edu.rice.cs.drjava.model.definitions.reducedmodel
Class AbstractReducedModel

java.lang.Object
  edu.rice.cs.drjava.model.definitions.reducedmodel.AbstractReducedModel

All Implemented Interfaces:

ReducedModelStates

Direct Known Subclasses:

ReducedModelBrace, ReducedModelComment

public abstract class AbstractReducedModel
extends Object
implements ReducedModelStates

A refactoring of the common code between ReducedModelComment and ReducedModelBrace. Both of the refactored classes extend this class.

Version:

$Id: AbstractReducedModel.java 5175 2010-01-20 08:46:32Z mgricken $

Author:

JavaPLT

Field Summary

(package private) TokenList.Iterator	_cursor Keeps track of cursor position in document.
(package private) TokenList	_tokens The reduced model for a document is a list of ReducedTokens (braces and gaps).
static char	PTR_CHAR The character that represents the cursor in toString().

Fields inherited from interface edu.rice.cs.drjava.model.definitions.reducedmodel.ReducedModelStates

FREE, INSIDE_BLOCK_COMMENT, INSIDE_DOUBLE_QUOTE, INSIDE_LINE_COMMENT, INSIDE_SINGLE_QUOTE, STUTTER

Constructor Summary

AbstractReducedModel()
Constructor.

Method Summary

protected void	_augmentCurrentGap(int length) Assuming there is a gap to the right, this function increases the size of that gap.
protected void	_augmentGapToLeft(int length) Assuming there is a gap to the left, this function increases the size of that gap.
protected boolean	_gapToLeft() Determines if there is a gap immediately to the left of the cursor.
protected boolean	_gapToRight() Determines if there is a Gap immediately to the right of the cursor.
void	_insertGap(int length) Inserts a block of text into the reduced model which has no special consideration in the reduced model.
protected void	_insertNewGap(int length) Helper function for _insertGap.
int	absOffset() Absolute offset for testing purposes.
int	absOffset(TokenList.Iterator cursor) Absolute offset of the specified iterator.
protected ReducedToken	current() Get the ReducedToken currently pointed at by the cursor.
(package private) int	getBlockOffset() Get the offset into the current ReducedToken.
int	getLength()
ReducedModelState	getState()
abstract void	insertChar(char ch) Inserts a character into the reduced model.
protected abstract void	insertGapBetweenMultiCharBrace(int length) Inserts a gap between a multiple character brace.
TokenList.Iterator	makeCopyCursor() Make a copy of the token list's iterator.
protected abstract ReducedModelState	moveWalkerGetState(int relLocation) Returns the state at the relLocation, where relLocation is the location relative to the walker.
protected void	next() Move to the token immediately right.
protected void	prev() Move to the token immediately left.
protected abstract void	resetWalkerLocationToCursor() Resets the walker to the current position in document.
(package private) void	setBlockOffset(int offset) Change the offset into the current ReducedToken.
String	simpleString() A toString() replacement for testing - easier to read.

Methods inherited from class java.lang.Object

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

Field Detail

PTR_CHAR

public static final char PTR_CHAR

The character that represents the cursor in toString(). @see #toString()

See Also:

Constant Field Values

_tokens

TokenList _tokens

The reduced model for a document is a list of ReducedTokens (braces and gaps).

_cursor

TokenList.Iterator _cursor

Keeps track of cursor position in document.

Constructor Detail

AbstractReducedModel

public AbstractReducedModel()

Constructor. Creates a new reduced model with the cursor at the start of a blank "page."

Method Detail

getBlockOffset

int getBlockOffset()

Get the offset into the current ReducedToken.

Returns:

the number of characters into the token where the cursor sits

setBlockOffset

void setBlockOffset(int offset)

Change the offset into the current ReducedToken.

Parameters:

offset - the number of characters into the token to set the cursor

absOffset

public int absOffset()

Absolute offset for testing purposes. We don't keep track of absolute offset as it causes too much confusion and trouble.

absOffset

public int absOffset(TokenList.Iterator cursor)

Absolute offset of the specified iterator. Inefficient so only used for testing purposes.

getLength

public int getLength()

getState

public ReducedModelState getState()

simpleString

public String simpleString()

A toString() replacement for testing - easier to read.

insertChar

public abstract void insertChar(char ch)

Inserts a character into the reduced model. A method to be implemented in each specific reduced sub-model.

_insertGap

public void _insertGap(int length)

Inserts a block of text into the reduced model which has no special consideration in the reduced model.

1. atStart: if gap to right, augment first gap, else insert
2. atEnd: if gap to left, augment left gap, else insert
3. inside a gap: grow current gap, move offset by length
4. inside a multiple character brace:
   1. break current brace
   2. insert new gap
5. gap to left: grow that gap and set offset to zero
6. gap to right: this case handled by inside gap (offset invariant)
7. between two braces: insert new gap

   Parameters:

   length - the length of the inserted text

insertGapBetweenMultiCharBrace

protected abstract void insertGapBetweenMultiCharBrace(int length)

Inserts a gap between a multiple character brace. Because ReducedModelBrace does not keep track of multiple character braces, only (),{}, and [], it differed in its implementation of inserGap(int) from ReducedModelComment's. To pull out the otherwise identical code and place it here, we created this function to do something meaningful in ReducedModelComment and to throw an exception in ReducedModelBrace.

makeCopyCursor

public TokenList.Iterator makeCopyCursor()

Make a copy of the token list's iterator.

_gapToRight

protected boolean _gapToRight()

Determines if there is a Gap immediately to the right of the cursor.

_gapToLeft

protected boolean _gapToLeft()

Determines if there is a gap immediately to the left of the cursor.

_augmentGapToLeft

protected void _augmentGapToLeft(int length)

Assuming there is a gap to the left, this function increases the size of that gap.

Parameters:

length - the amount of increase

_augmentCurrentGap

protected void _augmentCurrentGap(int length)

Assuming there is a gap to the right, this function increases the size of that gap.

Parameters:

length - the amount of increase

_insertNewGap

protected void _insertNewGap(int length)

Helper function for _insertGap. Performs the actual insert and marks the offset appropriately.

Parameters:

length - size of gap to insert

moveWalkerGetState

protected abstract ReducedModelState moveWalkerGetState(int relLocation)

Returns the state at the relLocation, where relLocation is the location relative to the walker.

Parameters:

relLocation - distance from walker to get state at.

resetWalkerLocationToCursor

protected abstract void resetWalkerLocationToCursor()

Resets the walker to the current position in document.

current

protected ReducedToken current()

Get the ReducedToken currently pointed at by the cursor.

Returns:

the current token

next

protected void next()

Move to the token immediately right. This function forwards its responsibilities to the cursor. If the cursor is at the end, it will throw an exception.

prev

protected void prev()

Move to the token immediately left. This function forwards its responsibilities to the TokenList iterator. If the cursor is at the start, it will throw an exception.