polyglot.util

Class CodeWriter

java.lang.Object

polyglot.util.CodeWriter

All Implemented Interfaces:

java.lang.AutoCloseable

Direct Known Subclasses:

OptimalCodeWriter, SimpleCodeWriter

public abstract class CodeWriter
extends java.lang.Object
implements java.lang.AutoCloseable

A CodeWriter is a pretty-printing engine. It formats structured text onto an output stream o in the minimum number of lines, while keeping the width of the output within width characters if possible. Newlines occur in the output only at places where a line break is permitted by the use of allowBreak and unifiedBreak. Line breaks can have different levels, which is useful for implementing things like "miser mode" layout.

Constructor Summary

Constructors

Constructor and Description
CodeWriter()

Method Summary

Methods

Modifier and Type	Method and Description
void	allowBreak(int n) The most common use of "allowBreak": level 1, with an alternative of a single space.
abstract void	allowBreak(int n, int level, java.lang.String alt, int altlen) Insert a break (an optional newline).
void	allowBreak(int n, java.lang.String alt)
abstract void	begin(int n) Start a new block with a relative indentation of n characters.
abstract void	close() Flush all formatted text, reset formatter state, and close the underlying writer.
abstract void	end() Terminate the most recent outstanding begin.
abstract boolean	flush() Flush all formatted text to the underlying writer.
abstract boolean	flush(boolean format) Like flush, but passing format=false causes output to be generated in the fastest way possible, with all breaks broken.
void	newline() Force a newline.
void	newline(int n) Like newline(), but forces a newline with a specified indentation.
abstract void	newline(int n, int level) newline with a specified indentation and level.
abstract java.lang.String	toString() Return a readable representation of all the structured input given to the CodeWriter since the last flush.
void	unifiedBreak(int n) The most common use of "unifiedBreak": level 1, with an alternative of a single space.
abstract void	unifiedBreak(int n, int level, java.lang.String alt, int altlen) Insert a unified break.
abstract void	write(java.lang.String s) Print the string s verbatim on the output stream.
abstract void	write(java.lang.String s, int length) Print the string s on the output stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

CodeWriter

public CodeWriter()

Method Detail

write

public abstract void write(java.lang.String s)

Print the string s verbatim on the output stream.

Parameters:

s - the string to print.

write

public abstract void write(java.lang.String s,
         int length)

Print the string s on the output stream. Pretend that it has width length even if it has a different number of characters. This is useful when the string contains escape sequences, HTML character entity references, etc.

Parameters:

s -

length -

begin

public abstract void begin(int n)

Start a new block with a relative indentation of n characters.

end

public abstract void end()

Terminate the most recent outstanding begin.

allowBreak

public abstract void allowBreak(int n,
              int level,
              java.lang.String alt,
              int altlen)

Insert a break (an optional newline). Indentation will be preserved. Every break has a level. A level 0 break is always broken to form a newline. The code writer tries to avoid breaking higher-level breaks, and the higher the level, the harder it tries.

Parameters:

n - indentation relative to the current block if the newline is inserted. Requires: n >= 0

level - the level of the break. Requires: level >= 0

alt - if no newline is inserted, the string alt is output instead. Requires: alt != null

altlen - the length of 'alt' in characters

unifiedBreak

public abstract void unifiedBreak(int n,
                int level,
                java.lang.String alt,
                int altlen)

Insert a unified break. Unified breaks act like the breaks inserted by allowBreak, but unified breaks should also break if any break of the same level in the same block is broken, whereas ordinary breaks do not necessarily break in this case. That is, unified breaks act as if they were slightly lower level than other breaks of the same level (including other unified breaks!).

Parameters:

n - the relative indentation

level - the level of the break

alt - the alternative text

altlen - the length in characters that 'alt' will be treated as taking up.

See Also:

allowBreak(int, int, java.lang.String, int)

unifiedBreak

public void unifiedBreak(int n)

The most common use of "unifiedBreak": level 1, with an alternative of a single space.

Parameters:

n - the indentation relative to the current block.

allowBreak

public void allowBreak(int n)

The most common use of "allowBreak": level 1, with an alternative of a single space.

Parameters:

n - the indentation relative to the current block.

allowBreak

public void allowBreak(int n,
              java.lang.String alt)

newline

public void newline()

Force a newline. Indentation will be preserved. This method should be used sparingly; a call to allowBreak() gives the pretty-printer much more flexibility to do a good job.

newline

public void newline(int n)

Like newline(), but forces a newline with a specified indentation.

newline

public abstract void newline(int n,
           int level)

newline with a specified indentation and level.

flush

public abstract boolean flush()
                       throws java.io.IOException

Flush all formatted text to the underlying writer. Returns true if formatting was completely successful (the margins were obeyed).

Throws:

java.io.IOException

close

public abstract void close()
                    throws java.io.IOException

Flush all formatted text, reset formatter state, and close the underlying writer.

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException

flush

public abstract boolean flush(boolean format)
                       throws java.io.IOException

Like flush, but passing format=false causes output to be generated in the fastest way possible, with all breaks broken.

Parameters:

format - whether to pretty-print the output

Returns:

whether formatting was completely successful.

Throws:

java.io.IOException

toString

public abstract java.lang.String toString()

Return a readable representation of all the structured input given to the CodeWriter since the last flush.

Overrides:

toString in class java.lang.Object