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

java.lang.Object
  extended by org.apache.commons.compress.archivers.tar.TarArchiveEntry
All Implemented Interfaces:
ArchiveEntry, TarConstants
public class TarArchiveEntry
extends Object
implements TarConstants, ArchiveEntry

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[100];     // TarConstants.NAMELEN    - offset   0
 char mode[8];       // TarConstants.MODELEN    - offset 100
 char uid[8];        // TarConstants.UIDLEN     - offset 108
 char gid[8];        // TarConstants.GIDLEN     - offset 116
 char size[12];      // TarConstants.SIZELEN    - offset 124
 char mtime[12];     // TarConstants.MODTIMELEN - offset 136
 char chksum[8];     // TarConstants.CHKSUMLEN  - offset 148
 char linkflag[1];   //                         - offset 156
 char linkname[100]; // TarConstants.NAMELEN    - offset 157
 The following fields are only present in new-style POSIX tar archives:
 char magic[6];      // TarConstants.MAGICLEN   - offset 257
 char version[2];    // TarConstants.VERSIONLEN - offset 263
 char uname[32];     // TarConstants.UNAMELEN   - offset 265
 char gname[32];     // TarConstants.GNAMELEN   - offset 297
 char devmajor[8];   // TarConstants.DEVLEN     - offset 329
 char devminor[8];   // TarConstants.DEVLEN     - offset 337
 char prefix[155];   // TarConstants.PREFIXLEN  - offset 345
 // Used if "name" field is not long enough to hold the path
 char pad[12];       // NULs                    - offset 500
 } header;
 All unused bytes are set to null.
 New-style GNU tar files are slightly different from the above.
 For values of size larger than 077777777777L (11 7s)
 or uid and gid larger than 07777777L (7 7s)
 the sign bit of the first byte is set, and the rest of the
 field is the binary representation of the number.
 See TarUtils.parseOctalOrBinary.

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

 struct oldgnu_header {
 char unused_pad1[345]; // TarConstants.PAD1LEN_GNU       - offset 0
 char atime[12];        // TarConstants.ATIMELEN_GNU      - offset 345
 char ctime[12];        // TarConstants.CTIMELEN_GNU      - offset 357
 char offset[12];       // TarConstants.OFFSETLEN_GNU     - offset 369
 char longnames[4];     // TarConstants.LONGNAMESLEN_GNU  - offset 381
 char unused_pad2;      // TarConstants.PAD2LEN_GNU       - offset 385
 struct sparse sp[4];   // TarConstants.SPARSELEN_GNU     - offset 386
 char isextended;       // TarConstants.ISEXTENDEDLEN_GNU - offset 482
 char realsize[12];     // TarConstants.REALSIZELEN_GNU   - offset 483
 char unused_pad[17];   // TarConstants.PAD3LEN_GNU       - offset 495
 };
Whereas, "struct sparse" is: 
 struct sparse {
 char offset[12];   // offset 0
 char numbytes[12]; // offset 12
 };

Field Summary
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.commons.compress.archivers.tar.TarConstants
ATIMELEN_GNU, CHKSUM_OFFSET, CHKSUMLEN, CTIMELEN_GNU, DEVLEN, FORMAT_OLDGNU, FORMAT_POSIX, GIDLEN, GNAMELEN, GNU_LONGLINK, ISEXTENDEDLEN_GNU, ISEXTENDEDLEN_GNU_SPARSE, LF_BLK, LF_CHR, LF_CONTIG, LF_DIR, LF_FIFO, LF_GNUTYPE_LONGNAME, LF_GNUTYPE_SPARSE, LF_LINK, LF_NORMAL, LF_OLDNORM, LF_PAX_EXTENDED_HEADER_LC, LF_PAX_EXTENDED_HEADER_UC, LF_PAX_GLOBAL_EXTENDED_HEADER, LF_SYMLINK, LONGNAMESLEN_GNU, MAGIC_ANT, MAGIC_GNU, MAGIC_OFFSET, MAGIC_POSIX, MAGICLEN, MAXID, MAXSIZE, MODELEN, MODTIMELEN, NAMELEN, OFFSETLEN_GNU, PAD2LEN_GNU, PREFIXLEN, REALSIZELEN_GNU, SIZELEN, SPARSELEN_GNU, SPARSELEN_GNU_SPARSE, UIDLEN, UNAMELEN, VERSION_ANT, VERSION_GNU_SPACE, VERSION_GNU_ZERO, VERSION_OFFSET, VERSION_POSIX, VERSIONLEN
 
Fields inherited from interface org.apache.commons.compress.archivers.ArchiveEntry
SIZE_UNKNOWN
 
Constructor Summary
TarArchiveEntry(byte[] headerBuf)
          Construct an entry from an archive's header bytes.
TarArchiveEntry(byte[] headerBuf, ZipEncoding encoding)
          Construct an entry from an archive's header bytes.
TarArchiveEntry(File file)
          Construct an entry for a file.
TarArchiveEntry(File file, String fileName)
          Construct an entry for a file.
TarArchiveEntry(String name)
          Construct an entry with only a name.
TarArchiveEntry(String name, boolean preserveLeadingSlashes)
          Construct an entry with only a name.
TarArchiveEntry(String name, byte linkFlag)
          Construct an entry with a name and a link flag.
TarArchiveEntry(String name, byte linkFlag, boolean preserveLeadingSlashes)
          Construct an entry with a name and a link flag.
 
Method Summary
 boolean equals(Object it)
          Determine if the two entries are equal.
 boolean equals(TarArchiveEntry it)
          Determine if the two entries are equal.
 int getDevMajor()
          Get this entry's major device number.
 int getDevMinor()
          Get this entry's minor device number.
 TarArchiveEntry[] 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.
 Date getLastModifiedDate()
          The last modified date of the entry.
 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 getRealSize()
          Get this entry's real file size in case of a sparse file.
 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 isBlockDevice()
          Check if this is a block device entry.
 boolean isCharacterDevice()
          Check if this is a character device entry.
 boolean isCheckSumOK()
          Get this entry's checksum status.
 boolean isDescendent(TarArchiveEntry desc)
          Determine if the given entry is a descendant of this entry.
 boolean isDirectory()
          Return whether or not this entry represents a directory.
 boolean isExtended()
          Indicates in case of a sparse file if an extension sparse header follows.
 boolean isFIFO()
          Check if this is a FIFO (pipe) entry.
 boolean isFile()
          Check if this is a "normal file"
 boolean isGlobalPaxHeader()
          Check if this is a Pax header.
 boolean isGNULongNameEntry()
          Indicate if this entry is a GNU long name block
 boolean isGNUSparse()
          Indicate if this entry is a GNU sparse block
 boolean isLink()
          Check if this is a link entry.
 boolean isPaxHeader()
          Check if this is a Pax header.
 boolean isSymbolicLink()
          Check if this is a symbolic link entry.
 void parseTarHeader(byte[] header)
          Parse an entry's header information from a header buffer.
 void parseTarHeader(byte[] header, ZipEncoding encoding)
          Parse an entry's header information from a header buffer.
 void setDevMajor(int devNo)
          Set this entry's major device number.
 void setDevMinor(int devNo)
          Set this entry's minor device number.
 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 setLinkName(String link)
          Set this entry's link name.
 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.
 void writeEntryHeader(byte[] outbuf, ZipEncoding encoding, boolean starMode)
          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

TarArchiveEntry

public TarArchiveEntry(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

TarArchiveEntry

public TarArchiveEntry(String name,
                       boolean preserveLeadingSlashes)
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
preserveLeadingSlashes - whether to allow leading slashes in the name.
Since:
1.1

TarArchiveEntry

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

Parameters:
name - the entry name
linkFlag - the entry link flag.

TarArchiveEntry

public TarArchiveEntry(String name,
                       byte linkFlag,
                       boolean preserveLeadingSlashes)
Construct an entry with a name and a link flag.

Parameters:
name - the entry name
linkFlag - the entry link flag.
preserveLeadingSlashes - whether to allow leading slashes in the name.
Since:
1.5

TarArchiveEntry

public TarArchiveEntry(File file)
Construct an entry for a file. File is set to file, and the header is constructed from information from the file. The name is set from the normalized file path.

Parameters:
file - The file that the entry represents.

TarArchiveEntry

public TarArchiveEntry(File file,
                       String fileName)
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.
fileName - the name to be used for the entry.

TarArchiveEntry

public TarArchiveEntry(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.
Throws:
IllegalArgumentException - if any of the numeric fields have an invalid format

TarArchiveEntry

public TarArchiveEntry(byte[] headerBuf,
                       ZipEncoding encoding)
                throws IOException
Construct an entry from an archive's header bytes. File is set to null.

Parameters:
headerBuf - The header bytes from a tar archive entry.
encoding - encoding to use for file names
Throws:
IllegalArgumentException - if any of the numeric fields have an invalid format
IOException
Since:
Commons Compress 1.4
Method Detail

equals

public boolean equals(TarArchiveEntry 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(TarArchiveEntry 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.

Specified by:
getName in interface ArchiveEntry
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.

setLinkName

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

Parameters:
link - the link name to use.
Since:
1.1

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.

getLastModifiedDate

public Date getLastModifiedDate()
The last modified date of the entry.

Specified by:
getLastModifiedDate in interface ArchiveEntry

isCheckSumOK

public boolean isCheckSumOK()
Get this entry's checksum status.

Returns:
if the header checksum is reasonably correct
Since:
1.5
See Also:
TarUtils.verifyCheckSum(byte[])

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.

Specified by:
getSize in interface ArchiveEntry
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.
Throws:
IllegalArgumentException - if the size is < 0.

getDevMajor

public int getDevMajor()
Get this entry's major device number.

Returns:
This entry's major device number.
Since:
1.4

setDevMajor

public void setDevMajor(int devNo)
Set this entry's major device number.

Parameters:
devNo - This entry's major device number.
Throws:
IllegalArgumentException - if the devNo is < 0.
Since:
1.4

getDevMinor

public int getDevMinor()
Get this entry's minor device number.

Returns:
This entry's minor device number.
Since:
1.4

setDevMinor

public void setDevMinor(int devNo)
Set this entry's minor device number.

Parameters:
devNo - This entry's minor device number.
Throws:
IllegalArgumentException - if the devNo is < 0.
Since:
1.4

isExtended

public boolean isExtended()
Indicates in case of a sparse file if an extension sparse header follows.

Returns:
true if an extension sparse header follows.

getRealSize

public long getRealSize()
Get this entry's real file size in case of a sparse file.

Returns:
This entry's real file size.

isGNUSparse

public boolean isGNUSparse()
Indicate if this entry is a GNU sparse block

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

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

isPaxHeader

public boolean isPaxHeader()
Check if this is a Pax header.

Returns:
true if this is a Pax header.
Since:
1.1

isGlobalPaxHeader

public boolean isGlobalPaxHeader()
Check if this is a Pax header.

Returns:
true if this is a Pax header.
Since:
1.1

isDirectory

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

Specified by:
isDirectory in interface ArchiveEntry
Returns:
True if this entry is a directory.

isFile

public boolean isFile()
Check if this is a "normal file"

Since:
1.2

isSymbolicLink

public boolean isSymbolicLink()
Check if this is a symbolic link entry.

Since:
1.2

isLink

public boolean isLink()
Check if this is a link entry.

Since:
1.2

isCharacterDevice

public boolean isCharacterDevice()
Check if this is a character device entry.

Since:
1.2

isBlockDevice

public boolean isBlockDevice()
Check if this is a block device entry.

Since:
1.2

isFIFO

public boolean isFIFO()
Check if this is a FIFO (pipe) entry.

Since:
1.2

getDirectoryEntries

public TarArchiveEntry[] 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.

This method does not use the star/GNU tar/BSD tar extensions.

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

writeEntryHeader

public void writeEntryHeader(byte[] outbuf,
                             ZipEncoding encoding,
                             boolean starMode)
                      throws IOException
Write an entry's header information to a header buffer.

Parameters:
outbuf - The tar entry header buffer to fill in.
encoding - encoding to use when writing the file name.
starMode - whether to use the star/GNU tar/BSD tar extension for numeric fields if their value doesn't fit in the maximum size of standard tar archives
Throws:
IOException
Since:
1.4

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.
Throws:
IllegalArgumentException - if any of the numeric fields have an invalid format

parseTarHeader

public void parseTarHeader(byte[] header,
                           ZipEncoding encoding)
                    throws IOException
Parse an entry's header information from a header buffer.

Parameters:
header - The tar entry header buffer to get information from.
encoding - encoding to use for file names
Throws:
IllegalArgumentException - if any of the numeric fields have an invalid format
IOException
Since:
Commons Compress 1.4
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