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java.lang.Object
|
+----java.text.Format
|
+----java.text.NumberFormat
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+----java.text.ChoiceFormat
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:
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.X matches j if and only if limit[j] <= X < limit[j+1]
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,
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[] 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));
}
method ChoiceFormat(newPattern=String) public
method ChoiceFormat(limits=double[], -
formats=String[]) public
method applyPattern(newPattern=String) public
method toPattern() returns String public
method setChoices(limits=double[], -
formats=String[]) public
method getLimits() returns double[] public
method getFormats() returns Object[] public
method format(number=long, -
toAppendTo=StringBuffer, -
status=FieldPosition) returns StringBuffer public
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.
method format(number=double, -
toAppendTo=StringBuffer, -
status=FieldPosition) returns StringBuffer public
method parse(text=String, -
status=ParsePosition) returns Number public
method nextDouble(d=double) returns static double public final
Used to make half-open intervals.
method previousDouble(d=double) returns static double public final
method clone() returns Object public
method hashCode() returns int public
method equals(obj=Object) returns boolean public
method nextDouble(d=double, -
positive=boolean) returns double public static
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