.

getGroupName

public String getGroupName()
Get this entry's group name.

Returns: This entry's group name.

getMode

public int getMode()
Get this entry's mode.

Returns: This entry's mode.

getModTime

public Date getModTime()
Set this entry's modification time.

Returns: The ModTime value

getName

public String getName()
Get this entry's name.

Returns: This entry's name.

getSize

public long getSize()
Get this entry's file size.

Returns: This entry's file size.

getUserId

public int getUserId()

Deprecated: Use getUserID() instead

Get this entry's user id.

Returns: This entry's user id.

See Also: getUserID

getUserID

public int getUserID()
Get this entry's user id.

Returns: This entry's user id.

getUserName

public String getUserName()
Get this entry's user name.

Returns: This entry's user name.

isDescendent

public boolean isDescendent(TarEntry desc)
Determine if the given entry is a descendant of this entry. Descendancy is determined by the name of the descendant starting with this entry's name.

Parameters: desc Entry to be checked as a descendent of

Returns: True if entry is a descendant of

isDirectory

public boolean isDirectory()
Return whether or not this entry represents a directory.

Returns: True if this entry is a directory.

isGNULongNameEntry

public boolean isGNULongNameEntry()
Indicate if this entry is a GNU long name block

Returns: true if this is a long name extension provided by GNU tar

parseTarHeader

private void parseTarHeader(byte[] header)
Parse an entry's header information from a header buffer.

Parameters: header The tar entry header buffer to get information from.

setGroupId

public void setGroupId(int groupId)

Deprecated: Use setGroupID() instead

Set this entry's group id.

Parameters: groupId This entry's new group id.

See Also: TarEntry

setGroupID

public void setGroupID(int groupId)
Set this entry's group id.

Parameters: groupId This entry's new group id.

setGroupName

public void setGroupName(String groupName)
Set this entry's group name.

Parameters: groupName This entry's new group name.

setMode

public void setMode(int mode)
Set the mode for this entry

Parameters: mode The new Mode value

setModTime

public void setModTime(long time)
Set this entry's modification time. The parameter passed to this method is in "Java time".

Parameters: time This entry's new modification time.

setModTime

public void setModTime(Date time)
Set this entry's modification time.

Parameters: time This entry's new modification time.

setName

public void setName(String name)
Set this entry's name.

Parameters: name This entry's new name.

setSize

public void setSize(long size)
Set this entry's file size.

Parameters: size This entry's new file size.

setUserId

public void setUserId(int userId)

Deprecated: Use setUserID() instead

Set this entry's user id.

Parameters: userId This entry's new user id.

See Also: TarEntry

setUserID

public void setUserID(int userId)
Set this entry's user id.

Parameters: userId This entry's new user id.

setUserName

public void setUserName(String userName)
Set this entry's user name.

Parameters: userName This entry's new user name.

writeEntryHeader

public void writeEntryHeader(byte[] buffer)
Write an entry's header information to a header buffer.

Parameters: buffer The tar entry header buffer to fill in.