condor.classad
Class ClassAdWriter

Object
  Writer
      PrintWriter
          condor.classad.ClassAdWriter

public class ClassAdWriter

extends PrintWriter

A tool for converting classads to characters in a variety of formats. A ClassAdWriter behaves like a java.io.PrintWriter except that it has two additional methods print(Expr) and println(Expr). An instance has an associated representation and set of options.

Currently, we support two representations:

NATIVE

The "native" ASCII representation, e.g.

    [ my_string = "abc"; my_list = {1, 2, x + 1};]
 

XML

An XML (Extensible Markup Language) representation, e.g.

     <c>
         <a n="my_string"><s>abc</s></a>
         <a n="my_list"><l> <n>1</n> <n>2</n> <e>x+1</e> </l></a>
     </c>
 

The third representation is "OLD" classads, supported only for compatibility with a previous version C++ implementation of classified advertisements. Only RecordExprs can be represented in this format, and the format is inherently binary, requiring a DataOutput. To represent an ad in the OLD format, use RecordExpr.transmit(java.io.DataOutput).

Other external representations may be added in the future.

Options provide finer control over the output format, for example, the native representation may be formatted for readability (e.g. listing each attribute of a RecordExpression on a separate line) or for compactness. By default, a ClassAdWriter uses NATIVE representation and formats the same as Expr.toString() so that code such as

     Expr e = ...;
     ClassAdWriter out = new ClassAdWriter(System.out);
     out.println(e)
 

has the same effect as

     Expr e = ...;
     System.out.println(e);
 

However, a ClassAdWriter allows more control over representation and formatting details. It also may be more efficient for large expressions, since the string representation doesn't need to be assembled in memory before being printed.

Version:

2.2

Author:

Marvin Solomon

Field Summary

static int	BRIEF A combination of option flags for formatFlags.
static int	COMPACT A combination of option flags for formatFlags.
static int	JAVA_REALS An option flag for formatFlags.
static int	MINIMAL_PARENTHESES An option flag for formatFlags.
static int	MULTI_LINE_ADS An option flag for formatFlags.
static int	MULTI_LINE_LISTS An option flag for formatFlags.
static int	NATIVE Native output representation (e.g.
static int	NO_ESCAPE_STRINGS An option flag for formatFlags.
static int	READABLE A combination of option flags for formatFlags.
static int	SHOW_ERROR_DETAIL An option flag for formatFlags.
static int	XML XML output representation (e.g.

Fields inherited from class PrintWriter

out

Fields inherited from class Writer

lock

Constructor Summary

ClassAdWriter(OutputStream out)
Creates a new ClassAdWriter for writing to an existing OutputStream using the NATIVE representation, without automatic line flushing.

ClassAdWriter(OutputStream out, boolean autoFlush)
Creates a new ClassAdWriter for writing to an existing OutputStream using the NATIVE representation.

ClassAdWriter(OutputStream out, int representation)
Creates a new ClassAdWriter for writing to an existing OutputStream in a given representation, without automatic line flushing.

ClassAdWriter(OutputStream out, int representation, boolean autoFlush)
Creates a new ClassAdWriter for writing to an existing OutputStream in a given representation.

ClassAdWriter(Writer out)
Creates a new ClassAdWriter for writing to an existing Writer using the NATIVE representation, without automatic line flushing.

ClassAdWriter(Writer out, boolean autoFlush)
Creates a new ClassAdWriter for writing to an existing Writer using the NATIVE representation.

ClassAdWriter(Writer out, int representation)
Creates a new ClassAdWriter for writing to an existing Writer in a given representation, without automatic line flushing.

ClassAdWriter(Writer out, int representation, boolean autoFlush)
Creates a new ClassAdWriter for writing to an existing Writer in a given representation.

Method Summary

void	close() Close this writer.
void	disableFormatFlags(int flags) Turn off options for converting expressions to strings.
void	enableFormatFlags(int flags) Turn on options for converting expressions to strings.
int	getFormatFlags() Get existing options for converting expressions to strings.
int	getRepresentation() Get the current output representation.
void	print(Expr exp) Print a classad expression.
void	println(Expr exp) Print a classad expression and then terminate the line.
void	setFormatFlags(int flags) Set options for converting expressions to strings.
void	setRepresentation(int representation) Change the output representation.

Methods inherited from class PrintWriter

checkError, flush, print, print, print, print, print, print, print, print, print, println, println, println, println, println, println, println, println, println, println, setError, write, write, write, write, write

Methods inherited from class Object

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

Field Detail

NATIVE

public static final int NATIVE

Native output representation (e.g. [a=x+1]).

See Also:

Constant Field Values

XML

public static final int XML

XML output representation (e.g. <c><a name="a"><e>x+1</e></a></c> ).

See Also:

Constant Field Values

NO_ESCAPE_STRINGS

public static final int NO_ESCAPE_STRINGS

An option flag for formatFlags. Don't surround strings with quotes or escape special characters in the string.

WARNING: Strings created with this flag cannot be parsed to recover the expressions that created them.

See Also:

setFormatFlags(int), Constant Field Values

SHOW_ERROR_DETAIL

public static final int SHOW_ERROR_DETAIL

An option flag for formatFlags. Print the ERROR value as "ERROR(reason)" rather than just "ERROR", and similarly for UNDEFINED.

See Also:

setFormatFlags(int), Constant Field Values

MINIMAL_PARENTHESES

public static final int MINIMAL_PARENTHESES

An option flag for formatFlags. Use only as many parentheses are are required to override the default precendence of operators.

See Also:

setFormatFlags(int), Constant Field Values

MULTI_LINE_ADS

public static final int MULTI_LINE_ADS

An option flag for formatFlags. Display classads with one attribute per line.

See Also:

setFormatFlags(int), Constant Field Values

MULTI_LINE_LISTS

public static final int MULTI_LINE_LISTS

An option flag for formatFlags. Display lists with one member per line.

See Also:

setFormatFlags(int), Constant Field Values

JAVA_REALS

public static final int JAVA_REALS

An option flag for formatFlags. Use the default Java representation for reals rather than always using exponential notation. For example, print 12345 rather than 1.2345E4.

See Also:

setFormatFlags(int), Constant Field Values

BRIEF

public static final int BRIEF

A combination of option flags for formatFlags. Produce a concise version: MINIMAL_PARENTHESES, NO_ESCAPE_STRINGS, and JAVA_REALS.

See Also:

setFormatFlags(int), MINIMAL_PARENTHESES, NO_ESCAPE_STRINGS, JAVA_REALS, Constant Field Values

COMPACT

public static final int COMPACT

A combination of option flags for formatFlags. Produce a compact but parsable version: MINIMAL_PARENTHESES and JAVA_REALS.

See Also:

setFormatFlags(int), MINIMAL_PARENTHESES, JAVA_REALS, Constant Field Values

READABLE

public static final int READABLE

A combination of option flags for formatFlags. Produce a maximally-readable version (all flags set).

See Also:

setFormatFlags(int), Constant Field Values

Constructor Detail

ClassAdWriter

public ClassAdWriter(OutputStream out,
                     int representation,
                     boolean autoFlush)

Creates a new ClassAdWriter for writing to an existing OutputStream in a given representation. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

representation - the representation (one of NATIVE or XML).

autoFlush - if true, the println() methods will flush the output buffer.

ClassAdWriter

public ClassAdWriter(OutputStream out,
                     int representation)

Creates a new ClassAdWriter for writing to an existing OutputStream in a given representation, without automatic line flushing. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

representation - the representation (one of NATIVE or XML).

ClassAdWriter

public ClassAdWriter(OutputStream out,
                     boolean autoFlush)

Creates a new ClassAdWriter for writing to an existing OutputStream using the NATIVE representation. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

autoFlush - if true, the println() methods will flush the output buffer.

ClassAdWriter

public ClassAdWriter(OutputStream out)

Creates a new ClassAdWriter for writing to an existing OutputStream using the NATIVE representation, without automatic line flushing. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

ClassAdWriter

public ClassAdWriter(Writer out,
                     int representation,
                     boolean autoFlush)

Creates a new ClassAdWriter for writing to an existing Writer in a given representation. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

representation - the representation (one of NATIVE or XML).

autoFlush - if true, the println() methods will flush the output buffer.

ClassAdWriter

public ClassAdWriter(Writer out,
                     int representation)

Creates a new ClassAdWriter for writing to an existing Writer in a given representation, without automatic line flushing. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

representation - the representation (one of NATIVE or XML).

ClassAdWriter

public ClassAdWriter(Writer out,
                     boolean autoFlush)

Creates a new ClassAdWriter for writing to an existing Writer using the NATIVE representation. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

autoFlush - if true, the println() methods will flush the output buffer.

ClassAdWriter

public ClassAdWriter(Writer out)

Creates a new ClassAdWriter for writing to an existing Writer using the NATIVE representation, without automatic line flushing. Characters are converted to bytes using the default character encoding.

Parameters:

out - the desitination for output.

Method Detail

setRepresentation

public void setRepresentation(int representation)

Change the output representation. Note If the initial representation set by the constructor was XML, the output is "wrapped" by

     <?xml version=\"1.0\"?>
     <!DOCTYPE classads>
     <classads>
     ...
     </classads>
 

and the final </classads> is output by the close() method regardless of the current representation.

Parameters:

representation - the new representation: one of XML or NATIVE.

See Also:

setFormatFlags(int), getRepresentation()

getRepresentation

public int getRepresentation()

Get the current output representation.

Returns:

the current output representation, either XML or NATIVE.

See Also:

setRepresentation(int)

setFormatFlags

public void setFormatFlags(int flags)

Set options for converting expressions to strings.

Parameters:

flags - the new flag values.

See Also:

NO_ESCAPE_STRINGS, SHOW_ERROR_DETAIL, MINIMAL_PARENTHESES, JAVA_REALS, MULTI_LINE_ADS, MULTI_LINE_LISTS, BRIEF, COMPACT, READABLE, getFormatFlags()

getFormatFlags

public int getFormatFlags()

Get existing options for converting expressions to strings.

Returns:

the current option flags.

See Also:

NO_ESCAPE_STRINGS, SHOW_ERROR_DETAIL, MINIMAL_PARENTHESES, JAVA_REALS, MULTI_LINE_ADS, MULTI_LINE_LISTS, BRIEF, COMPACT, READABLE, setFormatFlags(int)

enableFormatFlags

public void enableFormatFlags(int flags)

Turn on options for converting expressions to strings.

Parameters:

flags - the flag values to be enabled

See Also:

NO_ESCAPE_STRINGS, SHOW_ERROR_DETAIL, MINIMAL_PARENTHESES, JAVA_REALS, MULTI_LINE_ADS, MULTI_LINE_LISTS, BRIEF, COMPACT, READABLE

disableFormatFlags

public void disableFormatFlags(int flags)

Turn off options for converting expressions to strings.

Parameters:

flags - the flag values to be disabled

See Also:

NO_ESCAPE_STRINGS, SHOW_ERROR_DETAIL, MINIMAL_PARENTHESES, JAVA_REALS, MULTI_LINE_ADS, MULTI_LINE_LISTS, BRIEF, COMPACT, READABLE

println

public void println(Expr exp)

Print a classad expression and then terminate the line. This method behaves as though it invokes print(Expr) and then println().

Parameters:

exp - the expression to be printed.

print

public void print(Expr exp)

Print a classad expression.

Parameters:

exp - the expression to be printed.

close

public void close()

Close this writer.