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Class java.text.ChoiceFormat

java.lang.Object
    |
    +----java.text.Format
            |
            +----java.text.NumberFormat
                    |
                    +----java.text.ChoiceFormat

public class ChoiceFormat
extends NumberFormat
A ChoiceFormat allows you to attach a format to a range of numbers. It is generally used in a MessageFormat for handling plurals. The choice is specified with an ascending list of doubles, where each item specifies a half-open interval up to the next item:
 X matches j if and only if limit[j] <= X < limit[j+1]
 
If there is no match, then either the first or last index is used, depending on whether the number (X) is too low or too high.

Note: ChoiceFormat differs from the other Format classes in that you create a ChoiceFormat object with a constructor (not with a getInstance style factory method). The factory methods aren't necessary because ChoiceFormat doesn't require any complex setup for a given locale. In fact, ChoiceFormat doesn't implement any locale specific behavior.

When creating a ChoiceFormat, you must specify an array of formats and an array of limits. The length of these arrays must be the same. For example,

Here is a simple example that shows formatting and parsing:

 double[] limits = {1,2,3,4,5,6,7};
 String[] monthNames = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"};
 ChoiceFormat form = new ChoiceFormat(limits, monthNames);
 ParsePosition status = new ParsePosition(0);
 for (double i = 0.0; i <= 8.0; ++i) {
     status.setIndex(0);
     System.out.println(i + " -> " + form.format(i) + " -> "
                              + form.parse(form.format(i),status));
 }
 
Here is a more complex example, with a pattern format:
 double[] filelimits = {0,1,2};
 String[] filepart = {"are no files","is one file","are {2} files"};
 ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart);
 Format[] testFormats = {fileform, null, NumberFormat.getInstance()};
 MessageFormat pattform = new MessageFormat("There {0} on {1}");
 pattform.setFormats(testFormats);
 Object[] testArgs = {null, "ADisk", null};
 for (int i = 0; i < 4; ++i) {
     testArgs[0] = new Integer(i);
     testArgs[2] = testArgs[0];
     System.out.println(pattform.format(testArgs));
 }
 

See Also:
DecimalFormat, MessageFormat

Fields inherited from class java.text.NumberFormat
 FRACTION_FIELD, INTEGER_FIELD
 

Constructor Summary
 ChoiceFormat(String newPattern)
Constructs with limits and corresponding formats based on the pattern.
 ChoiceFormat(double[] limits, String[] formats)
Constructs with the limits and the corresponding formats.
 

Method Summary
void  applyPattern(String newPattern)
Sets the pattern.
Object  clone()
Overrides Cloneable
boolean  equals(Object obj)
Equality comparision between two
StringBuffer  format(long number, StringBuffer toAppendTo, FieldPosition status)
Specialization of format.
StringBuffer  format(double number, StringBuffer toAppendTo, FieldPosition status)
 
Object[]  getFormats()
Get the formats passed in the constructor.
double[]  getLimits()
Get the limits passed in the constructor.
int  hashCode()
Generates a hash code for the message format object.
static double  nextDouble(double d)
Finds the least double greater than d.
static double  nextDouble(double d, boolean positive)
 
Number  parse(String text, ParsePosition status)
 
static double  previousDouble(double d)
Finds the greatest double less than d.
void  setChoices(double[] limits, String[] formats)
Set the choices to be used in formatting.
String  toPattern()
Gets the pattern.
 
Methods inherited from class java.text.NumberFormat
 clone, equals, format, format, format, format, format, getAvailableLocales, getCurrencyInstance, getCurrencyInstance, getInstance, getInstance, getMaximumFractionDigits, getMaximumIntegerDigits, getMinimumFractionDigits, getMinimumIntegerDigits, getNumberInstance, getNumberInstance, getPercentInstance, getPercentInstance, hashCode, isGroupingUsed, isParseIntegerOnly, parse, parse, parseObject, setGroupingUsed, setMaximumFractionDigits, setMaximumIntegerDigits, setMinimumFractionDigits, setMinimumIntegerDigits, setParseIntegerOnly
 
Methods inherited from class java.text.Format
 clone, format, format, parseObject, parseObject
 
Methods inherited from class java.lang.Object
 clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ChoiceFormat

public ChoiceFormat(String newPattern)
Constructs with limits and corresponding formats based on the pattern.

ChoiceFormat

public ChoiceFormat(double[] limits,
                    String[] formats)
Constructs with the limits and the corresponding formats.
See Also:
setChoices
Method Detail

applyPattern

public void applyPattern(String newPattern)
Sets the pattern.
Parameters:
newPattern - See the class description.

toPattern

public String toPattern()
Gets the pattern.

setChoices

public void setChoices(double[] limits,
                       String[] formats)
Set the choices to be used in formatting.
Parameters:
limits - 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].
formats - are the formats you want to use for each limit. They can be either Format objects or Strings. When formatting with object Y, if the object is a NumberFormat, then ((NumberFormat) Y).format(X) is called. Otherwise Y.toString() is called.

getLimits

public double[] getLimits()
Get the limits passed in the constructor.
Returns:
the limits.

getFormats

public Object[] getFormats()
Get the formats passed in the constructor.
Returns:
the formats.

format

public StringBuffer format(long number,
                           StringBuffer toAppendTo,
                           FieldPosition status)
Specialization of format. This method really calls format(double, StringBuffer, FieldPosition) thus the range of longs that are supported is only equal to the range that can be stored by double. This will never be a practical limitation.
Overrides:
format in class NumberFormat

format

public StringBuffer format(double number,
                           StringBuffer toAppendTo,
                           FieldPosition status)
Overrides:
format in class NumberFormat

parse

public Number parse(String text,
                    ParsePosition status)
Overrides:
parse in class NumberFormat

nextDouble

public static final double nextDouble(double d)
Finds the least double greater than d. If NaN, returns same value.

Used to make half-open intervals.

See Also:
previousDouble

previousDouble

public static final double previousDouble(double d)
Finds the greatest double less than d. If NaN, returns same value.
See Also:
nextDouble

clone

public Object clone()
Overrides Cloneable
Overrides:
clone in class NumberFormat

hashCode

public int hashCode()
Generates a hash code for the message format object.
Overrides:
hashCode in class NumberFormat

equals

public boolean equals(Object obj)
Equality comparision between two
Overrides:
equals in class NumberFormat

nextDouble

public static double nextDouble(double d,
                                boolean positive)

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