Class AutoIndentWriter

java.lang.Object

org.antlr.stringtemplate.AutoIndentWriter

All Implemented Interfaces:

StringTemplateWriter

Direct Known Subclasses:

NoIndentWriter

public class AutoIndentWriter
extends Object
implements StringTemplateWriter

Essentially a char filter that knows how to auto-indent output by maintaining a stack of indent levels. I set a flag upon newline and then next nonwhitespace char resets flag and spits out indention. The indent stack is a stack of strings so we can repeat original indent not just the same number of columns (don't have to worry about tabs vs spaces then). Anchors are char positions (tabs won't work) that indicate where all future wraps should justify to. The wrap position is actually the larger of either the last anchor or the indentation level. This is a filter on a Writer. \n is the proper way to say newline for options and templates. Templates can mix them but use \n for sure and options like wrap="\n". ST will generate the right thing. Override the default (locale) newline by passing in a string to the constructor.

Field Summary

Fields

Modifier and Type	Field	Description
protected int[]	anchors	Stack of integer anchors (char positions in line); avoid Integer creation overhead.
protected int	anchors_sp
protected boolean	atStartOfLine
protected int	charPosition	Track char position in the line (later we can think about tabs).
protected int	charPositionOfStartOfExpr
protected List	indents	stack of indents; use List as it's much faster than Stack.
protected int	lineWidth
protected String	newline	\n or \r\n?
protected Writer	out

Fields inherited from interface StringTemplateWriter

NO_WRAP

Constructor Summary

Constructors

Constructor	Description
AutoIndentWriter(Writer out)
AutoIndentWriter(Writer out, String newline)

Method Summary

Modifier and Type	Method	Description
int	getIndentationWidth()
protected StringBuffer	getIndentString(int spaces)
int	indent()
int	indent(int spaces)
void	popAnchorPoint()
String	popIndentation()
void	pushAnchorPoint()
void	pushIndentation(String indent)	Push even blank (null) indents as they are like scopes; must be able to pop them back off stack.
void	setLineWidth(int lineWidth)
int	write(String str)	Write out a string literal or attribute expression or expression element.
int	write(String str, String wrap)	Write out a string literal or attribute expression or expression element.
int	writeSeparator(String str)	Write a separator.
int	writeWrapSeparator(String wrap)	Because we might need to wrap at a non-atomic string boundary (such as when we wrap in between template applications invalid input: '<'data:{v|[]}; wrap>) we need to expose the wrap string writing just like for the separator.

Methods inherited from class Object

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

Field Details

indents

protected List indents

stack of indents; use List as it's much faster than Stack. Grows from 0..n-1. List

anchors

protected int[] anchors

Stack of integer anchors (char positions in line); avoid Integer creation overhead.

anchors_sp

protected int anchors_sp

newline

protected String newline

\n or \r\n?

out

protected Writer out

atStartOfLine

protected boolean atStartOfLine

charPosition

protected int charPosition

Track char position in the line (later we can think about tabs). Indexed from 0. We want to keep charPosition invalid input: '<'= lineWidth. This is the position we are *about* to write not the position last written to.

lineWidth

protected int lineWidth

charPositionOfStartOfExpr

protected int charPositionOfStartOfExpr

Constructor Details

AutoIndentWriter

public AutoIndentWriter(Writer out,
 String newline)

AutoIndentWriter

public AutoIndentWriter(Writer out)

Method Details

setLineWidth

public void setLineWidth(int lineWidth)

Specified by:

setLineWidth in interface StringTemplateWriter

pushIndentation

public void pushIndentation(String indent)

Push even blank (null) indents as they are like scopes; must be able to pop them back off stack. To deal with combined anchors and indentation, force indents to include any current anchor point. If current anchor is beyond current indent width, add the difference to the indent to be added. This prevents a check later to deal with anchors when starting new line.

Specified by:

pushIndentation in interface StringTemplateWriter

popIndentation

public String popIndentation()

Specified by:

popIndentation in interface StringTemplateWriter

pushAnchorPoint

public void pushAnchorPoint()

Specified by:

pushAnchorPoint in interface StringTemplateWriter

popAnchorPoint

public void popAnchorPoint()

Specified by:

popAnchorPoint in interface StringTemplateWriter

getIndentationWidth

public int getIndentationWidth()

write

public int write(String str)
          throws IOException

Write out a string literal or attribute expression or expression element.

Specified by:

write in interface StringTemplateWriter

Throws:

IOException

writeSeparator

public int writeSeparator(String str)
                   throws IOException

Description copied from interface: StringTemplateWriter

Write a separator. Same as write() except that a \n cannot be inserted before emitting a separator.

Specified by:

writeSeparator in interface StringTemplateWriter

Throws:

IOException

write

public int write(String str,
 String wrap)
          throws IOException

Write out a string literal or attribute expression or expression element. If doing line wrap, then check wrap before emitting this str. If at or beyond desired line width then emit a \n and any indentation before spitting out this str.

Specified by:

write in interface StringTemplateWriter

Throws:

IOException

writeWrapSeparator

public int writeWrapSeparator(String wrap)
                       throws IOException

Description copied from interface: StringTemplateWriter

Because we might need to wrap at a non-atomic string boundary (such as when we wrap in between template applications invalid input: '<'data:{v|[]}; wrap>) we need to expose the wrap string writing just like for the separator.

Specified by:

writeWrapSeparator in interface StringTemplateWriter

Throws:

IOException

indent

public int indent()
           throws IOException

Throws:

IOException

indent

public int indent(int spaces)
           throws IOException

Throws:

IOException

getIndentString

protected StringBuffer getIndentString(int spaces)