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ChoiceFormat Class Reference

#include <choicfmt.h>

Inheritance diagram for ChoiceFormat:

NumberFormat Format

Public Member Functions

 ChoiceFormat (const UnicodeString &newPattern, UErrorCode &status)
 Construct a new ChoiceFormat with the limits and the corresponding formats based on the pattern.
 ChoiceFormat (const double *limits, const UnicodeString *formats, int32_t count)
 Construct a new ChoiceFormat with the given limits and formats.
 ChoiceFormat (const double *limits, const UBool *closures, const UnicodeString *formats, int32_t count)
 Construct a new ChoiceFormat with the given limits and formats.
 ChoiceFormat (const ChoiceFormat &)
 Copy constructor.
const ChoiceFormatoperator= (const ChoiceFormat &)
 Assignment operator.
virtual ~ChoiceFormat ()
 Destructor.
virtual Formatclone (void) const
 Clone this Format object polymorphically.
virtual UBool operator== (const Format &other) const
 Return true if the given Format objects are semantically equal.
virtual void applyPattern (const UnicodeString &pattern, UErrorCode &status)
 Sets the pattern.
virtual void applyPattern (const UnicodeString &pattern, UParseError &parseError, UErrorCode &status)
 Sets the pattern.
virtual UnicodeStringtoPattern (UnicodeString &pattern) const
 Gets the pattern.
virtual void adoptChoices (double *limitsToAdopt, UnicodeString *formatsToAdopt, int32_t count)
 Set the choices to be used in formatting.
virtual void adoptChoices (double *limitsToAdopt, UBool *closuresToAdopt, UnicodeString *formatsToAdopt, int32_t count)
 Set the choices to be used in formatting.
virtual void setChoices (const double *limitsToCopy, const UnicodeString *formatsToCopy, int32_t count)
 Set the choices to be used in formatting.
virtual void setChoices (const double *limits, const UBool *closures, const UnicodeString *formats, int32_t count)
 Set the choices to be used in formatting.
virtual const double * getLimits (int32_t &count) const
 Get the limits passed in the constructor.
virtual const UBool * getClosures (int32_t &count) const
 Get the limit booleans passed in the constructor.
virtual const UnicodeStringgetFormats (int32_t &count) const
 Get the formats passed in the constructor.
virtual UnicodeStringformat (double number, UnicodeString &toAppendTo, FieldPosition &pos) const
 Format a double or long number using this object's choices.
virtual UnicodeStringformat (int32_t number, UnicodeString &toAppendTo, FieldPosition &pos) const
 Format a int_32t number using this object's choices.
virtual UnicodeStringformat (const Formattable *objs, int32_t cnt, UnicodeString &toAppendTo, FieldPosition &pos, UErrorCode &success) const
 Format an array of objects using this object's choices.
virtual UnicodeStringformat (const Formattable &obj, UnicodeString &toAppendTo, FieldPosition &pos, UErrorCode &status) const
 Format an object using this object's choices.
UnicodeStringformat (const Formattable &obj, UnicodeString &result, UErrorCode &status) const
 Redeclared NumberFormat method.
UnicodeStringformat (double number, UnicodeString &output) const
 Redeclared NumberFormat method.
UnicodeStringformat (int32_t number, UnicodeString &output) const
 Redeclared NumberFormat method.
virtual void parse (const UnicodeString &text, Formattable &result, ParsePosition &parsePosition) const
 Return a long if possible (e.g.
virtual void parse (const UnicodeString &text, Formattable &result, UErrorCode &status) const
 Parse a string as a numeric value, and return a Formattable numeric object.
virtual UClassID getDynamicClassID (void) const
 Returns a unique class ID POLYMORPHICALLY.

Static Public Member Functions

static UClassID getStaticClassID (void)
 Return the class ID for this class.
static double nextDouble (double d, UBool positive)
static double nextDouble (double d)
 Finds the least double greater than d.
static double previousDouble (double d)
 Finds the greatest double less than d.

Friends

class MessageFormat

Detailed Description

ChoiceFormat converts between ranges of numeric values and string names for those ranges. A ChoiceFormat splits the real number line -Inf to +Inf into two or more contiguous ranges. Each range is mapped to a string. ChoiceFormat is generally used in a MessageFormat for displaying grammatically correct plurals such as "There are 2 files."

There are two methods of defining a ChoiceFormat; both are equivalent. The first is by using a string pattern. This is the preferred method in most cases. The second method is through direct specification of the arrays that make up the ChoiceFormat.

Patterns

In most cases, the preferred way to define a ChoiceFormat is with a pattern. Here is an example of a ChoiceFormat pattern:

    0are no files|1is one file|1<are many files

The pattern consists of a number or range specifiers separated by vertical bars U+007C (|). There is no vertical bar after the last range. Each range specifier is of the form number separator string.

Number is a floating point number that can be parsed by a default NumberFormat for the US locale. It gives the lower limit of this range. The lower limit is either inclusive or exclusive, depending on the separator. (The upper limit is given by the lower limit of the next range.) The Unicode infinity sign U+221E is recognized for positive infinity. It may be preceded by '-' (U+002D) to indicate negative infinity.

String is the format string for this range, with special characters enclosed in single quotes ('The # sign'). Single quotes themselves are indicated by two single quotes in a row ('o''clock').

Separator is one of the following single characters:

See below for more information about closures.

Arrays

A ChoiceFormat defining n intervals (n >= 2) is specified by three arrays of n items:

Formatting and Parsing

During formatting, a number is converted to a string. ChoiceFormat accomplishes this by mapping the number to an interval using the following rule. Given a number X and and index value j in the range 0..n-1, where n is the number of ranges:

<blockquote>X matches j if and only if limit[j] <= X < limit[j+1] </blockquote>

(This assumes that all closures are FALSE. If some closures are TRUE then the relations must be changed to <= or < as appropriate.) If there is no match, then either the first or last index is used, depending on whether the number is too low or too high. Once a number is mapped to an interval j, the string formats[j] is output.

During parsing, a string is converted to a number. ChoiceFormat finds the element formats[j] equal to the string, and returns limits[j] as the parsed value.

Notes

The first limit value does not define a range boundary. For example, in the pattern "1.0a|2.0b", the intervals are [-Inf, 2.0) and [2.0, +Inf]. It appears that the first interval should be [1.0, 2.0). However, since all values that are too small are mapped to range zero, the first interval is effectively [-Inf, 2.0). However, the first limit value is used during formatting. In this example, parse("a") returns 1.0.

There are no gaps between intervals and the entire number line is covered. A ChoiceFormat maps all possible double values to a finite set of intervals.

The non-number NaN is mapped to interval zero during formatting.

Examples

Here is an example of two arrays that map the number 1..7 to the English day of the week abbreviations Sun..Sat. No closures array is given; this is the same as specifying all closures to be FALSE.

    {1,2,3,4,5,6,7},
     {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}

Here is an example that maps the ranges [-Inf, 1), [1, 1], and (1, +Inf] to three strings. That is, the number line is split into three ranges: x < 1.0, x = 1.0, and x > 1.0.

    {0, 1, 1},
     {FALSE, FALSE, TRUE},
     {"no files", "one file", "many files"}

Here is a simple example that shows formatting and parsing:

   #include &lt;unicode/choicfmt.h&gt;
   #include &lt;unicode/unistr.h&gt;
   #include &lt;iostream.h&gt;
   
   int main(int argc, char *argv[]) {
       double limits[] = {1,2,3,4,5,6,7};
       UnicodeString monthNames[] = {
           &quot;Sun&quot;,&quot;Mon&quot;,&quot;Tue&quot;,&quot;Wed&quot;,&quot;Thu&quot;,&quot;Fri&quot;,&quot;Sat&quot;};
       ChoiceFormat fmt(limits, monthNames, 7);
       UnicodeString str;
       char buf[256];
       for (double x = 1.0; x &lt;= 8.0; x += 1.0) {
           fmt.format(x, str);
           str.extract(0, str.length(), buf, 256, &quot;&quot;);
           str.truncate(0);
           cout &lt;&lt; x &lt;&lt; &quot; -&gt; &quot;
                &lt;&lt; buf &lt;&lt; endl;
       }
       cout &lt;&lt; endl;
       return 0;
   }

Here is a more complex example using a ChoiceFormat constructed from a pattern together with a MessageFormat.

   #include &lt;unicode/choicfmt.h&gt;
   #include &lt;unicode/msgfmt.h&gt;
   #include &lt;unicode/unistr.h&gt;
   #include &lt;iostream.h&gt;
 
   int main(int argc, char *argv[]) {
       UErrorCode status = U_ZERO_ERROR;
       double filelimits[] = {0,1,2};
       UnicodeString filepart[] =
           {&quot;are no files&quot;,&quot;is one file&quot;,&quot;are {0} files&quot;};
       ChoiceFormat* fileform = new ChoiceFormat(filelimits, filepart, 3 );
       Format* testFormats[] =
           {fileform, NULL, NumberFormat::createInstance(status)};
       MessageFormat pattform(&quot;There {0} on {1}&quot;, status );
       pattform.adoptFormats(testFormats, 3);
       Formattable testArgs[] = {0L, &quot;Disk A&quot;};
       FieldPosition fp(0);
       UnicodeString str;
       char buf[256];
       for (int32_t i = 0; i &lt; 4; ++i) {
           Formattable fInt(i);
           testArgs[0] = fInt;
           pattform.format(testArgs, 2, str, fp, status );
           str.extract(0, str.length(), buf, &quot;&quot;);
           str.truncate(0);
           cout &lt;&lt; &quot;Output for i=&quot; &lt;&lt; i &lt;&lt; &quot; : &quot; &lt;&lt; buf &lt;&lt; endl;
       }
       cout &lt;&lt; endl;
       return 0;
   }


Constructor & Destructor Documentation

ChoiceFormat::ChoiceFormat const UnicodeString newPattern,
UErrorCode status
 

Construct a new ChoiceFormat with the limits and the corresponding formats based on the pattern.

Parameters:
pattern Pattern used to construct object.
status Output param to receive success code. If the pattern cannot be parsed, set to failure code.

ChoiceFormat::ChoiceFormat const double *  limits,
const UnicodeString formats,
int32_t  count
 

Construct a new ChoiceFormat with the given limits and formats.

Copy the limits and formats instead of adopting them.

Parameters:
limits Array of limit values.
formats Array of formats.
count Size of 'limits' and 'formats' arrays.

ChoiceFormat::ChoiceFormat const double *  limits,
const UBool *  closures,
const UnicodeString formats,
int32_t  count
 

Construct a new ChoiceFormat with the given limits and formats.

Copy the limits and formats (instead of adopting them). By default, each limit in the array specifies the inclusive lower bound of its range, and the exclusive upper bound of the previous range. However, if the isLimitOpen element corresponding to a limit is TRUE, then the limit is the exclusive lower bound of its range, and the inclusive upper bound of the previous range.

Parameters:
limits Array of limit values
closures Array of booleans specifying whether each element of 'limits' is open or closed. If FALSE, then the corresponding limit is a member of the range above it. If TRUE, then the limit belongs to the range below it.
formats Array of formats
count Size of 'limits', 'closures', and 'formats' arrays

ChoiceFormat::ChoiceFormat const ChoiceFormat  ) 
 

Copy constructor.

virtual ChoiceFormat::~ChoiceFormat  )  [virtual]
 

Destructor.


Member Function Documentation

virtual void ChoiceFormat::adoptChoices double *  limitsToAdopt,
UBool *  closuresToAdopt,
UnicodeString formatsToAdopt,
int32_t  count
[virtual]
 

Set the choices to be used in formatting.

The arrays are adopted and should not be deleted by the caller. See class description for documenatation of the limits, closures, and formats arrays.

Parameters:
limitsToAdopt Array of limits to adopt
closuresToAdopt Array of limit booleans to adopt
formatsToAdopt Array of format string to adopt
count The size of the above arrays
Deprecated:
Remove after 2003-mar-25.
Use setChoices instead.

virtual void ChoiceFormat::adoptChoices double *  limitsToAdopt,
UnicodeString formatsToAdopt,
int32_t  count
[virtual]
 

Set the choices to be used in formatting.

The arrays are adopted and should not be deleted by the caller.

Parameters:
limitsToAdopt Contains the top value that you want parsed with that format,and should be in ascending sorted order. When formatting X, the choice will be the i, where limit[i] <= X < limit[i+1].
formatsToAdopt The format strings you want to use for each limit.
count The size of the above arrays.
Deprecated:
Remove after 2003-mar-25.
Use setChoices instead.

virtual void ChoiceFormat::applyPattern const UnicodeString pattern,
UParseError parseError,
UErrorCode status
[virtual]
 

Sets the pattern.

Parameters:
pattern The pattern to be applied.
parseError Struct to recieve information on position of error if an error is encountered
status Output param set to success/failure code on exit. If the pattern is invalid, this will be set to a failure result.

virtual void ChoiceFormat::applyPattern const UnicodeString pattern,
UErrorCode status
[virtual]
 

Sets the pattern.

Parameters:
pattern The pattern to be applied.
status Output param set to success/failure code on exit. If the pattern is invalid, this will be set to a failure result.

virtual Format* ChoiceFormat::clone void   )  const [virtual]
 

Clone this Format object polymorphically.

The caller owns the result and should delete it when done.

Implements Format.

UnicodeString & ChoiceFormat::format int32_t  number,
UnicodeString output
const [inline]
 

Redeclared NumberFormat method.

Reimplemented from NumberFormat.

UnicodeString & ChoiceFormat::format double  number,
UnicodeString output
const [inline]
 

Redeclared NumberFormat method.

Reimplemented from NumberFormat.

UnicodeString & ChoiceFormat::format const Formattable obj,
UnicodeString result,
UErrorCode status
const [inline]
 

Redeclared NumberFormat method.

Reimplemented from NumberFormat.

virtual UnicodeString& ChoiceFormat::format const Formattable obj,
UnicodeString toAppendTo,
FieldPosition pos,
UErrorCode status
const [virtual]
 

Format an object using this object's choices.

Reimplemented from NumberFormat.

virtual UnicodeString& ChoiceFormat::format const Formattable objs,
int32_t  cnt,
UnicodeString toAppendTo,
FieldPosition pos,
UErrorCode success
const [virtual]
 

Format an array of objects using this object's choices.

virtual UnicodeString& ChoiceFormat::format int32_t  number,
UnicodeString toAppendTo,
FieldPosition pos
const [virtual]
 

Format a int_32t number using this object's choices.

Implements NumberFormat.

virtual UnicodeString& ChoiceFormat::format double  number,
UnicodeString toAppendTo,
FieldPosition pos
const [virtual]
 

Format a double or long number using this object's choices.

Parameters:
number The value to be formatted.
toAppendTo The string to append the formatted string to. This is an output parameter.
pos On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns:
A reference to 'toAppendTo'.

Implements NumberFormat.

virtual const UBool* ChoiceFormat::getClosures int32_t &  count  )  const [virtual]
 

Get the limit booleans passed in the constructor.

The caller must not delete the result.

Returns:
the closures

UClassID ChoiceFormat::getDynamicClassID void   )  const [inline, virtual]
 

Returns a unique class ID POLYMORPHICALLY.

Pure virtual override. This method is to implement a simple version of RTTI, since not all C++ compilers support genuine RTTI. Polymorphic operator==() and clone() methods call this method.

Returns:
The class ID for this object. All objects of a given class have the same class ID. Objects of other classes have different class IDs.

Reimplemented from NumberFormat.

virtual const UnicodeString* ChoiceFormat::getFormats int32_t &  count  )  const [virtual]
 

Get the formats passed in the constructor.

Returns:
the formats.

virtual const double* ChoiceFormat::getLimits int32_t &  count  )  const [virtual]
 

Get the limits passed in the constructor.

Returns:
the limits.

static UClassID ChoiceFormat::getStaticClassID void   )  [inline, static]
 

Return the class ID for this class.

This is useful only for comparing to a return value from getDynamicClassID(). For example:

 .       Base* polymorphic_pointer = createPolymorphicObject();
 .       if (polymorphic_pointer->getDynamicClassID() ==
 .           Derived::getStaticClassID()) ...
 
Returns:
The class ID for all objects of this class.

Reimplemented from NumberFormat.

double ChoiceFormat::nextDouble double  d  )  [inline, static]
 

Finds the least double greater than d.

If NaN, returns same value. Used to make half-open intervals.

See also:
ChoiceFormat::previousDouble
Deprecated:
This will be removed after 2002-Jun-30.
Use closures API instead.

const ChoiceFormat& ChoiceFormat::operator= const ChoiceFormat  ) 
 

Assignment operator.

virtual UBool ChoiceFormat::operator== const Format other  )  const [virtual]
 

Return true if the given Format objects are semantically equal.

Objects of different subclasses are considered unequal.

Reimplemented from NumberFormat.

virtual void ChoiceFormat::parse const UnicodeString text,
Formattable result,
UErrorCode status
const [virtual]
 

Parse a string as a numeric value, and return a Formattable numeric object.

This method parses integers only if IntegerOnly is set.

Parameters:
text The text to be parsed.
result Formattable to be set to the parse result. If parse fails, return contents are undefined.
status Success or failure output parameter.
Returns:
A Formattable object of numeric type. The caller owns this an must delete it. NULL on failure.
See also:
NumberFormat::isParseIntegerOnly

Reimplemented from NumberFormat.

virtual void ChoiceFormat::parse const UnicodeString text,
Formattable result,
ParsePosition parsePosition
const [virtual]
 

Return a long if possible (e.g.

within range LONG_MAX, LONG_MAX], and with no decimals), otherwise a double. If IntegerOnly is set, will stop at a decimal point (or equivalent; e.g. for rational numbers "1 2/3", will stop after the 1).

If no object can be parsed, parsePosition is unchanged, and NULL is returned.

Parameters:
text The text to be parsed.
result Formattable to be set to the parse result. If parse fails, return contents are undefined.
parsePosition The position to start parsing at on input. On output, moved to after the last successfully parse character. On parse failure, does not change.
Returns:
A Formattable object of numeric type. The caller owns this an must delete it. NULL on failure.
See also:
NumberFormat::isParseIntegerOnly

Implements NumberFormat.

double ChoiceFormat::previousDouble double  d  )  [inline, static]
 

Finds the greatest double less than d.

If NaN, returns same value.

See also:
ChoiceFormat::nextDouble
Deprecated:
This will be removed after 2002-Jun-30.
Use closures API instead.

virtual void ChoiceFormat::setChoices const double *  limits,
const UBool *  closures,
const UnicodeString formats,
int32_t  count
[virtual]
 

Set the choices to be used in formatting.

See class description for documenatation of the limits, closures, and formats arrays.

Parameters:
limits Array of limits
closures Array of limit booleans
formats Array of format string
count The size of the above arrays

virtual void ChoiceFormat::setChoices const double *  limitsToCopy,
const UnicodeString formatsToCopy,
int32_t  count
[virtual]
 

Set the choices to be used in formatting.

Parameters:
limitsToCopy Contains the top value that you want parsed with that format,and should be in ascending sorted order. When formatting X, the choice will be the i, where limit[i] <= X < limit[i+1].
formatsToCopy The format strings you want to use for each limit.
count The size of the above arrays.

virtual UnicodeString& ChoiceFormat::toPattern UnicodeString pattern  )  const [virtual]
 

Gets the pattern.


The documentation for this class was generated from the following file:
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