org.apache.tools.tar

Class TarEntry

java.lang.Object

org.apache.tools.tar.TarEntry

All Implemented Interfaces:

TarConstants

public class TarEntry
extends Object
implements TarConstants

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;
  
 

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_DIR_MODE Default permissions bits for directories
static int	DEFAULT_FILE_MODE Default permissions bits for files
static int	MAX_NAMELEN Maximum length of a user's name in the tar file
static int	MILLIS_PER_SECOND Convert millis to seconds

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, MODELEN, MODTIMELEN, NAMELEN, SIZELEN, TMAGIC, UIDLEN, UNAMELEN

Constructor Summary

Constructors

Constructor and Description
TarEntry(byte[] headerBuf) Construct an entry from an archive's header bytes.
TarEntry(File file) Construct an entry for a file.
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.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object it) Determine if the two entries are equal.
boolean	equals(TarEntry it) Determine if the two entries are equal.
int	getCheckSum()
TarEntry[]	getDirectoryEntries() If this entry represents a file, and the file is a directory, return an array of TarEntries for this entry's children.
File	getFile() Get this entry's file.
int	getGroupId() Get this entry's group id.
String	getGroupName() Get this entry's group name.
byte	getLinkFlag()
String	getLinkName() Get this entry's link name.
int	getMode() Get this entry's mode.
Date	getModTime() Set this entry's modification time.
String	getName() Get this entry's name.
long	getSize() Get this entry's file size.
int	getUserId() Get this entry's user id.
String	getUserName() Get this entry's user name.
int	hashCode() Hashcodes are based on entry names.
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
void	parseTarHeader(byte[] header) Parse an entry's header information from a header buffer.
void	setGroupId(int groupId) Set this entry's group id.
void	setGroupName(String groupName) Set this entry's group name.
void	setIds(int userId, int groupId) Convenience method to set this entry's group and user ids.
void	setMode(int mode) Set the mode for this entry
void	setModTime(Date time) Set this entry's modification time.
void	setModTime(long time) Set this entry's modification time.
void	setName(String name) Set this entry's name.
void	setNames(String userName, String groupName) Convenience method to set this entry's group and user names.
void	setSize(long size) Set this entry's file size.
void	setUserId(int userId) Set this entry's user id.
void	setUserName(String userName) Set this entry's user name.
void	writeEntryHeader(byte[] outbuf) Write an entry's header information to a header buffer.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_NAMELEN

public static final int MAX_NAMELEN

Maximum length of a user's name in the tar file

See Also:

Constant Field Values

DEFAULT_DIR_MODE

public static final int DEFAULT_DIR_MODE

Default permissions bits for directories

See Also:

Constant Field Values

DEFAULT_FILE_MODE

public static final int DEFAULT_FILE_MODE

Default permissions bits for files

See Also:

Constant Field Values

MILLIS_PER_SECOND

public static final int MILLIS_PER_SECOND

Convert millis to seconds

See Also:

Constant Field Values

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 entry name

TarEntry

public TarEntry(String name,
        byte linkFlag)

Construct an entry with a name an a link flag.

Parameters:

name - the entry name

linkFlag - the entry link flag.

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[] headerBuf)

Construct an entry from an archive's header bytes. File is set to null.

Parameters:

headerBuf - The header bytes from a tar archive entry.

Method Detail

equals

public boolean equals(TarEntry it)

Determine if the two entries are equal. Equality is determined by the header names being equal.

Parameters:

it - Entry to be checked for equality.

Returns:

True if the entries are equal.

equals

public boolean equals(Object it)

Determine if the two entries are equal. Equality is determined by the header names being equal.

Overrides:

equals in class Object

Parameters:

it - Entry to be checked for equality.

Returns:

True if the entries are equal.

hashCode

public int hashCode()

Hashcodes are based on entry names.

Overrides:

hashCode in class Object

Returns:

the entry hashcode

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 this.

Returns:

True if entry is a descendant of this.

getName

public String getName()

Get this entry's name.

Returns:

This entry's name.

setName

public void setName(String name)

Set this entry's name.

Parameters:

name - This entry's new name.

setMode

public void setMode(int mode)

Set the mode for this entry

Parameters:

mode - the mode for this entry

getLinkName

public String getLinkName()

Get this entry's link name.

Returns:

This entry's link name.

getUserId

public int getUserId()

Get this entry's user id.

Returns:

This entry's user id.

setUserId

public void setUserId(int userId)

Set this entry's user id.

Parameters:

userId - This entry's new user id.

getGroupId

public int getGroupId()

Get this entry's group id.

Returns:

This entry's group id.

setGroupId

public void setGroupId(int groupId)

Set this entry's group id.

Parameters:

groupId - This entry's new group id.

getUserName

public String getUserName()

Get this entry's user name.

Returns:

This entry's user name.

setUserName

public void setUserName(String userName)

Set this entry's user name.

Parameters:

userName - This entry's new user name.

getGroupName

public String getGroupName()

Get this entry's group name.

Returns:

This entry's group name.

setGroupName

public void setGroupName(String groupName)

Set this entry's group name.

Parameters:

groupName - This entry's new group name.

setIds

public void setIds(int userId,
          int groupId)

Convenience method to set this entry's group and user ids.

Parameters:

userId - This entry's new user id.

groupId - This entry's new group id.

setNames

public void setNames(String userName,
            String groupName)

Convenience method to set this entry's group and user names.

Parameters:

userName - This entry's new user name.

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(Date time)

Set this entry's modification time.

Parameters:

time - This entry's new modification time.

getModTime

public Date getModTime()

Set this entry's modification time.

Returns:

time This entry's new modification time.

getFile

public File getFile()

Get this entry's file.

Returns:

This entry's file.

getMode

public int getMode()

Get this entry's mode.

Returns:

This entry's mode.

getSize

public long getSize()

Get this entry's file size.

Returns:

This entry's file size.

setSize

public void setSize(long size)

Set this entry's file size.

Parameters:

size - This entry's new file size.

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

isDirectory

public boolean isDirectory()

Return whether or not this entry represents a directory.

Returns:

True if this entry is a directory.

getLinkFlag

public byte getLinkFlag()

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.

writeEntryHeader

public void writeEntryHeader(byte[] outbuf)

Write an entry's header information to a header buffer.

Parameters:

outbuf - The tar entry header buffer to fill in.

parseTarHeader

public 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.

getCheckSum

public int getCheckSum()