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

java.lang.Object
  extended by org.apache.commons.compress.archivers.tar.TarEntry

public class TarEntry
extends java.lang.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
private static int CHKSUMLEN
          The length of the checksum field in a header buffer.
private static int DEVLEN
          The length of the devices field in a header buffer.
private static int GIDLEN
          The length of the group id field in a header buffer.
private static int GNAMELEN
          The length of the group name field in a header buffer.
(package private) static java.lang.String GNU_LONGLINK
          The name of the GNU tar entry which contains a long name.
private static byte LF_DIR
          Directory file type.
(package private) static byte LF_GNUTYPE_LONGNAME
          Identifies the *next* file on the tape as having a long name.
private static byte LF_NORMAL
          Normal file type.
private  int m_checkSum
          The entry's modification time.
private  int m_devMajor
          The entry's group name.
private  int m_devMinor
          The entry's major device number.
private  java.io.File m_file
          The entry's minor device number.
private  int m_groupID
          The entry's user id.
private  java.lang.StringBuffer m_groupName
          The entry's user name.
private  byte m_linkFlag
          The entry's checksum.
private  java.lang.StringBuffer m_linkName
          The entry's link flag.
private  java.lang.StringBuffer m_magic
          The entry's link name.
private  int m_mode
          The entry's name.
private  long m_modTime
          The entry's size.
private  java.lang.StringBuffer m_name
           
private  long m_size
          The entry's group id.
private  int m_userID
          The entry's permission mode.
private  java.lang.StringBuffer m_userName
          The entry's magic tag.
private static int MAGICLEN
          The length of the magic field in a header buffer.
private static int MODELEN
          The length of the mode field in a header buffer.
private static int MODTIMELEN
          The length of the modification time field in a header buffer.
static int NAMELEN
          The length of the name field in a header buffer.
private static int SIZELEN
          The length of the size field in a header buffer.
private static java.lang.String TMAGIC
          The magic tag representing a POSIX tar archive.
private static int UIDLEN
          The length of the user id field in a header buffer.
private static int UNAMELEN
          The length of the user name field in a header buffer.
 
Constructor Summary
private TarEntry()
          Construct an empty entry and prepares the header values.
  TarEntry(byte[] header)
          Construct an entry from an archive's header bytes.
  TarEntry(java.io.File file)
          Construct an entry for a file.
  TarEntry(java.lang.String name)
          Construct an entry with only a name.
  TarEntry(java.lang.String name, byte linkFlag)
          Construct an entry with a name an a link flag.
 
Method Summary
 boolean equals(TarEntry other)
          Determine if the two entries are equal.
 int getCheckSum()
          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.
 java.io.File getFile()
          Get this entry's file.
 int getGroupId()
          Deprecated. Use getGroupID() instead
 int getGroupID()
          Get this entry's group id.
 java.lang.String getGroupName()
          Get this entry's group name.
 int getMode()
          Get this entry's mode.
 java.util.Date getModTime()
          Set this entry's modification time.
 java.lang.String getName()
          Get this entry's name.
 long getSize()
          Get this entry's file size.
 int getUserId()
          Deprecated. Use getUserID() instead
 int getUserID()
          Get this entry's user id.
 java.lang.String getUserName()
          Get this entry's user name.
 boolean isDescendent(TarEntry desc)
          Determine if the given entry is a descendant of this entry.
 boolean isDirectory()
          Return whether or not this entry represents a directory.
 boolean isGNULongNameEntry()
          Indicate if this entry is a GNU long name block
private  void parseTarHeader(byte[] header)
          Parse an entry's header information from a header buffer.
 void setGroupId(int groupId)
          Deprecated. Use setGroupID() instead
 void setGroupID(int groupId)
          Set this entry's group id.
 void setGroupName(java.lang.String groupName)
          Set this entry's group name.
 void setMode(int mode)
          Set the mode for this entry
 void setModTime(java.util.Date time)
          Set this entry's modification time.
 void setModTime(long time)
          Set this entry's modification time.
 void setName(java.lang.String name)
          Set this entry's name.
 void setSize(long size)
          Set this entry's file size.
 void setUserId(int userId)
          Deprecated. Use setUserID() instead
 void setUserID(int userId)
          Set this entry's user id.
 void setUserName(java.lang.String userName)
          Set this entry's user name.
 void writeEntryHeader(byte[] buffer)
          Write an entry's header information to a header buffer.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

MODELEN

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

See Also:
Constant Field Values

UIDLEN

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

See Also:
Constant Field Values

GIDLEN

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

See Also:
Constant Field Values

CHKSUMLEN

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

See Also:
Constant Field Values

SIZELEN

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

See Also:
Constant Field Values

MAGICLEN

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

See Also:
Constant Field Values

MODTIMELEN

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

See Also:
Constant Field Values

UNAMELEN

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

See Also:
Constant Field Values

GNAMELEN

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

See Also:
Constant Field Values

DEVLEN

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

See Also:
Constant Field Values

LF_NORMAL

private static final byte LF_NORMAL
Normal file type.

See Also:
Constant Field Values

LF_DIR

private static final byte LF_DIR
Directory file type.

See Also:
Constant Field Values

TMAGIC

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

See Also:
Constant Field Values

GNU_LONGLINK

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


LF_GNUTYPE_LONGNAME

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


NAMELEN

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

See Also:
Constant Field Values

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 java.io.File m_file
The entry's minor device number.


m_groupID

private int m_groupID
The entry's user id.


m_groupName

private java.lang.StringBuffer m_groupName
The entry's user name.


m_linkFlag

private byte m_linkFlag
The entry's checksum.


m_linkName

private java.lang.StringBuffer m_linkName
The entry's link flag.


m_magic

private java.lang.StringBuffer m_magic
The entry's link name.


m_modTime

private long m_modTime
The entry's size.


m_mode

private int m_mode
The entry's name.


m_name

private java.lang.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 java.lang.StringBuffer m_userName
The entry's magic tag.

Constructor Detail

TarEntry

public TarEntry(java.lang.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(java.lang.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(java.io.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

setGroupID

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

Parameters:
groupId - This entry's new group id.

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:
setGroupID(int)

setGroupName

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

Parameters:
groupName - This entry's new group name.

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(java.util.Date time)
Set this entry's modification time.

Parameters:
time - This entry's new modification time.

setMode

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

Parameters:
mode - The new Mode value

setName

public void setName(java.lang.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)
Set this entry's user id.

Parameters:
userId - This entry's new user id.

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:
setUserID(int)

setUserName

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

Parameters:
userName - This entry's new user name.

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 java.io.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 java.lang.String getGroupName()
Get this entry's group name.

Returns:
This entry's group name.

getModTime

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

Returns:
The ModTime value

getMode

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

Returns:
This entry's mode.

getName

public java.lang.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.

getCheckSum

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

Returns:
This entry's checksum.

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 java.lang.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

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.

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.

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.