#include <choicfmt.h>
Inheritance diagram for ChoiceFormat:
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 ChoiceFormat & | operator= (const ChoiceFormat &) |
Assignment operator. | |
virtual | ~ChoiceFormat () |
Destructor. | |
virtual Format * | clone (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 UnicodeString & | toPattern (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 UnicodeString * | getFormats (int32_t &count) const |
Get the formats passed in the constructor. | |
virtual UnicodeString & | format (double number, UnicodeString &toAppendTo, FieldPosition &pos) const |
Format a double or long number using this object's choices. | |
virtual UnicodeString & | format (int32_t number, UnicodeString &toAppendTo, FieldPosition &pos) const |
Format a int_32t number using this object's choices. | |
virtual UnicodeString & | format (const Formattable *objs, int32_t cnt, UnicodeString &toAppendTo, FieldPosition &pos, UErrorCode &success) const |
Format an array of objects using this object's choices. | |
virtual UnicodeString & | format (const Formattable &obj, UnicodeString &toAppendTo, FieldPosition &pos, UErrorCode &status) const |
Format an object using this object's choices. | |
UnicodeString & | format (const Formattable &obj, UnicodeString &result, UErrorCode &status) const |
Redeclared NumberFormat method. | |
UnicodeString & | format (double number, UnicodeString &output) const |
Redeclared NumberFormat method. | |
UnicodeString & | format (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 | |
UClassID | getStaticClassID (void) |
Return the class ID for this class. | |
double | nextDouble (double d, UBool positive) |
double | nextDouble (double d) |
Finds the least double greater than d. | |
double | previousDouble (double d) |
Finds the greatest double less than d. | |
Friends | |
class | MessageFormat |
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:
0#are no files|1#is 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:
#
) indicates that the lower limit given by number is inclusive. That is, the limit value belongs to this range. Another way of saying this is that the corresponding closure is FALSE
. The Unicode less than or equals sign U+2264 may be used in place of #
. <
) indicates that the lower limit given by number is exclusive. This means that the limit belongs to the prior range. Another way of saying this is that the corresponding closure is TRUE
. See below for more information about closures.
Arrays
A ChoiceFormat
defining n
intervals (n
>= 2) is specified by three arrays of n
items:
double limits[]
gives the start of each interval. This must be a non-decreasing list of values, none of which may be NaN
. UBool closures[]
determines whether each limit value is contained in the interval below it or in the interval above it. If closures[i]
is FALSE
, then limits[i]
is a member of interval i
. Otherwise it is a member of interval i+1
. If no closures array is specified, this is equivalent to having all closures be FALSE
. Closures allow one to specify half-open, open, or closed intervals. UnicodeString formats[]
gives the string label associated with each interval. 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:
X
matches j
if and only if limit[j] <= X < limit[j+1]
(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 "1.0#a|2.0#b
", 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 <unicode/choicfmt.h> #include <unicode/unistr.h> #include <iostream.h> int main(int argc, char *argv[]) { double limits[] = {1,2,3,4,5,6,7}; UnicodeString monthNames[] = { "Sun","Mon","Tue","Wed","Thu","Fri","Sat"}; ChoiceFormat fmt(limits, monthNames, 7); UnicodeString str; char buf[256]; for (double x = 1.0; x <= 8.0; x += 1.0) { fmt.format(x, str); str.extract(0, str.length(), buf, 256, ""); str.truncate(0); cout << x << " -> " << buf << endl; } cout << endl; return 0; }
Here is a more complex example using a ChoiceFormat
constructed from a pattern together with a MessageFormat
.
#include <unicode/choicfmt.h> #include <unicode/msgfmt.h> #include <unicode/unistr.h> #include <iostream.h> int main(int argc, char *argv[]) { UErrorCode status = U_ZERO_ERROR; double filelimits[] = {0,1,2}; UnicodeString filepart[] = {"are no files","is one file","are {0} files"}; ChoiceFormat* fileform = new ChoiceFormat(filelimits, filepart, 3 ); Format* testFormats[] = {fileform, NULL, NumberFormat::createInstance(status)}; MessageFormat pattform("There {0} on {1}", status ); pattform.adoptFormats(testFormats, 3); Formattable testArgs[] = {0L, "Disk A"}; FieldPosition fp(0); UnicodeString str; char buf[256]; for (int32_t i = 0; i < 4; ++i) { Formattable fInt(i); testArgs[0] = fInt; pattform.format(testArgs, 2, str, fp, status ); str.extract(0, str.length(), buf, ""); str.truncate(0); cout << "Output for i=" << i << " : " << buf << endl; } cout << endl; return 0; }
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Construct a new ChoiceFormat with the limits and the corresponding formats based on the pattern.
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Construct a new ChoiceFormat with the given limits and formats. Copy the limits and formats instead of adopting them.
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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.
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Copy constructor.
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Destructor.
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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.
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Set the choices to be used in formatting. The arrays are adopted and should not be deleted by the caller.
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Sets the pattern.
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Sets the pattern.
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Clone this Format object polymorphically. The caller owns the result and should delete it when done. Implements Format. |
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Redeclared NumberFormat method.
Reimplemented from NumberFormat. |
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Redeclared NumberFormat method.
Reimplemented from NumberFormat. |
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Redeclared NumberFormat method.
Reimplemented from NumberFormat. |
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Format an object using this object's choices.
Reimplemented from NumberFormat. |
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Format an array of objects using this object's choices.
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Format a int_32t number using this object's choices.
Implements NumberFormat. |
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Format a double or long number using this object's choices.
Implements NumberFormat. |
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Get the limit booleans passed in the constructor. The caller must not delete the result.
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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.
Reimplemented from NumberFormat. |
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Get the formats passed in the constructor.
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Get the limits passed in the constructor.
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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()) ...
Reimplemented from NumberFormat. |
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Finds the least double greater than d. If NaN, returns same value. Used to make half-open intervals.
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Assignment operator.
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Return true if the given Format objects are semantically equal. Objects of different subclasses are considered unequal. Reimplemented from NumberFormat. |
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Parse a string as a numeric value, and return a Formattable numeric object. This method parses integers only if IntegerOnly is set.
Reimplemented from NumberFormat. |
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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.
Implements NumberFormat. |
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Finds the greatest double less than d. If NaN, returns same value.
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Set the choices to be used in formatting. See class description for documenatation of the limits, closures, and formats arrays.
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Set the choices to be used in formatting.
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Gets the pattern.
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