installer
Class TarEntry

java.lang.Object
  extended byinstaller.TarEntry

public class TarEntry
extends 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;
 

See Also:
TarHeader

Field Summary
protected  File file
          If this entry represents a File, this references it.
protected  TarHeader header
          This is the entry's header information.
 
Constructor Summary
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.
 
Method Summary
 void adjustEntryName(byte[] outbuf, String newName)
          Convenience method that will modify an entry's name directly in place in an entry header buffer byte array.
 long computeCheckSum(byte[] buf)
          Compute the checksum of a tar entry header.
 boolean equals(TarEntry it)
          Determine if the two entries are equal.
 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.
 void getFileTarHeader(TarHeader hdr, File file)
          Fill in a TarHeader with information from a File.
 int getGroupId()
          Get this entry's group id.
 String getGroupName()
          Get this entry's group name.
 TarHeader getHeader()
          Get this entry's header.
 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.
 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.
 void nameTarHeader(TarHeader hdr, String name)
          Fill in a TarHeader given only the entry's name.
 void parseTarHeader(TarHeader hdr, byte[] header)
          Parse an entry's TarHeader 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 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, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

file

protected File file
If this entry represents a File, this references it.


header

protected TarHeader header
This is the entry's header information.

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.


TarEntry

public TarEntry(File file)
         throws InvalidHeaderException
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)
         throws InvalidHeaderException
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.

Returns:
it Entry to be checked for equality.

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.

getHeader

public TarHeader getHeader()
Get this entry's header.

Returns:
This entry's TarHeader.

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.

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.


getFile

public File getFile()
Get this entry's file.

Returns:
This entry's file.

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.

adjustEntryName

public void adjustEntryName(byte[] outbuf,
                            String newName)
Convenience method that will modify an entry's name directly in place in an entry header buffer byte array.

Parameters:
outbuf - The buffer containing the entry header to modify.
newName - The new name to place into the header buffer.

isDirectory

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

Returns:
True if this entry is a directory.

getFileTarHeader

public void getFileTarHeader(TarHeader hdr,
                             File file)
                      throws InvalidHeaderException
Fill in a TarHeader with information from a File.

Parameters:
hdr - The TarHeader to fill in.
file - The file from which to get the header information.
Throws:
InvalidHeaderException

getDirectoryEntries

public TarEntry[] getDirectoryEntries()
                               throws InvalidHeaderException
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.
Throws:
InvalidHeaderException

computeCheckSum

public long computeCheckSum(byte[] buf)
Compute the checksum of a tar entry header.

Parameters:
buf - The tar entry's header buffer.
Returns:
The computed checksum.

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(TarHeader hdr,
                           byte[] header)
                    throws InvalidHeaderException
Parse an entry's TarHeader information from a header buffer.

Parameters:
hdr - The TarHeader to fill in from the buffer information.
header - The tar entry header buffer to get information from.
Throws:
InvalidHeaderException

nameTarHeader

public void nameTarHeader(TarHeader hdr,
                          String name)
Fill in a TarHeader given only the entry's name.

Parameters:
hdr - The TarHeader to fill in.
name - The tar entry name.