danger.util
Class TextBuffer

java.lang.Object
  |
  +--danger.util.TextBuffer

public class TextBuffer

extends java.lang.Object

This class implements the 'buffer-gap' method of storage management for a buffer that is frequently edited. This method assumes that there is a narrow locality to the editing taking place in a buffer, which is the common case for a text editor. 0 1 2 3 4 5 6 7 8 9 10 11 T | D | a | n | g | e | r | o | u | s | | | | | B | u | f | ----------------------------------------------------------------- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 B P GS GE This diagram illustrates how the buffer gap system works. P is the insertion/deletion (cursor) location in the current buffer GS is the start of the buffer gap GE is the end of the buffer gap When an editor action needs to be taken the gap is moved within the buffer so that GS is at the same location as P. For an insertion, the new character is added after GS and GS is moved to the right by one character, thus shrinking the gap. For a deletion, GS is simply moved one character to the left, growing the gap and causing future references to the text to skip over the deleted character. There are two index systems at work within the buffer. The first, labeled 'T' is the Text index. This indexes into the actual displayable text and skips over the characters that are the gap. The second, labeled 'B', is the Buffer index system. These are the positions used by the buffer routines. Note that they reference the spaces between characters rather than the characters themselves.

Constructor Summary

TextBuffer()

TextBuffer(int inInitialSize)

Method Summary

char	charAt(int index)
void	clear()
void	delete(int numChar)
void	deleteChar()
void	deleteLastWord()
void	drawText(Pen p, int x, int y, int offset, int length)
void	dumpBuffer()
void	dumpBuffer(Pen p, View v)
void	forwardDeleteChar()
char[]	getChars()
char[]	getChars(int inFirstChar, int inNumChars)
int	getLastNonWhiteSpaceCharPosition()
java.lang.String	getLastWord(char[] nonAlphaExceptionList)
int	getLastWordDelimPosition(char[] nonAlphaExceptionList)
int	getPoint()
int	getSelectionLength()
java.lang.String	getString()
java.lang.String	getString(int inFirstChar, int inNumChars)
void	growBuffer()
void	growBuffer(int inExtraSize)
void	insert(char inChar)
void	insert(java.lang.String inString)
int	length()
void	moveGapToPoint()
void	setChar(int position, char inChar)
void	setInputFilter(TextInputFilter inFilter)
void	setPoint(int inPosition)
void	setSelectionLength(int selectionLength)

Methods inherited from class java.lang.Object

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

Constructor Detail

TextBuffer

public TextBuffer()

TextBuffer

public TextBuffer(int inInitialSize)

Method Detail

drawText

public final void drawText(Pen p,
                           int x,
                           int y,
                           int offset,
                           int length)

moveGapToPoint

public void moveGapToPoint()

insert

public void insert(java.lang.String inString)

insert

public void insert(char inChar)

setChar

public void setChar(int position,
                    char inChar)

clear

public void clear()

deleteChar

public void deleteChar()

forwardDeleteChar

public void forwardDeleteChar()

delete

public void delete(int numChar)

deleteLastWord

public void deleteLastWord()

getLastWord

public java.lang.String getLastWord(char[] nonAlphaExceptionList)

getLastWordDelimPosition

public int getLastWordDelimPosition(char[] nonAlphaExceptionList)

getLastNonWhiteSpaceCharPosition

public int getLastNonWhiteSpaceCharPosition()

growBuffer

public void growBuffer()

growBuffer

public void growBuffer(int inExtraSize)

getPoint

public int getPoint()

setPoint

public void setPoint(int inPosition)

length

public int length()

charAt

public char charAt(int index)

getString

public java.lang.String getString()

getString

public java.lang.String getString(int inFirstChar,
                                  int inNumChars)

getChars

public char[] getChars()

getChars

public char[] getChars(int inFirstChar,
                       int inNumChars)

setInputFilter

public void setInputFilter(TextInputFilter inFilter)

dumpBuffer

public void dumpBuffer(Pen p,
                       View v)

dumpBuffer

public void dumpBuffer()

setSelectionLength

public void setSelectionLength(int selectionLength)

getSelectionLength

public int getSelectionLength()