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FieldPosition Class Reference

FieldPosition is a simple class used by Format and its subclasses to identify fields in formatted output. More...

#include <fieldpos.h>

List of all members.

Public Types

enum  { DONT_CARE = -1 }
 DONT_CARE may be specified as the field to indicate that the caller doesn't need to specify a field. More...


Public Methods

 FieldPosition ()
 Creates a FieldPosition object with a non-specified field. More...

 FieldPosition (int32_t field)
 Creates a FieldPosition object for the given field. More...

 FieldPosition (const FieldPosition& copy)
 Copy constructor. More...

 ~FieldPosition ()
 Destructor. More...

FieldPosition& operator= (const FieldPosition& copy)
 Assignment operator. More...

UBool operator== (const FieldPosition& that) const
 Equality operator. More...

UBool operator!= (const FieldPosition& that) const
 Equality operator. More...

int32_t getField (void) const
 Retrieve the field identifier. More...

int32_t getBeginIndex (void) const
 Retrieve the index of the first character in the requested field. More...

int32_t getEndIndex (void) const
 Retrieve the index of the character following the last character in the requested field. More...

void setField (int32_t f)
 Set the field. More...

void setBeginIndex (int32_t bi)
 Set the begin index. More...

void setEndIndex (int32_t ei)
 Set the end index. More...


Private Attributes

int32_t fField
 Input: Desired field to determine start and end offsets for. More...

int32_t fBeginIndex
 Output: Start offset of field in text. More...

int32_t fEndIndex
 Output: End offset of field in text. More...


Detailed Description

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:

 
       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; i<dNumSize; i++) {
           FieldPosition pos(NumberFormat::INTEGER_FIELD);
           UnicodeString buf;
           char fmtText[tempLen];
           ToCharString(fmt->format(doubleNum[i], buf, pos), fmtText);
           for (int j=0; j<tempLen; j++) temp[j] = ' '; // clear with spaces
           temp[__min(tempLen, tempLen-pos.getEndIndex())] = '\0';
           cout << temp << fmtText   << endl;
       }
       delete fmt;

The code will generate the following output:

 
           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

Definition at line 92 of file fieldpos.h.


Member Enumeration Documentation

anonymous enum
 

DONT_CARE may be specified as the field to indicate that the caller doesn't need to specify a field.

Do not subclass.

Enumeration values:
DONT_CARE  

Definition at line 98 of file fieldpos.h.


Constructor & Destructor Documentation

FieldPosition::FieldPosition ( ) [inline]
 

Creates a FieldPosition object with a non-specified field.

Stable:

Definition at line 104 of file fieldpos.h.

FieldPosition::FieldPosition ( int32_t field ) [inline]
 

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 also:
NumberFormat::INTEGER_FIELD , NumberFormat::FRACTION_FIELD , DateFormat::YEAR_FIELD , DateFormat::MONTH_FIELD
Stable:

Definition at line 118 of file fieldpos.h.

FieldPosition::FieldPosition ( const FieldPosition & copy ) [inline]
 

Copy constructor.

Parameters:
copy   the object to be copied from.
Stable:

Definition at line 126 of file fieldpos.h.

FieldPosition::~FieldPosition ( ) [inline]
 

Destructor.

Stable:

Definition at line 133 of file fieldpos.h.


Member Function Documentation

int32_t FieldPosition::getBeginIndex ( void ) const [inline]
 

Retrieve the index of the first character in the requested field.

Stable:

Definition at line 165 of file fieldpos.h.

int32_t FieldPosition::getEndIndex ( void ) const [inline]
 

Retrieve the index of the character following the last character in the requested field.

Stable:

Definition at line 172 of file fieldpos.h.

int32_t FieldPosition::getField ( void ) const [inline]
 

Retrieve the field identifier.

Stable:

Definition at line 159 of file fieldpos.h.

UBool FieldPosition::operator!= ( const FieldPosition & copy ) const [inline]
 

Equality operator.

Returns:
TRUE if the two field positions are not equal, FALSE otherwise.
Stable:

Definition at line 233 of file fieldpos.h.

FieldPosition & FieldPosition::operator= ( const FieldPosition & copy ) [inline]
 

Assignment operator.

Stable:

Definition at line 213 of file fieldpos.h.

UBool FieldPosition::operator== ( const FieldPosition & copy ) const [inline]
 

Equality operator.

Returns:
TRUE if the two field positions are equal, FALSE otherwise.
Stable:

Definition at line 222 of file fieldpos.h.

Referenced by operator!=().

void FieldPosition::setBeginIndex ( int32_t bi ) [inline]
 

Set the begin index.

For use by subclasses of Format.

Stable:

Definition at line 184 of file fieldpos.h.

void FieldPosition::setEndIndex ( int32_t ei ) [inline]
 

Set the end index.

For use by subclasses of Format.

Stable:

Definition at line 190 of file fieldpos.h.

void FieldPosition::setField ( int32_t f ) [inline]
 

Set the field.

Stable:

Definition at line 178 of file fieldpos.h.


Member Data Documentation

int32_t FieldPosition::fBeginIndex [private]
 

Output: Start offset of field in text.

If the field does not occur in the text, 0 is returned.

Definition at line 203 of file fieldpos.h.

int32_t FieldPosition::fEndIndex [private]
 

Output: End offset of field in text.

If the field does not occur in the text, 0 is returned.

Definition at line 209 of file fieldpos.h.

int32_t FieldPosition::fField [private]
 

Input: Desired field to determine start and end offsets for.

The meaning depends on the subclass of Format.

Definition at line 197 of file fieldpos.h.


The documentation for this class was generated from the following file:
Generated at Tue Jun 12 14:04:30 2001 for ICU 1.8.1 by doxygen1.2.3 written by Dimitri van Heesch, © 1997-2000