org.codehaus.plexus.archiver.tar

Class TarEntry

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;
 

Version: $Revision: 2436 $ $Date: 2005-09-01 13:20:41 -0400 (Thu, 01 Sep 2005) $ from org.apache.ant.tools.tar.TarEntry v1.22

Field Summary
intcheckSum
The entry's checksum.
intdevMajor
The entry's major device number.
intdevMinor
The entry's minor device number.
static intDEFAULT_DIR_MODE
Default permissions bits for directories
static intDEFAULT_FILE_MODE
Default permissions bits for files
Filefile
The entry's file reference
intgroupId
The entry's group id.
StringBuffergroupName
The entry's group name.
bytelinkFlag
The entry's link flag.
StringBufferlinkName
The entry's link name.
StringBuffermagic
The entry's magic tag.
intmode
The entry's permission mode.
longmodTime
The entry's modification time.
static intMAX_NAMELEN
Maximum length of a user's name in the tar file
static intMILLIS_PER_SECOND
Convert millis to seconds
StringBuffername
The entry's name.
longsize
The entry's size.
intuserId
The entry's user id.
StringBufferuserName
The entry's user name.
Constructor Summary
TarEntry()
Construct an empty entry and prepares the header values.
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[] headerBuf)
Construct an entry from an archive's header bytes.
Method Summary
booleanequals(TarEntry it)
Determine if the two entries are equal.
booleanequals(Object it)
Determine if the two entries are equal.
intgetChecksum()
Get this entry's checksum time.
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.
StringgetGroupName()
Get this entry's group name.
StringgetLinkName()
Get this entry's link name.
intgetMode()
Get this entry's mode.
DategetModTime()
Get 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.
StringgetUserName()
Get this entry's user name.
inthashCode()
Hashcodes are based on entry names.
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.
voidsetGroupName(String groupName)
Set this entry's group name.
voidsetIds(int userId, int groupId)
Convenience method to set this entry's group and user ids.
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.
voidsetNames(String userName, String groupName)
Convenience method to set this entry's group and user names.
voidsetSize(long size)
Set this entry's file size.
voidsetUserId(int userId)
Set this entry's user id.
voidsetUserName(String userName)
Set this entry's user name.
voidwriteEntryHeader(byte[] outbuf)
Write an entry's header information to a header buffer.

Field Detail

checkSum

private int checkSum
The entry's checksum.

devMajor

private int devMajor
The entry's major device number.

devMinor

private int devMinor
The entry's minor device number.

DEFAULT_DIR_MODE

public static final int DEFAULT_DIR_MODE
Default permissions bits for directories

DEFAULT_FILE_MODE

public static final int DEFAULT_FILE_MODE
Default permissions bits for files

file

private File file
The entry's file reference

groupId

private int groupId
The entry's group id.

groupName

private StringBuffer groupName
The entry's group name.

linkFlag

private byte linkFlag
The entry's link flag.

linkName

private StringBuffer linkName
The entry's link name.

magic

private StringBuffer magic
The entry's magic tag.

mode

private int mode
The entry's permission mode.

modTime

private long modTime
The entry's modification time.

MAX_NAMELEN

public static final int MAX_NAMELEN
Maximum length of a user's name in the tar file

MILLIS_PER_SECOND

public static final int MILLIS_PER_SECOND
Convert millis to seconds

name

private StringBuffer name
The entry's name.

size

private long size
The entry's size.

userId

private int userId
The entry's user id.

userName

private StringBuffer userName
The entry's user name.

Constructor Detail

TarEntry

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

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.

Parameters: it Entry to be checked for equality.

Returns: True if the entries are equal.

getChecksum

public int getChecksum()
Get this entry's checksum time.

Returns: time This entry's new modification time.

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()
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.

getLinkName

public String getLinkName()
Get this entry's link name.

Returns: This entry's link name.

getMode

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

Returns: This entry's mode.

getModTime

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

Returns: time This entry's new modification time.

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()
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.

hashCode

public int hashCode()
Hashcodes are based on entry names.

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.

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

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.

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.

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.

setMode

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

Parameters: mode the mode for this entry

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.

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.

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.

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[] outbuf)
Write an entry's header information to a header buffer.

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