FieldPosition is a simple class used by Format
* and its subclasses to identify fields in formatted output. Fields are
* identified by constants, whose names typically end with _FIELD,
* defined in the various subclasses of Format. See
* ERA_FIELD and its friends in DateFormat for
* an example.
*
*
* FieldPosition keeps track of the position of the
* field within the formatted output with two indices: the index
* of the first character of the field and the index of the last
* character of the field.
*
*
* One version of the format method in the various
* Format classes requires a FieldPosition
* object as an argument. You use this format method
* to perform partial formatting or to get information about the
* formatted output (such as the position of a field).
*
*
* Below is an example of using FieldPosition to aid
* alignment of an array of formatted floating-point numbers on
* their decimal points:
*
* \code
* double doubleNum[] = {123456789.0, -12345678.9, 1234567.89, -123456.789,
* 12345.6789, -1234.56789, 123.456789, -12.3456789, 1.23456789};
* int dNumSize = (int)(sizeof(doubleNum)/sizeof(double));
*
* UErrorCode status = U_ZERO_ERROR;
* DecimalFormat* fmt = (DecimalFormat*) NumberFormat::createInstance(status);
* fmt->setDecimalSeparatorAlwaysShown(true);
*
* const int tempLen = 20;
* char temp[tempLen];
*
* for (int i=0; iformat(doubleNum[i], buf, pos), fmtText);
* for (int j=0; j
*
* The code will generate the following output:
*
* \code
* 123,456,789.000
* -12,345,678.900
* 1,234,567.880
* -123,456.789
* 12,345.678
* -1,234.567
* 123.456
* -12.345
* 1.234
* \endcode
*
*/
class U_I18N_API FieldPosition : public UObject {
public:
/**
* DONT_CARE may be specified as the field to indicate that the
* caller doesn't need to specify a field. Do not subclass.
*/
enum { DONT_CARE = -1 };
/**
* Creates a FieldPosition object with a non-specified field.
* @stable
*/
FieldPosition()
: UObject(), fField(DONT_CARE), fBeginIndex(0), fEndIndex(0) {}
/**
* Creates a FieldPosition object for the given field. Fields are
* identified by constants, whose names typically end with _FIELD,
* in the various subclasses of Format.
*
* @see NumberFormat#INTEGER_FIELD
* @see NumberFormat#FRACTION_FIELD
* @see DateFormat#YEAR_FIELD
* @see DateFormat#MONTH_FIELD
* @stable
*/
FieldPosition(int32_t field)
: UObject(), fField(field), fBeginIndex(0), fEndIndex(0) {}
/**
* Copy constructor
* @param copy the object to be copied from.
* @stable
*/
FieldPosition(const FieldPosition& copy)
: UObject(copy), fField(copy.fField), fBeginIndex(copy.fBeginIndex), fEndIndex(copy.fEndIndex) {}
/**
* Destructor
* @stable
*/
~FieldPosition() {}
/**
* Assignment operator
* @param copy the object to be copied from.
* @stable
*/
FieldPosition& operator=(const FieldPosition& copy);
/**
* Equality operator.
* @param that the object to be compared with.
* @return TRUE if the two field positions are equal, FALSE otherwise.
* @stable
*/
UBool operator==(const FieldPosition& that) const;
/**
* Equality operator.
* @param that the object to be compared with.
* @return TRUE if the two field positions are not equal, FALSE otherwise.
* @stable
*/
UBool operator!=(const FieldPosition& that) const;
/**
* Retrieve the field identifier.
* @return the field identifier.
* @stable
*/
int32_t getField(void) const { return fField; }
/**
* Retrieve the index of the first character in the requested field.
* @return the index of the first character in the requested field.
* @stable
*/
int32_t getBeginIndex(void) const { return fBeginIndex; }
/**
* Retrieve the index of the character following the last character in the
* requested field.
* @return the index of the character following the last character in the
* requested field.
* @stable
*/
int32_t getEndIndex(void) const { return fEndIndex; }
/**
* Set the field.
* @param f the new value of the field.
* @stable
*/
void setField(int32_t f) { fField = f; }
/**
* Set the begin index. For use by subclasses of Format.
* @param bi the new value of the begin index
* @stable
*/
void setBeginIndex(int32_t bi) { fBeginIndex = bi; }
/**
* Set the end index. For use by subclasses of Format.
* @param ei the new value of the end index
* @stable
*/
void setEndIndex(int32_t ei) { fEndIndex = ei; }
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @draft ICU 2.2
*/
virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); }
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @draft ICU 2.2
*/
static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
private:
/**
* Input: Desired field to determine start and end offsets for.
* The meaning depends on the subclass of Format.
*/
int32_t fField;
/**
* Output: Start offset of field in text.
* If the field does not occur in the text, 0 is returned.
*/
int32_t fBeginIndex;
/**
* Output: End offset of field in text.
* If the field does not occur in the text, 0 is returned.
*/
int32_t fEndIndex;
/**
* The address of this static class variable serves as this class's ID
* for ICU "poor man's RTTI".
*/
static const char fgClassID;
};
inline FieldPosition&
FieldPosition::operator=(const FieldPosition& copy)
{
fField = copy.fField;
fEndIndex = copy.fEndIndex;
fBeginIndex = copy.fBeginIndex;
return *this;
}
inline UBool
FieldPosition::operator==(const FieldPosition& copy) const
{
if( fField != copy.fField ||
fEndIndex != copy.fEndIndex ||
fBeginIndex != copy.fBeginIndex)
return FALSE;
else
return TRUE;
}
inline UBool
FieldPosition::operator!=(const FieldPosition& copy) const
{
return !operator==(copy);
}
U_NAMESPACE_END
#endif // _FIELDPOS
//eof