Added in API level 1

Summary: Inherited Constants | Ctors | Methods | Inherited Methods

ChoiceFormat

public class ChoiceFormat
extends NumberFormat

java.lang.Object
↳	java.text.Format
	↳	java.text.NumberFormat
		↳	java.text.ChoiceFormat

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. If the limit array is not in ascending order, the results of formatting will be incorrect. ChoiceFormat also accepts \u221E as equivalent to infinity(INF).

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,

limits = {1,2,3,4,5,6,7}
formats = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}
limits = {0, 1, ChoiceFormat.nextDouble(1)}
formats = {"no files", "one file", "many files"}
(nextDouble can be used to get the next higher double, to make the half-open interval.)

Here is a simple example that shows formatting and parsing:

double[] limits = {1,2,3,4,5,6,7};
 String[] dayOfWeekNames = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"};
 ChoiceFormat form = new ChoiceFormat(limits, dayOfWeekNames);
 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));
 }

Specifying a pattern for ChoiceFormat objects is fairly straightforward. For example:

ChoiceFormat fmt = new ChoiceFormat(
      "-1#is negative| 0#is zero or fraction | 1#is one |1.0<is 1+ |2#is two |2<is more than 2.");
 System.out.println("Formatter Pattern : " + fmt.toPattern());

 System.out.println("Format with -INF : " + fmt.format(Double.NEGATIVE_INFINITY));
 System.out.println("Format with -1.0 : " + fmt.format(-1.0));
 System.out.println("Format with 0 : " + fmt.format(0));
 System.out.println("Format with 0.9 : " + fmt.format(0.9));
 System.out.println("Format with 1.0 : " + fmt.format(1));
 System.out.println("Format with 1.5 : " + fmt.format(1.5));
 System.out.println("Format with 2 : " + fmt.format(2));
 System.out.println("Format with 2.1 : " + fmt.format(2.1));
 System.out.println("Format with NaN : " + fmt.format(Double.NaN));
 System.out.println("Format with +INF : " + fmt.format(Double.POSITIVE_INFINITY));

And the output result would be like the following:

Format with -INF : is negative
 Format with -1.0 : is negative
 Format with 0 : is zero or fraction
 Format with 0.9 : is zero or fraction
 Format with 1.0 : is one
 Format with 1.5 : is 1+
 Format with 2 : is two
 Format with 2.1 : is more than 2.
 Format with NaN : is negative
 Format with +INF : is more than 2.

Synchronization

Choice formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.

See also:

DecimalFormat
MessageFormat

Summary

Inherited constants

From class java.text.NumberFormat

`int`	`FRACTION_FIELD` Field constant used to construct a FieldPosition object.
`int`	`INTEGER_FIELD` Field constant used to construct a FieldPosition object.

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

Public methods
`void`	`applyPattern(String newPattern)` Sets the pattern.
`Object`	`clone()` Overrides Cloneable
`boolean`	`equals(Object obj)` Equality comparison between two
`StringBuffer`	`format(double number, StringBuffer toAppendTo, FieldPosition status)` Returns pattern with formatted double.
`StringBuffer`	`format(long number, StringBuffer toAppendTo, FieldPosition status)` Specialization of format.
`Object[]`	`getFormats()`
`double[]`	`getLimits()`
`int`	`hashCode()` Generates a hash code for the message format object.
`static final double`	`nextDouble(double d)` Finds the least double greater than `d`.
`static double`	`nextDouble(double d, boolean positive)` Finds the least double greater than `d` (if `positive` is `true`), or the greatest double less than `d` (if `positive` is `false`).
`Number`	`parse(String text, ParsePosition status)` Parses a Number from the input text.
`static final 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.

Inherited methods

From class


        
          java.text.NumberFormat

`Object`	`clone()` Overrides Cloneable.
`boolean`	`equals(Object obj)` Overrides equals.
`StringBuffer`	`format(Object number, StringBuffer toAppendTo, FieldPosition pos)` Formats a number and appends the resulting text to the given string buffer.
`final String`	`format(double number)` Specialization of format.
`abstract StringBuffer`	`format(double number, StringBuffer toAppendTo, FieldPosition pos)` Specialization of format.
`final String`	`format(long number)` Specialization of format.
`abstract StringBuffer`	`format(long number, StringBuffer toAppendTo, FieldPosition pos)` Specialization of format.
`static Locale[]`	`getAvailableLocales()` Returns a scientific format for the current default locale.
`Currency`	`getCurrency()` Gets the currency used by this number format when formatting currency values.
`static NumberFormat`	`getCurrencyInstance(Locale inLocale)` Returns a currency format for the specified locale.
`static final NumberFormat`	`getCurrencyInstance()` Returns a currency format for the current default `FORMAT` locale.
`static final NumberFormat`	`getInstance()` Returns a general-purpose number format for the current default `FORMAT` locale.
`static NumberFormat`	`getInstance(Locale inLocale)` Returns a general-purpose number format for the specified locale.
`static final NumberFormat`	`getIntegerInstance()` Returns an integer number format for the current default `FORMAT` locale.
`static NumberFormat`	`getIntegerInstance(Locale inLocale)` Returns an integer number format for the specified locale.
`int`	`getMaximumFractionDigits()` Returns the maximum number of digits allowed in the fraction portion of a number.
`int`	`getMaximumIntegerDigits()` Returns the maximum number of digits allowed in the integer portion of a number.
`int`	`getMinimumFractionDigits()` Returns the minimum number of digits allowed in the fraction portion of a number.
`int`	`getMinimumIntegerDigits()` Returns the minimum number of digits allowed in the integer portion of a number.
`static final NumberFormat`	`getNumberInstance()` Returns a general-purpose number format for the current default `FORMAT` locale.
`static NumberFormat`	`getNumberInstance(Locale inLocale)` Returns a general-purpose number format for the specified locale.
`static NumberFormat`	`getPercentInstance(Locale inLocale)` Returns a percentage format for the specified locale.
`static final NumberFormat`	`getPercentInstance()` Returns a percentage format for the current default `FORMAT` locale.
`RoundingMode`	`getRoundingMode()` Gets the `RoundingMode` used in this NumberFormat.
`int`	`hashCode()` Overrides hashCode.
`boolean`	`isGroupingUsed()` Returns true if grouping is used in this format.
`boolean`	`isParseIntegerOnly()` Returns true if this format will parse numbers as integers only.
`Number`	`parse(String source)` Parses text from the beginning of the given string to produce a number.
`abstract Number`	`parse(String source, ParsePosition parsePosition)` Returns a Long if possible (e.g., within the range [Long.MIN_VALUE, Long.MAX_VALUE] and with no decimals), otherwise a Double.
`final Object`	`parseObject(String source, ParsePosition pos)` Parses text from a string to produce a `Number`.
`void`	`setCurrency(Currency currency)` Sets the currency used by this number format when formatting currency values.
`void`	`setGroupingUsed(boolean newValue)` Set whether or not grouping will be used in this format.
`void`	`setMaximumFractionDigits(int newValue)` Sets the maximum number of digits allowed in the fraction portion of a number.
`void`	`setMaximumIntegerDigits(int newValue)` Sets the maximum number of digits allowed in the integer portion of a number.
`void`	`setMinimumFractionDigits(int newValue)` Sets the minimum number of digits allowed in the fraction portion of a number.
`void`	`setMinimumIntegerDigits(int newValue)` Sets the minimum number of digits allowed in the integer portion of a number.
`void`	`setParseIntegerOnly(boolean value)` Sets whether or not numbers should be parsed as integers only.
`void`	`setRoundingMode(RoundingMode roundingMode)` Sets the `RoundingMode` used in this NumberFormat.

From class


        
          java.text.Format

`Object`	`clone()` Creates and returns a copy of this object.
`final String`	`format(Object obj)` Formats an object to produce a string.
`abstract StringBuffer`	`format(Object obj, StringBuffer toAppendTo, FieldPosition pos)` Formats an object and appends the resulting text to a given string buffer.
`AttributedCharacterIterator`	`formatToCharacterIterator(Object obj)` Formats an Object producing an `AttributedCharacterIterator`.
`Object`	`parseObject(String source)` Parses text from the beginning of the given string to produce an object.
`abstract Object`	`parseObject(String source, ParsePosition pos)` Parses text from a string to produce an object.

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

ChoiceFormat

Added in API level 1

public ChoiceFormat (double[] limits, 
                String[] formats)

Constructs with the limits and the corresponding formats.

Parameters
`limits`	`double`: limits in ascending order
`formats`	`String`: corresponding format strings

Throws
`NullPointerException`	if `limits` or `formats` is `null`

See also:

setChoices(double, String)

ChoiceFormat

Added in API level 1

public ChoiceFormat (String newPattern)

Constructs with limits and corresponding formats based on the pattern.

Parameters
`newPattern`	`String`: the new pattern string

Throws
`NullPointerException`	if `newPattern` is `null`

See also:

applyPattern(String)

Public methods

applyPattern

Added in API level 1

public void applyPattern (String newPattern)

Sets the pattern.

Parameters
`newPattern`	`String`: See the class description.

Throws
`NullPointerException`	if `newPattern` is `null`

clone

Added in API level 1

public Object clone ()

Overrides Cloneable

Returns
`Object`	a clone of this instance.

equals

Added in API level 1

public boolean equals (Object obj)

Equality comparison between two

Parameters
`obj`	`Object`: the reference object with which to compare.

Returns
`boolean`	`true` if this object is the same as the obj argument; `false` otherwise.

format

Added in API level 1

public StringBuffer format (double number, 
                StringBuffer toAppendTo, 
                FieldPosition status)

Returns pattern with formatted double.

Parameters
`number`	`double`: number to be formatted and substituted.
`toAppendTo`	`StringBuffer`: where text is appended.
`status`	`FieldPosition`: ignore no useful status is returned.

Returns
`StringBuffer`	the formatted StringBuffer

Throws
`NullPointerException`	if `toAppendTo` is `null`

format

Added in API level 1

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.

Parameters
`number`	`long`: the long number to format
`toAppendTo`	`StringBuffer`: the StringBuffer to which the formatted text is to be appended
`status`	`FieldPosition`: keeps track on the position of the field within the returned string. For example, for formatting a number `123456789` in `Locale.US` locale, if the given `fieldPosition` is `NumberFormat.INTEGER_FIELD`, the begin index and end index of `fieldPosition` will be set to 0 and 11, respectively for the output string `123,456,789`.

Returns
`StringBuffer`	the formatted StringBuffer

getFormats

Added in API level 1

public Object[] getFormats ()

Returns
`Object[]`	a copy of the `String[]` array supplied to the constructor or the most recent call to `setChoices(double[], java.lang.String[])`.

getLimits

Added in API level 1

public double[] getLimits ()

Returns
`double[]`	a copy of the `double[]` array supplied to the constructor or the most recent call to `setChoices(double[], java.lang.String[])`.

hashCode

Added in API level 1

public int hashCode ()

Generates a hash code for the message format object.

Returns
`int`	a hash code value for this object.

nextDouble

Added in API level 1

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.

Implementation Note:

This is equivalent to calling Math.nextUp(d)

Parameters
`d`	`double`: the reference value

Returns
`double`	the least double value greather than `d`

See also:

previousDouble(double)

nextDouble

Added in API level 1

public static double nextDouble (double d, 
                boolean positive)

Finds the least double greater than d (if positive is true), or the greatest double less than d (if positive is false). If NaN, returns same value.

Implementation Note:

This is equivalent to calling positive ? Math.nextUp(d) : Math.nextDown(d)

Parameters
`d`	`double`: the reference value
`positive`	`boolean`: `true` if the least double is desired; `false` otherwise

Returns
`double`	the least or greater double value

parse

Added in API level 1

public Number parse (String text, 
                ParsePosition status)

Parses a Number from the input text.

Parameters

Parameters
`text`	`String`: the source text.
`status`	`ParsePosition`: an input-output parameter. On input, the status.index field indicates the first character of the source text that should be parsed. On exit, if no error occurred, status.index is set to the first unparsed character in the source text. On exit, if an error did occur, status.index is unchanged and status.errorIndex is set to the first index of the character that caused the parse to fail.

text

String: the source text.

status

ParsePosition: an input-output parameter. On input, the status.index field indicates the first character of the source text that should be parsed. On exit, if no error occurred, status.index is set to the first unparsed character in the source text. On exit, if an error did occur, status.index is unchanged and status.errorIndex is set to the first index of the character that caused the parse to fail.

Returns
`Number`	A Number representing the value of the number parsed.

Throws
`NullPointerException`	if `status` is `null` or if `text` is `null` and the list of choice strings is not empty.

previousDouble

Added in API level 1

public static final double previousDouble (double d)

Finds the greatest double less than d. If NaN, returns same value.

Implementation Note:

This is equivalent to calling Math.nextDown(d)

Parameters
`d`	`double`: the reference value

Returns
`double`	the greatest double value less than `d`

See also:

nextDouble(double)

setChoices

Added in API level 1

public void setChoices (double[] limits, 
                String[] formats)

Set the choices to be used in formatting.

Parameters
`limits`	`double`: 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]. If the limit array is not in ascending order, the results of formatting will be incorrect.
`formats`	`String`: 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.

Throws
`NullPointerException`	if `limits` or `formats` is `null`

toPattern

Added in API level 1

public String toPattern ()

Gets the pattern.

Returns
`String`	the pattern string