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/*
*******************************************************************************
* Copyright (C) 2007-2009, International Business Machines Corporation and
* others. All Rights Reserved.
*******************************************************************************
*
* File PLURFMT.H
*
* Modification History:*
* Date Name Description
*
********************************************************************************
*/
#ifndef PLURFMT
#define PLURFMT
#include "unicode/utypes.h"
/**
* \file
* \brief C++ API: PluralFormat object
*/
#if !UCONFIG_NO_FORMATTING
#include "unicode/numfmt.h"
#include "unicode/plurrule.h"
U_NAMESPACE_BEGIN
class Hashtable;
/**
* <p>
* <code>PluralFormat</code> supports the creation of internationalized
* messages with plural inflection. It is based on <i>plural
* selection</i>, i.e. the caller specifies messages for each
* plural case that can appear in the users language and the
* <code>PluralFormat</code> selects the appropriate message based on
* the number.
* </p>
* <h4>The Problem of Plural Forms in Internationalized Messages</h4>
* <p>
* Different languages have different ways to inflect
* plurals. Creating internationalized messages that include plural
* forms is only feasible when the framework is able to handle plural
* forms of <i>all</i> languages correctly. <code>ChoiceFormat</code>
* doesn't handle this well, because it attaches a number interval to
* each message and selects the message whose interval contains a
* given number. This can only handle a finite number of
* intervals. But in some languages, like Polish, one plural case
* applies to infinitely many intervals (e.g., paucal applies to
* numbers ending with 2, 3, or 4 except those ending with 12, 13, or
* 14). Thus <code>ChoiceFormat</code> is not adequate.
* </p><p>
* <code>PluralFormat</code> deals with this by breaking the problem
* into two parts:
* <ul>
* <li>It uses <code>PluralRules</code> that can define more complex
* conditions for a plural case than just a single interval. These plural
* rules define both what plural cases exist in a language, and to
* which numbers these cases apply.
* <li>It provides predefined plural rules for many locales. Thus, the programmer
* need not worry about the plural cases of a language. On the flip side,
* the localizer does not have to specify the plural cases; he can simply
* use the predefined keywords. The whole plural formatting of messages can
* be done using localized patterns from resource bundles.
* </ul>
* </p>
* <h4>Usage of <code>PluralFormat</code></h4>
* <p>
* This discussion assumes that you use <code>PluralFormat</code> with
* a predefined set of plural rules. You can create one using one of
* the constructors that takes a <code>locale</code> object. To
* specify the message pattern, you can either pass it to the
* constructor or set it explicitly using the
* <code>applyPattern()</code> method. The <code>format()</code>
* method takes a number object and selects the message of the
* matching plural case. This message will be returned.
* </p>
* <h5>Patterns and Their Interpretation</h5>
* <p>
* The pattern text defines the message output for each plural case of the
* used locale. The pattern is a sequence of
* <code><i>caseKeyword</i>{<i>message</i>}</code> clauses, separated by white
* space characters. Each clause assigns the message <code><i>message</i></code>
* to the plural case identified by <code><i>caseKeyword</i></code>.
* </p><p>
* You always have to define a message text for the default plural case
* "<code>other</code>" which is contained in every rule set. If the plural
* rules of the <code>PluralFormat</code> object do not contain a plural case
* identified by <code><i>caseKeyword</i></code>, U_DEFAULT_KEYWORD_MISSING
* will be set to status.
* If you do not specify a message text for a particular plural case, the
* message text of the plural case "<code>other</code>" gets assigned to this
* plural case. If you specify more than one message for the same plural case,
* U_DUPLICATE_KEYWORD will be set to status.
* <br/>
* Spaces between <code><i>caseKeyword</i></code> and
* <code><i>message</i></code> will be ignored; spaces within
* <code><i>message</i></code> will be preserved.
* </p><p>
* The message text for a particular plural case may contain other message
* format patterns. <code>PluralFormat</code> preserves these so that you
* can use the strings produced by <code>PluralFormat</code> with other
* formatters. If you are using <code>PluralFormat</code> inside a
* <code>MessageFormat</code> pattern, <code>MessageFormat</code> will
* automatically evaluate the resulting format pattern.<br/>
* Thus, curly braces (<code>{</code>, <code>}</code>) are <i>only</i> allowed
* in message texts to define a nested format pattern.<br/>
* The pound sign (<code>#</code>) will be interpreted as the number placeholder
* in the message text, if it is not contained in curly braces (to preserve
* <code>NumberFormat</code> patterns). <code>PluralFormat</code> will
* replace each of those pound signs by the number passed to the
* <code>format()</code> method. It will be formatted using a
* <code>NumberFormat</code> for the <code>PluralFormat</code>'s locale. If you
* need special number formatting, you have to explicitly specify a
* <code>NumberFormat</code> for the <code>PluralFormat</code> to use.
* </p>
* Example
* <pre>
* UErrorCode status = U_ZERO_ERROR;
* MessageFormat* msgFmt = new MessageFormat(UnicodeString("{0, plural,
* one{{0, number, C''est #,##0.0# fichier}} other {Ce sont # fichiers}} dans la liste."),
* Locale("fr"), status);
* if (U_FAILURE(status)) {
* return;
* }
* Formattable args1[] = {(int32_t)0};
* Formattable args2[] = {(int32_t)3};
* FieldPosition ignore(FieldPosition::DONT_CARE);
* UnicodeString result;
* msgFmt->format(args1, 1, result, ignore, status);
* cout << result << endl;
* result.remove();
* msgFmt->format(args2, 1, result, ignore, status);
* cout << result << endl;
* </pre>
* Produces the output:<br/>
* <code>C'est 0,0 fichier dans la liste.</code><br/>
* <code>Ce sont 3 fichiers dans la liste."</code>
* <p>
* <strong>Note:</strong><br/>
* Currently <code>PluralFormat</code>
* does not make use of quotes like <code>MessageFormat</code>.
* If you use plural format strings with <code>MessageFormat</code> and want
* to use a quote sign "<code>'</code>", you have to write "<code>''</code>".
* <code>MessageFormat</code> unquotes this pattern and passes the unquoted
* pattern to <code>PluralFormat</code>. It's a bit trickier if you use
* nested formats that do quoting. In the example above, we wanted to insert
* "<code>'</code>" in the number format pattern. Since
* <code>NumberFormat</code> supports quotes, we had to insert
* "<code>''</code>". But since <code>MessageFormat</code> unquotes the
* pattern before it gets passed to <code>PluralFormat</code>, we have to
* double these quotes, i.e. write "<code>''''</code>".
* </p>
* <h4>Defining Custom Plural Rules</h4>
* <p>If you need to use <code>PluralFormat</code> with custom rules, you can
* create a <code>PluralRules</code> object and pass it to
* <code>PluralFormat</code>'s constructor. If you also specify a locale in this
* constructor, this locale will be used to format the number in the message
* texts.
* </p><p>
* For more information about <code>PluralRules</code>, see
* {@link PluralRules}.
* </p>
*
* ported from Java
* @stable ICU 4.0
*/
class U_I18N_API PluralFormat : public Format {
public:
/**
* Creates a new <code>PluralFormat</code> for the default locale.
* This locale will be used to get the set of plural rules and for standard
* number formatting.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given locale.
* @param locale the <code>PluralFormat</code> will be configured with
* rules for this locale. This locale will also be used for
* standard number formatting.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const Locale& locale, UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given set of rules.
* The standard number formatting will be done using the default locale.
* @param rules defines the behavior of the <code>PluralFormat</code>
* object.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const PluralRules& rules, UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given set of rules.
* The standard number formatting will be done using the given locale.
* @param locale the default number formatting will be done using this
* locale.
* @param rules defines the behavior of the <code>PluralFormat</code>
* object.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const Locale& locale, const PluralRules& rules, UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given pattern string.
* The default locale will be used to get the set of plural rules and for
* standard number formatting.
* @param pattern the pattern for this <code>PluralFormat</code>.
* errors are returned to status if the pattern is invalid.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const UnicodeString& pattern, UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given pattern string and
* locale.
* The locale will be used to get the set of plural rules and for
* standard number formatting.
* @param locale the <code>PluralFormat</code> will be configured with
* rules for this locale. This locale will also be used for
* standard number formatting.
* @param pattern the pattern for this <code>PluralFormat</code>.
* errors are returned to status if the pattern is invalid.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const Locale& locale, const UnicodeString& pattern, UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given set of rules, a
* pattern and a locale.
* @param rules defines the behavior of the <code>PluralFormat</code>
* object.
* @param pattern the pattern for this <code>PluralFormat</code>.
* errors are returned to status if the pattern is invalid.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const PluralRules& rules,
const UnicodeString& pattern,
UErrorCode& status);
/**
* Creates a new <code>PluralFormat</code> for a given set of rules, a
* pattern and a locale.
* @param locale the <code>PluralFormat</code> will be configured with
* rules for this locale. This locale will also be used for
* standard number formatting.
* @param rules defines the behavior of the <code>PluralFormat</code>
* object.
* @param pattern the pattern for this <code>PluralFormat</code>.
* errors are returned to status if the pattern is invalid.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
PluralFormat(const Locale& locale,
const PluralRules& rules,
const UnicodeString& pattern,
UErrorCode& status);
/**
* copy constructor.
* @stable ICU 4.0
*/
PluralFormat(const PluralFormat& other);
/**
* Destructor.
* @stable ICU 4.0
*/
virtual ~PluralFormat();
/**
* Sets the pattern used by this plural format.
* The method parses the pattern and creates a map of format strings
* for the plural rules.
* Patterns and their interpretation are specified in the class description.
*
* @param pattern the pattern for this plural format
* errors are returned to status if the pattern is invalid.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
void applyPattern(const UnicodeString& pattern, UErrorCode& status);
/**
* Formats a plural message for a given number.
*
* @param number a number for which the plural message should be formatted
* for. If no pattern has been applied to this
* <code>PluralFormat</code> object yet, the formatted number
* will be returned.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @return the string containing the formatted plural message.
* @stable ICU 4.0
*/
UnicodeString format(int32_t number, UErrorCode& status) const;
/**
* Formats a plural message for a given number.
*
* @param number a number for which the plural message should be formatted
* for. If no pattern has been applied to this
* PluralFormat object yet, the formatted number
* will be returned.
* @param status output param set to success or failure code on exit, which
* must not indicate a failure before the function call.
* @return the string containing the formatted plural message.
* @stable ICU 4.0
*/
UnicodeString format(double number, UErrorCode& status) const;
/**
* Formats a plural message for a given number.
*
* @param number a number for which the plural message should be formatted
* for. If no pattern has been applied to this
* <code>PluralFormat</code> object yet, the formatted number
* will be returned.
* @param appendTo output parameter to receive result.
* result is appended to existing contents.
* @param pos On input: an alignment field, if desired.
* On output: the offsets of the alignment field.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @return the string containing the formatted plural message.
* @stable ICU 4.0
*/
UnicodeString& format(int32_t number,
UnicodeString& appendTo,
FieldPosition& pos,
UErrorCode& status) const;
/**
* Formats a plural message for a given number.
*
* @param number a number for which the plural message should be formatted
* for. If no pattern has been applied to this
* <code>PluralFormat</code> object yet, the formatted number
* will be returned.
* @param appendTo output parameter to receive result.
* result is appended to existing contents.
* @param pos On input: an alignment field, if desired.
* On output: the offsets of the alignment field.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @return the string containing the formatted plural message.
* @stable ICU 4.0
*/
UnicodeString& format(double number,
UnicodeString& appendTo,
FieldPosition& pos,
UErrorCode& status) const;
/**
* Sets the locale used by this <code>PluraFormat</code> object.
* Note: Calling this method resets this <code>PluraFormat</code> object,
* i.e., a pattern that was applied previously will be removed,
* and the NumberFormat is set to the default number format for
* the locale. The resulting format behaves the same as one
* constructed from {@link #PluralFormat(const Locale& locale, UErrorCode& status)}.
* @param locale the <code>locale</code> to use to configure the formatter.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
void setLocale(const Locale& locale, UErrorCode& status);
/**
* Sets the number format used by this formatter. You only need to
* call this if you want a different number format than the default
* formatter for the locale.
* @param format the number format to use.
* @param status output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @stable ICU 4.0
*/
void setNumberFormat(const NumberFormat* format, UErrorCode& status);
/**
* Assignment operator
*
* @param other the PluralFormat object to copy from.
* @stable ICU 4.0
*/
PluralFormat& operator=(const PluralFormat& other);
/**
* Return true if another object is semantically equal to this one.
*
* @param other the PluralFormat object to be compared with.
* @return true if other is semantically equal to this.
* @stable ICU 4.0
*/
virtual UBool operator==(const Format& other) const;
/**
* Return true if another object is semantically unequal to this one.
*
* @param other the PluralFormat object to be compared with.
* @return true if other is semantically unequal to this.
* @stable ICU 4.0
*/
virtual UBool operator!=(const Format& other) const;
/**
* Clones this Format object polymorphically. The caller owns the
* result and should delete it when done.
* @stable ICU 4.0
*/
virtual Format* clone(void) const;
/**
* Redeclared Format method.
*
* @param obj The object to be formatted into a string.
* @param appendTo output parameter to receive result.
* Result is appended to existing contents.
* @param pos On input: an alignment field, if desired.
* On output: the offsets of the alignment field.
* @param status output param filled with success/failure status.
* @return Reference to 'appendTo' parameter.
* @stable ICU 4.0
*/
UnicodeString& format(const Formattable& obj,
UnicodeString& appendTo,
FieldPosition& pos,
UErrorCode& status) const;
/**
* Returns the pattern from applyPattern() or constructor().
*
* @param appendTo output parameter to receive result.
* Result is appended to existing contents.
* @return the UnicodeString with inserted pattern.
* @stable ICU 4.0
*/
UnicodeString& toPattern(UnicodeString& appendTo);
/**
* This method is not yet supported by <code>PluralFormat</code>.
* <P>
* Before calling, set parse_pos.index to the offset you want to start
* parsing at in the source. After calling, parse_pos.index is the end of
* the text you parsed. If error occurs, index is unchanged.
* <P>
* When parsing, leading whitespace is discarded (with a successful parse),
* while trailing whitespace is left as is.
* <P>
* See Format::parseObject() for more.
*
* @param source The string to be parsed into an object.
* @param result Formattable to be set to the parse result.
* If parse fails, return contents are undefined.
* @param parse_pos The position to start parsing at. Upon return
* this param is set to the position after the
* last character successfully parsed. If the
* source is not parsed successfully, this param
* will remain unchanged.
* @stable ICU 4.0
*/
virtual void parseObject(const UnicodeString& source,
Formattable& result,
ParsePosition& parse_pos) const;
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @stable ICU 4.0
*
*/
static UClassID U_EXPORT2 getStaticClassID(void);
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @stable ICU 4.0
*/
virtual UClassID getDynamicClassID() const;
private:
typedef enum fmtToken {
none,
tLetter,
tNumber,
tSpace,
tNumberSign,
tLeftBrace,
tRightBrace
}fmtToken;
Locale locale;
PluralRules* pluralRules;
UnicodeString pattern;
Hashtable *fParsedValuesHash;
NumberFormat* numberFormat;
NumberFormat* replacedNumberFormat;
PluralFormat(); // default constructor not implemented
void init(const PluralRules* rules, const Locale& curlocale, UErrorCode& status);
UBool inRange(UChar ch, fmtToken& type);
UBool checkSufficientDefinition();
void parsingFailure();
UnicodeString insertFormattedNumber(double number,
UnicodeString& message,
UnicodeString& appendTo,
FieldPosition& pos) const;
void copyHashtable(Hashtable *other, UErrorCode& status);
};
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif // _PLURFMT
//eof