java.lang.Object
- org.jline.reader.impl.BufferImpl

All Implemented Interfaces:

Buffer
```
public class BufferImpl
extends java.lang.Object
implements Buffer
```
Default implementation of the Buffer interface.
This class provides a mutable buffer for storing and manipulating the text being edited in the LineReader. It maintains the text content and the current cursor position, and provides methods for text insertion, deletion, and cursor movement.
Key features include:
- Efficient text insertion and deletion with a gap buffer implementation
- Support for Unicode characters beyond the Basic Multilingual Plane
- Cursor movement in both character and line coordinates
- Copy and paste operations
- Secure clearing of buffer contents
The buffer uses a gap buffer data structure for efficient editing operations, which provides good performance for the typical editing patterns in a line editor.
Since:

2.0

See Also:

Buffer, LineReader.getBuffer()

Constructor Summary

Constructors
Constructor Description

BufferImpl()
Creates a new buffer with the default size (64).

BufferImpl(int size)
Creates a new buffer with the specified size.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`atChar(int i)`	Returns the character at the specified position in the buffer.
`boolean`	`backspace()`	Issue a backspace.
`int`	`backspace(int num)`	Issue num backspaces.
`boolean`	`clear()`	Clears the buffer content.
`BufferImpl`	`copy()`	Creates a copy of this buffer.
`void`	`copyFrom(Buffer buf)`	Copies the content and cursor position from another buffer.
`int`	`currChar()`	Returns the character at the current cursor position.
`boolean`	`currChar(int ch)`	Replaces the character at the current cursor position.
`int`	`cursor()`	Returns the current cursor position in the buffer.
`boolean`	`cursor(int position)`	Move the cursor position to the specified absolute index.
`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)`	Move the cursor where 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.
`java.lang.String`	`substring(int start)`	Returns a substring of the buffer from the specified start position to the end.
`java.lang.String`	`substring(int start, int end)`	Returns a substring of the buffer from the specified start position to the specified end position.
`java.lang.String`	`toString()`
`boolean`	`up()`	Moves the cursor up one line while maintaining the same column position if possible.
`java.lang.String`	`upToCursor()`	Returns a substring of the buffer from the beginning to the current cursor position.
`void`	`write(int c)`	Write the specific character into the buffer, setting the cursor position ahead one.
`void`	`write(int c, boolean overTyping)`	Write the specific character into the buffer, setting the cursor position ahead one.
`void`	`write(java.lang.CharSequence str)`	Insert the specified chars into the buffer, setting the cursor to the end of the insertion point.
`void`	`write(java.lang.CharSequence str, boolean overTyping)`	Writes a string at the current cursor position and advances the cursor.
`void`	`zeroOut()`	Clear any internal buffer.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - BufferImpl
```
public BufferImpl()
```
    Creates a new buffer with the default size (64).
  - BufferImpl
```
public BufferImpl(int size)
```
    Creates a new buffer with the specified size.
    
    Parameters:
    
    size - the initial size of the buffer
- Method Detail
  - copy
```
public BufferImpl copy()
```
    Description copied from interface: Buffer
    
    Creates a copy of this buffer.
    
    Specified by:
    
    copy in interface Buffer
    
    Returns:
    
    a new buffer with the same content and cursor position
  - cursor
```
public int cursor()
```
    Description copied from interface: Buffer
    
    Returns the current cursor position in the buffer.
    
    Specified by:
    
    cursor in interface Buffer
    
    Returns:
    
    the current cursor position (0-based index)
  - length
```
public int length()
```
    Description copied from interface: Buffer
    
    Returns the length of the buffer.
    
    Specified by:
    
    length in interface Buffer
    
    Returns:
    
    the number of characters in the buffer
  - currChar
```
public boolean currChar(int ch)
```
    Description copied from interface: Buffer
    
    Replaces the character at the current cursor position.
    
    Specified by:
    
    currChar in interface Buffer
    
    Parameters:
    
    ch - the character to set at the current position
    
    Returns:
    
    true if the buffer was modified
  - currChar
```
public int currChar()
```
    Description copied from interface: Buffer
    
    Returns the character at the current cursor position.
    
    Specified by:
    
    currChar in interface Buffer
    
    Returns:
    
    the character at the cursor position, or -1 if the cursor is at the end of the buffer
  - prevChar
```
public int prevChar()
```
    Description copied from interface: Buffer
    
    Returns the character before the current cursor position.
    
    Specified by:
    
    prevChar in interface Buffer
    
    Returns:
    
    the character before the cursor position, or -1 if the cursor is at the beginning of the buffer
  - nextChar
```
public int nextChar()
```
    Description copied from interface: Buffer
    
    Returns the character after the current cursor position.
    
    Specified by:
    
    nextChar in interface Buffer
    
    Returns:
    
    the character after the cursor position, or -1 if the cursor is at the end of the buffer
  - atChar
```
public int atChar(int i)
```
    Description copied from interface: Buffer
    
    Returns the character at the specified position in the buffer.
    
    Specified by:
    
    atChar in interface Buffer
    
    Parameters:
    
    i - the position to check
    
    Returns:
    
    the character at the specified position, or -1 if the position is invalid
  - write
```
public void write(int c)
```
    Write the specific character into the buffer, setting the cursor position ahead one.
    
    Specified by:
    
    write in interface Buffer
    
    Parameters:
    
    c - the character to insert
  - write
```
public void write(int c,
                  boolean overTyping)
```
    Write the specific character into the buffer, setting the cursor position ahead one. The text may overwrite or insert based on the current setting of overTyping.
    
    Specified by:
    
    write in interface Buffer
    
    Parameters:
    
    c - the character to insert
    
    overTyping - if true, overwrites the character at the current position
  - write
```
public void write(java.lang.CharSequence str)
```
    Insert the specified chars into the buffer, setting the cursor to the end of the insertion point.
    
    Specified by:
    
    write in interface Buffer
    
    Parameters:
    
    str - the string to write
  - write
```
public void write(java.lang.CharSequence str,
                  boolean overTyping)
```
    Description copied from interface: Buffer
    
    Writes a string at the current cursor position and advances the cursor.
    
    Specified by:
    
    write in interface Buffer
    
    Parameters:
    
    str - the string to write
    
    overTyping - if true, overwrites characters at the current position
  - clear
```
public boolean clear()
```
    Description copied from interface: Buffer
    
    Clears the buffer content.
    
    Specified by:
    
    clear in interface Buffer
    
    Returns:
    
    true if the buffer was modified
  - substring
```
public java.lang.String substring(int start)
```
    Description copied from interface: Buffer
    
    Returns a substring of the buffer from the specified start position to the end.
    
    Specified by:
    
    substring in interface Buffer
    
    Parameters:
    
    start - the start index, inclusive
    
    Returns:
    
    the substring
  - substring
```
public java.lang.String substring(int start,
                                  int end)
```
    Description copied from interface: Buffer
    
    Returns a substring of the buffer from the specified start position to the specified end position.
    
    Specified by:
    
    substring in interface Buffer
    
    Parameters:
    
    start - the start index, inclusive
    
    end - the end index, exclusive
    
    Returns:
    
    the substring
  - upToCursor
```
public java.lang.String upToCursor()
```
    Description copied from interface: Buffer
    
    Returns a substring of the buffer from the beginning to the current cursor position.
    
    Specified by:
    
    upToCursor in interface Buffer
    
    Returns:
    
    the substring
  - cursor
```
public boolean cursor(int position)
```
    Move the cursor position to the specified absolute index.
    
    Specified by:
    
    cursor in interface Buffer
    
    Parameters:
    
    position - the position to move the cursor to
    
    Returns:
    
    true if the cursor was moved, false if the position was invalid
  - move
```
public int move(int num)
```
    Move the cursor where characters.
    
    Specified by:
    
    move in interface Buffer
    
    Parameters:
    
    num - If less than 0, move abs(where) to the left, otherwise move where to the right.
    
    Returns:
    
    The number of spaces we moved
  - up
```
public boolean up()
```
    Description copied from interface: Buffer
    
    Moves the cursor up one line while maintaining the same column position if possible. This is used for multi-line editing.
    
    Specified by:
    
    up in interface Buffer
    
    Returns:
    
    true if the cursor was moved, false if it was already at the first line
  - down
```
public boolean down()
```
    Description copied from interface: Buffer
    
    Moves the cursor down one line while maintaining the same column position if possible. This is used for multi-line editing.
    
    Specified by:
    
    down in interface Buffer
    
    Returns:
    
    true if the cursor was moved, false if it was already at the last line
  - moveXY
```
public boolean moveXY(int dx,
                      int dy)
```
    Description copied from interface: Buffer
    
    Moves the cursor by the specified number of columns and rows. This is used for multi-line editing.
    
    Specified by:
    
    moveXY in interface Buffer
    
    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
  - backspace
```
public int backspace(int num)
```
    Issue num backspaces.
    
    Specified by:
    
    backspace in interface Buffer
    
    Parameters:
    
    num - the number of characters to delete
    
    Returns:
    
    the number of characters backed up
  - backspace
```
public boolean backspace()
```
    Issue a backspace.
    
    Specified by:
    
    backspace in interface Buffer
    
    Returns:
    
    true if successful
  - delete
```
public int delete(int num)
```
    Description copied from interface: Buffer
    
    Deletes multiple characters starting at the cursor position.
    
    Specified by:
    
    delete in interface Buffer
    
    Parameters:
    
    num - the number of characters to delete
    
    Returns:
    
    the number of characters actually deleted
  - delete
```
public boolean delete()
```
    Description copied from interface: Buffer
    
    Deletes the character at the cursor position.
    
    Specified by:
    
    delete in interface Buffer
    
    Returns:
    
    true if the buffer was modified
  - toString
```
public java.lang.String toString()
```
    Specified by:
    
    toString in interface Buffer
    
    Overrides:
    
    toString in class java.lang.Object
  - copyFrom
```
public void copyFrom(Buffer buf)
```
    Description copied from interface: Buffer
    
    Copies the content and cursor position from another buffer.
    
    Specified by:
    
    copyFrom in interface Buffer
    
    Parameters:
    
    buf - the buffer to copy from
  - zeroOut
```
public void zeroOut()
```
    Description copied from interface: Buffer
    
    Clear any internal buffer.
    
    Specified by:
    
    zeroOut in interface Buffer

Constructor	Description
`BufferImpl()`	Creates a new buffer with the default size (64).
`BufferImpl(int size)`	Creates a new buffer with the specified size.

Class BufferImpl

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BufferImpl

BufferImpl

Method Detail

copy

cursor

length

currChar

currChar

prevChar

nextChar

atChar

write

write

write

write

clear

substring

substring

upToCursor

cursor

move

up

down

moveXY

backspace

backspace

delete

delete

toString

copyFrom

zeroOut