Package org.jline.reader

Interface Buffer

All Known Implementing Classes:

BufferImpl

public interface Buffer

Represents the editable text buffer in the LineReader.

The Buffer interface provides methods for manipulating the text that the user is currently editing in the LineReader. It supports operations such as cursor movement, text insertion and deletion, and content retrieval.

The buffer maintains a current cursor position that indicates where text will be inserted or deleted. Many of the methods in this interface operate relative to this cursor position.

The default implementation is BufferImpl.

See Also:

• LineReader.getBuffer()
• BufferImpl

Method Summary

Modifier and Type	Method	Description
int	atChar(int i)	Returns the character at the specified position in the buffer.
boolean	backspace()	Deletes the character before the cursor position.
int	backspace(int num)	Deletes multiple characters before the cursor position.
boolean	clear()	Clears the buffer content.
Buffer	copy()	Creates a copy of this buffer.
void	copyFrom(Buffer buffer)	Copies the content and cursor position from another buffer.
int	currChar()	Returns the character at the current cursor position.
boolean	currChar(int c)	Replaces the character at the current cursor position.
int	cursor()	Returns the current cursor position in the buffer.
boolean	cursor(int position)	Moves the cursor to the specified position.
boolean	delete()	Deletes the character at the cursor position.
int	delete(int num)	Deletes multiple characters starting at the cursor position.
boolean	down()	Moves the cursor down one line while maintaining the same column position if possible.
int	length()	Returns the length of the buffer.
int	move(int num)	Moves the cursor by the specified number of characters.
boolean	moveXY(int dx, int dy)	Moves the cursor by the specified number of columns and rows.
int	nextChar()	Returns the character after the current cursor position.
int	prevChar()	Returns the character before the current cursor position.
String	substring(int start)	Returns a substring of the buffer from the specified start position to the end.
String	substring(int start, int end)	Returns a substring of the buffer from the specified start position to the specified end position.
String	toString()
boolean	up()	Moves the cursor up one line while maintaining the same column position if possible.
String	upToCursor()	Returns a substring of the buffer from the beginning to the current cursor position.
void	write(int c)	Writes a character at the current cursor position and advances the cursor.
void	write(int c, boolean overTyping)	Writes a character at the current cursor position and advances the cursor.
void	write(CharSequence str)	Writes a string at the current cursor position and advances the cursor.
void	write(CharSequence str, boolean overTyping)	Writes a string at the current cursor position and advances the cursor.
void	zeroOut()	Clear any internal buffer.

Method Details

cursor

int cursor()

Returns the current cursor position in the buffer.

Returns:

the current cursor position (0-based index)

atChar

int atChar(int i)

Returns the character at the specified position in the buffer.

Parameters:

i - the position to check

Returns:

the character at the specified position, or -1 if the position is invalid

length

int length()

Returns the length of the buffer.

Returns:

the number of characters in the buffer

currChar

int currChar()

Returns the character at the current cursor position.

Returns:

the character at the cursor position, or -1 if the cursor is at the end of the buffer

prevChar

int prevChar()

Returns the character before the current cursor position.

Returns:

the character before the cursor position, or -1 if the cursor is at the beginning of the buffer

nextChar

int nextChar()

Returns the character after the current cursor position.

Returns:

the character after the cursor position, or -1 if the cursor is at the end of the buffer

cursor

boolean cursor(int position)

Moves the cursor to the specified position.

Parameters:

position - the position to move the cursor to

Returns:

true if the cursor was moved, false if the position was invalid

move

int move(int num)

Moves the cursor by the specified number of characters. Positive values move right, negative values move left.

Parameters:

num - the number of characters to move

Returns:

the number of positions actually moved

up

boolean up()

Moves the cursor up one line while maintaining the same column position if possible. This is used for multi-line editing.

Returns:

true if the cursor was moved, false if it was already at the first line

down

boolean down()

Moves the cursor down one line while maintaining the same column position if possible. This is used for multi-line editing.

Returns:

true if the cursor was moved, false if it was already at the last line

moveXY

boolean moveXY(int dx,
 int dy)

Moves the cursor by the specified number of columns and rows. This is used for multi-line editing.

Parameters:

dx - the number of columns to move (positive for right, negative for left)

dy - the number of rows to move (positive for down, negative for up)

Returns:

true if the cursor was moved, false otherwise

clear

boolean clear()

Clears the buffer content.

Returns:

true if the buffer was modified

currChar

boolean currChar(int c)

Replaces the character at the current cursor position.

Parameters:

c - the character to set at the current position

Returns:

true if the buffer was modified

write

void write(int c)

Writes a character at the current cursor position and advances the cursor.

Parameters:

c - the character to write

write

void write(int c,
 boolean overTyping)

Writes a character at the current cursor position and advances the cursor.

Parameters:

c - the character to write

overTyping - if true, overwrites the character at the current position

write

void write(CharSequence str)

Writes a string at the current cursor position and advances the cursor.

Parameters:

str - the string to write

write

void write(CharSequence str,
 boolean overTyping)

Writes a string at the current cursor position and advances the cursor.

Parameters:

str - the string to write

overTyping - if true, overwrites characters at the current position

backspace

boolean backspace()

Deletes the character before the cursor position.

Returns:

true if the buffer was modified

backspace

int backspace(int num)

Deletes multiple characters before the cursor position.

Parameters:

num - the number of characters to delete

Returns:

the number of characters actually deleted

delete

boolean delete()

Deletes the character at the cursor position.

Returns:

true if the buffer was modified

delete

int delete(int num)

Deletes multiple characters starting at the cursor position.

Parameters:

num - the number of characters to delete

Returns:

the number of characters actually deleted

substring

String substring(int start)

Returns a substring of the buffer from the specified start position to the end.

Parameters:

start - the start index, inclusive

Returns:

the substring

substring

String substring(int start,
 int end)

Returns a substring of the buffer from the specified start position to the specified end position.

Parameters:

start - the start index, inclusive

end - the end index, exclusive

Returns:

the substring

upToCursor

String upToCursor()

Returns a substring of the buffer from the beginning to the current cursor position.

Returns:

the substring

toString

String toString()

Overrides:

toString in class Object

copy

Buffer copy()

Creates a copy of this buffer.

Returns:

a new buffer with the same content and cursor position

copyFrom

void copyFrom(Buffer buffer)

Copies the content and cursor position from another buffer.

Parameters:

buffer - the buffer to copy from

zeroOut

void zeroOut()

Clear any internal buffer.