- java.lang.Object
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- java.text.Format
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- java.text.NumberFormat
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- java.text.ChoiceFormat
 
 
 
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- All Implemented Interfaces:
- Serializable,- Cloneable
 
 public class ChoiceFormat extends NumberFormat AChoiceFormatallows you to attach a format to a range of numbers. It is generally used in aMessageFormatfor 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:
 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 acceptsX matches j if and only if limit[j] ≤ X < limit[j+1] \u221Eas equivalent to infinity(INF).Note: ChoiceFormatdiffers from the otherFormatclasses in that you create aChoiceFormatobject with a constructor (not with agetInstancestyle factory method). The factory methods aren't necessary becauseChoiceFormatdoesn't require any complex setup for a given locale. In fact,ChoiceFormatdoesn'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"}
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     limits = {0, 1, ChoiceFormat.nextDouble(1)}
 formats = {"no files", "one file", "many files"}
 (nextDoublecan be used to get the next higher double, to make the half-open interval.)
 Here is a simple example that shows formatting and parsing: 
 Here is a more complex example, with a pattern format: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)); }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: 
 And the output result would be like the following: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));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.SynchronizationChoice 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. - Since:
- 1.1
- See Also:
- DecimalFormat,- MessageFormat, Serialized Form
 
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Nested Class Summary- 
Nested classes/interfaces declared in class java.text.NumberFormatNumberFormat.Field
 
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Field Summary- 
Fields declared in class java.text.NumberFormatFRACTION_FIELD, INTEGER_FIELD
 
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Constructor SummaryConstructors Constructor Description 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.
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Method SummaryAll Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidapplyPattern(String newPattern)Sets the pattern.Objectclone()Overrides Cloneablebooleanequals(Object obj)Equality comparison between twoStringBufferformat(double number, StringBuffer toAppendTo, FieldPosition status)Returns pattern with formatted double.StringBufferformat(long number, StringBuffer toAppendTo, FieldPosition status)Specialization of format.Object[]getFormats()Get the formats passed in the constructor.double[]getLimits()Get the limits passed in the constructor.inthashCode()Generates a hash code for the message format object.static doublenextDouble(double d)Finds the least double greater thand.static doublenextDouble(double d, boolean positive)Finds the least double greater thand(ifpositiveistrue), or the greatest double less thand(ifpositiveisfalse).Numberparse(String text, ParsePosition status)Parses a Number from the input text.static doublepreviousDouble(double d)Finds the greatest double less thand.voidsetChoices(double[] limits, String[] formats)Set the choices to be used in formatting.StringtoPattern()Gets the pattern.- 
Methods declared in class java.text.NumberFormatformat, format, format, getAvailableLocales, getCurrency, getCurrencyInstance, getCurrencyInstance, getInstance, getInstance, getIntegerInstance, getIntegerInstance, getMaximumFractionDigits, getMaximumIntegerDigits, getMinimumFractionDigits, getMinimumIntegerDigits, getNumberInstance, getNumberInstance, getPercentInstance, getPercentInstance, getRoundingMode, isGroupingUsed, isParseIntegerOnly, parse, parseObject, setCurrency, setGroupingUsed, setMaximumFractionDigits, setMaximumIntegerDigits, setMinimumFractionDigits, setMinimumIntegerDigits, setParseIntegerOnly, setRoundingMode
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Methods declared in class java.text.Formatformat, formatToCharacterIterator, parseObject
 
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Constructor Detail- 
ChoiceFormatpublic ChoiceFormat(String newPattern) Constructs with limits and corresponding formats based on the pattern.- Parameters:
- newPattern- the new pattern string
- Throws:
- NullPointerException- if- newPatternis- null
- See Also:
- applyPattern(java.lang.String)
 
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ChoiceFormatpublic ChoiceFormat(double[] limits, String[] formats)Constructs with the limits and the corresponding formats.- Parameters:
- limits- limits in ascending order
- formats- corresponding format strings
- Throws:
- NullPointerException- if- limitsor- formatsis- null
- See Also:
- setChoices(double[], java.lang.String[])
 
 
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Method Detail- 
applyPatternpublic void applyPattern(String newPattern) Sets the pattern.- Parameters:
- newPattern- See the class description.
- Throws:
- NullPointerException- if- newPatternis- null
 
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toPatternpublic String toPattern() Gets the pattern.- Returns:
- the pattern string
 
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setChoicespublic 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]. If the limit array is not in ascending order, the results of formatting will be incorrect.
- 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.
- Throws:
- NullPointerException- if- limitsor- formatsis- null
 
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getLimitspublic double[] getLimits() Get the limits passed in the constructor.- Returns:
- the limits.
 
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getFormatspublic Object[] getFormats() Get the formats passed in the constructor.- Returns:
- the formats.
 
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formatpublic StringBuffer format(long number, StringBuffer toAppendTo, FieldPosition status) Specialization of format. This method really callsformat(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.- Specified by:
- formatin class- NumberFormat
- Parameters:
- number- the long number to format
- toAppendTo- the StringBuffer to which the formatted text is to be appended
- status- keeps track on the position of the field within the returned string. For example, for formatting a number- 123456789in- Locale.USlocale, if the given- fieldPositionis- NumberFormat.INTEGER_FIELD, the begin index and end index of- fieldPositionwill be set to 0 and 11, respectively for the output string- 123,456,789.
- Returns:
- the formatted StringBuffer
- See Also:
- Format.format(java.lang.Object)
 
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formatpublic StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition status) Returns pattern with formatted double.- Specified by:
- formatin class- NumberFormat
- Parameters:
- number- number to be formatted and substituted.
- toAppendTo- where text is appended.
- status- ignore no useful status is returned.
- Returns:
- the formatted StringBuffer
- Throws:
- NullPointerException- if- toAppendTois- null
- See Also:
- Format.format(java.lang.Object)
 
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parsepublic Number parse(String text, ParsePosition status) Parses a Number from the input text.- Specified by:
- parsein class- NumberFormat
- Parameters:
- text- the source text.
- status- 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:
- A Number representing the value of the number parsed.
- Throws:
- NullPointerException- if- statusis- nullor if- textis- nulland the list of choice strings is not empty.
- See Also:
- NumberFormat.isParseIntegerOnly(),- Format.parseObject(java.lang.String, java.text.ParsePosition)
 
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nextDoublepublic static final double nextDouble(double d) Finds the least double greater thand. IfNaN, returns same value.Used to make half-open intervals. - Parameters:
- d- the reference value
- Returns:
- the least double value greather than d
- See Also:
- previousDouble(double)
 
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previousDoublepublic static final double previousDouble(double d) Finds the greatest double less thand. IfNaN, returns same value.- Parameters:
- d- the reference value
- Returns:
- the greatest double value less than d
- See Also:
- nextDouble(double)
 
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clonepublic Object clone() Overrides Cloneable- Overrides:
- clonein class- NumberFormat
- Returns:
- a clone of this instance.
- See Also:
- Cloneable
 
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hashCodepublic int hashCode() Generates a hash code for the message format object.- Overrides:
- hashCodein class- NumberFormat
- Returns:
- a hash code value for this object.
- See Also:
- Object.equals(java.lang.Object),- System.identityHashCode(java.lang.Object)
 
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equalspublic boolean equals(Object obj) Equality comparison between two- Overrides:
- equalsin class- NumberFormat
- Parameters:
- obj- the reference object with which to compare.
- Returns:
- trueif this object is the same as the obj argument;- falseotherwise.
- See Also:
- Object.hashCode(),- HashMap
 
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nextDoublepublic static double nextDouble(double d, boolean positive)Finds the least double greater thand(ifpositiveistrue), or the greatest double less thand(ifpositiveisfalse). IfNaN, returns same value. Does not affect floating-point flags, provided these member functions do not: Double.longBitsToDouble(long) Double.doubleToLongBits(double) Double.isNaN(double)- Parameters:
- d- the reference value
- positive-- trueif the least double is desired;- falseotherwise
- Returns:
- the least or greater double value
 
 
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