com.nothome.delta.text
Class GDiffTextWriter

java.lang.Object
  com.nothome.delta.text.GDiffTextWriter

All Implemented Interfaces:

DiffTextWriter, Closeable

public class GDiffTextWriter
extends Object
implements DiffTextWriter

A text-file format analog for GDIFF, which is only supported for binary streams. The output follows the following extended BNF format:

 gdiff-text ::= header , { copy | data }
 header ::= 'gdt' , { version } , '\n'
 copy   ::= 'y' offset ',' length '\n'
 data   ::= 'i' length '\n' text-chunk '\n'
 length ::= hex-digit , { hex-digit }
 offset ::= hex-digit , { hex-digit }
 hex-digit  ::= '0'-'9' | 'a'-'f'
 text-chunk ::= (* arbitrary text string *)
 version ::= '1'-'9'
 

Note that 'y' is used for copy and 'i' for data since they aren't to be confused with the hex characters 'c' and 'd'.

Note that the length of text-string is capped at CHUNK_SIZE characters for this implementation.

The initial version is 1 and is optionally indicated. Newer versions may support additional commands and hints.

See also: http://www.w3.org/TR/NOTE-gdiff-19970901.html.

Field Summary

static int	CHUNK_SIZE Max length of a "text-chunk".
static char	COMMA Comma delimiter.
static char	COPY Copy command character.
static char	DATA Data command character.
static char	LF Line feed character.

Constructor Summary

GDiffTextWriter(Writer w)
Constructs a new GDiffTextWriter.

Method Summary

void	addCopy(int offset, int length) Add a copy command.
void	addData(char c) Add a character to output.
void	close() Frees internal resources; closes output stream.
void	flush() Writes current state to output stream.

Methods inherited from class java.lang.Object

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

Field Detail

LF

public static final char LF

Line feed character.

See Also:

Constant Field Values

COPY

public static final char COPY

Copy command character.

See Also:

Constant Field Values

DATA

public static final char DATA

Data command character.

See Also:

Constant Field Values

COMMA

public static final char COMMA

Comma delimiter.

See Also:

Constant Field Values

CHUNK_SIZE

public static final int CHUNK_SIZE

Max length of a "text-chunk". Although this could be arbitrarily large, this caps the buffer size, facilitating reading.

See Also:

Constant Field Values

Constructor Detail

GDiffTextWriter

public GDiffTextWriter(Writer w)
                throws IOException

Constructs a new GDiffTextWriter.

Parameters:

w -

Throws:

IOException

Method Detail

addCopy

public void addCopy(int offset,
                    int length)
             throws IOException

Description copied from interface: DiffTextWriter

Add a copy command.

Specified by:

addCopy in interface DiffTextWriter

Parameters:

offset - start of sequence

length - length of sequence

Throws:

IOException

addData

public void addData(char c)
             throws IOException

Description copied from interface: DiffTextWriter

Add a character to output.

Specified by:

addData in interface DiffTextWriter

Throws:

IOException

flush

public void flush()
           throws IOException

Description copied from interface: DiffTextWriter

Writes current state to output stream.

Specified by:

flush in interface DiffTextWriter

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: DiffTextWriter

Frees internal resources; closes output stream.

Specified by:

close in interface DiffTextWriter

Specified by:

close in interface Closeable

Throws:

IOException