Package 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;
 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 Details

    • MAX_NAMELEN

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

    • DEFAULT_DIR_MODE

      public static final int DEFAULT_DIR_MODE
      Default permissions bits for directories
      See Also:

    • DEFAULT_FILE_MODE

      public static final int DEFAULT_FILE_MODE
      Default permissions bits for files
      See Also:

    • MILLIS_PER_SECOND

      public static final int MILLIS_PER_SECOND
      Convert millis to seconds
      See Also:

  • Constructor Details

    • 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, 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.

    • TarEntry

      public TarEntry(String name, byte linkFlag)
      Construct an entry with a name and 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. The name is set from the normalized file path.
      Parameters:
      file - The file that the entry represents.

    • TarEntry

      public TarEntry(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.

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

    • TarEntry

      public TarEntry(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 - if an error occurs during reading the archive

  • Method Details

    • 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 descendant 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

    • getLinkFlag

      public byte getLinkFlag()
      Get this entry's link flag.
      Returns:
      This entry's link flag.
      Since:
      1.10.12

    • setLinkFlag

      public void setLinkFlag(byte linkFlag)
      Set this entry's link flag.
      Parameters:
      link - the link flag to use.
      Since:
      1.10.12

    • 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.

    • getUserId

      @Deprecated public int getUserId()
      Deprecated.
      use #getLongUserId instead as user ids can be bigger than Integer.MAX_VALUE
      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.

    • getLongUserId

      public long getLongUserId()
      Get this entry's user id.
      Returns:
      This entry's user id.
      Since:
      1.9.5

    • setUserId

      public void setUserId(long userId)
      Set this entry's user id.
      Parameters:
      userId - This entry's new user id.
      Since:
      1.9.5

    • getGroupId

      @Deprecated public int getGroupId()
      Deprecated.
      use #getLongGroupId instead as group ids can be bigger than Integer.MAX_VALUE
      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.

    • getLongGroupId

      public long getLongGroupId()
      Get this entry's group id.
      Returns:
      This entry's group id.
      Since:
      1.9.5

    • setGroupId

      public void setGroupId(long groupId)
      Set this entry's group id.
      Parameters:
      groupId - This entry's new group id.
      Since:
      1.9.5

    • 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.
      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.

    • 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.

    • getDevMinor

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

    • 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.

    • 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

    • isGNULongLinkEntry

      public boolean isGNULongLinkEntry()
      Indicate if this entry is a GNU long linkname block
      Returns:
      true if this is a long name 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.

    • isGlobalPaxHeader

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

    • isDirectory

      public boolean isDirectory()
      Return whether or not this entry represents a directory.
      Returns:
      True if this entry is a directory.

    • isFile

      public boolean isFile()
      Check if this is a "normal file".
      Returns:
      true if it is a 'normal' file

    • isSymbolicLink

      public boolean isSymbolicLink()
      Check if this is a symbolic link entry.
      Returns:
      true if it is a symlink

    • isLink

      public boolean isLink()
      Check if this is a link entry.
      Returns:
      true if it is a link

    • isCharacterDevice

      public boolean isCharacterDevice()
      Check if this is a character device entry.
      Returns:
      true if it is a character device entry

    • isBlockDevice

      public boolean isBlockDevice()
      Returns:
      true if this is a block device entry.

    • isFIFO

      public boolean isFIFO()
      Returns:
      true if this is a FIFO (pipe) entry.

    • 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.

      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 - if an error occurs while writing the archive

    • 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 - if an error occurs while reading the archive