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

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

All Implemented Interfaces:

BraceReduction

public class ReducedModelControl
extends Object
implements BraceReduction

This class provides an implementation of the BraceReduction interface for brace matching. In order to correctly match, this class keeps track of what is commented (line and block) and what is inside double quotes (strings). To avoid unnecessary complication, this class maintains a few invariants for its consistent states, i.e., between top-level function calls.

1. The cursor offset is never at the end of a brace. If movement or insertion puts it there, the cursor is updated to point to the 0 offset of the next brace. (token?)
2. Quoting information is invalid inside valid comments. When part of the document becomes uncommented, the reduced model must update the quoting information linearly in the newly revealed code.
3. Quote shadowing and comment shadowing are mutually exclusive.
4. There is no nesting of comment open characters. If // is encountered in the middle of a comment, it is treated as two separate slashes. Similarly for /*.

All of the code in the class assumes that the document read lock and the lock on this are held.

Version:

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

Author:

JavaPLT

Field Summary

(package private) int	_offset
(package private) ReducedModelBrace	_rmb
(package private) ReducedModelComment	_rmc

Constructor Summary

ReducedModelControl()
Standard constructor.

Method Summary

BraceInfo	_getEnclosingBrace() Gets info about the brace enclosing this location.
BraceInfo	_getLineEnclosingBrace() Gets info about the brace enclosing the beginning of this line.
int	absOffset() Gets the absolute character offset into the document represented by the reduced model.
(package private) boolean	atEnd() Determines if the cursor is at the end of the reduced model.
(package private) boolean	atStart() Determines if the cursor is at the start of the reduced model.
int	balanceBackward() Finds the open brace that matches the previous significant brace iff that brace is an closing brace.
int	balanceForward() Finds the closing brace that matches the next significant brace iff that brace is an open brace.
int	braceCursorOffset()
int	commentCursorOffset()
ReducedToken	currentToken() Gets the token currently pointed at by the cursor.
void	delete(int count) Updates the BraceReduction to reflect text deletion.
(package private) int	getBlockOffset() Gets the offset within the current token.
int	getDistToEnclosingBraceStart()
int	getDistToIdentNewline()
int	getDistToNextNewline() Gets distance to next new line.
int	getDistToStart() Gets distance to the new newline character (not including the newline).
int	getDistToStart(int relLoc) Gets distance to previous newline character (not including the newline).
ArrayList<HighlightStatus>	getHighlightStatus(int start, int length) Return all highlight status info for text between the current location and current location + length.
(package private) int	getSize() Gets the size of the current token.
(package private) int	getSize(ReducedToken rmbToken, ReducedToken rmcToken)
ReducedModelState	getStateAtCurrent() Gets the shadowing state at the current caret position.
(package private) String	getType() Get a string representation of the current token's type.
void	insertChar(char ch) Insert a character into the BraceReduction.
boolean	isShadowed() Determines if cursor position is shadowed by comment or string (does not include opening comment or quotation "brace").
boolean	isWeaklyShadowed() Determines if current token is either shadowed or an opening comment brace ("//" or "/*").
void	move(int count) Updates the BraceReduction to reflect cursor movement.
ReducedModelState	moveWalkerGetState(int relDistance) Returns the state at the relDistance, where relDistance is relative to the last time it was called.
(package private) void	next() Move the reduced model to the next token (with 0 offset) and update the cursor information.
ReducedToken	nextItem() Get the next token.
(package private) void	prev() Move the reduced model to the previous token and update the cursor information.
ReducedToken	prevItem() Get the previous token.
void	resetLocation() This function resets the location of the walker in the comment list to where the current cursor is.
String	simpleString() A toString() substitute.
int	walkerOffset()

Methods inherited from class java.lang.Object

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

Field Detail

_rmb

final ReducedModelBrace _rmb

_rmc

final ReducedModelComment _rmc

_offset

volatile int _offset

Constructor Detail

ReducedModelControl

public ReducedModelControl()

Standard constructor.

Method Detail

braceCursorOffset

public int braceCursorOffset()

Returns:

the absolute offset of the cursor in the brace model, which is expensive. Used for testing purposes only. This value should agree with commentCursorOffset().

commentCursorOffset

public int commentCursorOffset()

Returns:

the absolute offset of the cursor in the comment model, which is expensive. Used for testing purposes only. This value should agree with braceCursorOffset().

walkerOffset

public int walkerOffset()

Returns:

the absolute offset of the walker in the comment model, which is expensive. Used for testing purposes only.

insertChar

public void insertChar(char ch)

Description copied from interface: BraceReduction

Insert a character into the BraceReduction.

Specified by:

insertChar in interface BraceReduction

Parameters:

ch - the character to be inserted

move

public void move(int count)

Updates the BraceReduction to reflect cursor movement. Negative values move left; positive values move right. ASSUMES that count is within range, i.e. that 0 <= absOffset() + count <= getLength NOTE: this method does NOT move the _walker in ReduceModelComment.

Specified by:

move in interface BraceReduction

Parameters:

count - indicates the direction and magnitude of cursor movement

delete

public void delete(int count)

Updates the BraceReduction to reflect text deletion. Assumes that count is within range!

Specified by:

delete in interface BraceReduction

Parameters:

count - A number indicating the size and direction of text deletion. Negative values delete text to the left of the cursor, positive values delete text to the right.

isShadowed

public boolean isShadowed()

Determines if cursor position is shadowed by comment or string (does not include opening comment or quotation "brace").

isWeaklyShadowed

public boolean isWeaklyShadowed()

Determines if current token is either shadowed or an opening comment brace ("//" or "/*").

balanceForward

public int balanceForward()

Finds the closing brace that matches the next significant brace iff that brace is an open brace. Fails when brace is shadowed.

Specified by:

balanceForward in interface BraceReduction

Returns:

the distance until the matching closing brace. On failure, returns -1.

See Also:

balanceBackward()

balanceBackward

public int balanceBackward()

Finds the open brace that matches the previous significant brace iff that brace is an closing brace. Fails when brace is shadowed.

Specified by:

balanceBackward in interface BraceReduction

Returns:

the distance until the matching open brace. On failure, returns -1.

See Also:

balanceForward()

moveWalkerGetState

public ReducedModelState moveWalkerGetState(int relDistance)

Returns the state at the relDistance, where relDistance is relative to the last time it was called. You can reset the last call to the current offset using resetLocation.

Specified by:

moveWalkerGetState in interface BraceReduction

Parameters:

relDistance - distance from walker to get state at.

resetLocation

public void resetLocation()

This function resets the location of the walker in the comment list to where the current cursor is. This allows the walker to keep walking and using relative distance instead of having to rewalk the same distance every call to stateAtRelLocation. It is an optimization.

Specified by:

resetLocation in interface BraceReduction

currentToken

public ReducedToken currentToken()

Gets the token currently pointed at by the cursor. Because the reduced model is split into two reduced sub-models, we have to check each sub-model first as each one has unique information. If we find a non-gap token in either sub-model we want to return that. Otherwise, we want to return a sort of hybrid Gap of the two, i.e., a Gap where there are neither special comment/quote tokens nor parens/squigglies/brackets.

Specified by:

currentToken in interface BraceReduction

Returns:

a ReducedToken representative of the unified reduced model

getStateAtCurrent

public ReducedModelState getStateAtCurrent()

Gets the shadowing state at the current caret position.

Specified by:

getStateAtCurrent in interface BraceReduction

Returns:

FREE|INSIDE_LINE_COMMENT|INSIDE_BLOCK_COMMENT| INSIDE_SINGLE_QUOTE|INSIDE_DOUBLE_QUOTE

getType

String getType()

Get a string representation of the current token's type.

Returns:

"" if current is a Gap, otherwise, use ReducedToken.getType()

getSize

int getSize()

Gets the size of the current token. It checks both the brace and comment sub-models to find the size of the current token. If the current token is a Gap, we have to reconcile the information of both sub-models in order to get the correct size of the current token as seen by the outside world.

Returns:

the number of characters represented by the current token

getSize

int getSize(ReducedToken rmbToken,
            ReducedToken rmcToken)

next

void next()

Move the reduced model to the next token (with 0 offset) and update the cursor information.

prev

void prev()

Move the reduced model to the previous token and update the cursor information.

prevItem

public ReducedToken prevItem()

Get the previous token.

nextItem

public ReducedToken nextItem()

Get the next token.

atEnd

boolean atEnd()

Determines if the cursor is at the end of the reduced model.

atStart

boolean atStart()

Determines if the cursor is at the start of the reduced model.

getBlockOffset

int getBlockOffset()

Gets the offset within the current token.

absOffset

public int absOffset()

Gets the absolute character offset into the document represented by the reduced model.

Specified by:

absOffset in interface BraceReduction

simpleString

public String simpleString()

A toString() substitute.

Specified by:

simpleString in interface BraceReduction

getDistToIdentNewline

public int getDistToIdentNewline()

getDistToEnclosingBraceStart

public int getDistToEnclosingBraceStart()

_getLineEnclosingBrace

public BraceInfo _getLineEnclosingBrace()

Gets info about the brace enclosing the beginning of this line.

_getEnclosingBrace

public BraceInfo _getEnclosingBrace()

Gets info about the brace enclosing this location.

getDistToStart

public int getDistToStart()

Gets distance to the new newline character (not including the newline).

getDistToStart

public int getDistToStart(int relLoc)

Gets distance to previous newline character (not including the newline).

Specified by:

getDistToStart in interface BraceReduction

getDistToNextNewline

public int getDistToNextNewline()

Description copied from interface: BraceReduction

Gets distance to next new line.

Specified by:

getDistToNextNewline in interface BraceReduction

getHighlightStatus

public ArrayList<HighlightStatus> getHighlightStatus(int start,
                                                     int length)

Return all highlight status info for text between the current location and current location + length. This should collapse adjoining blocks with the same status into one. Assumes read and reduced locks are already held.

Specified by:

getHighlightStatus in interface BraceReduction

Parameters:

start - The start location of the area being inspected. The reduced model cursor is already set at this position, but this value is needed to compute the absolute positions of HighlightStatus objects.

length - The length of the text segment for which status information must be generated.