Package org.apache.commons.text.numbers
Enum DoubleFormat
- All Implemented Interfaces:
Serializable
,Comparable<DoubleFormat>
Enum containing standard double format types with methods to produce
configured formatter instances. This type is intended to provide a
quick and convenient way to create lightweight, thread-safe double format functions
for common format types using a builder pattern. Output can be localized by
passing a
DecimalFormatSymbols
instance to the
formatSymbols
method or by
directly calling the various other builder configuration methods, such as
digits
.
Comparison with DecimalFormat
This type provides some of the same functionality as Java's own
DecimalFormat
. However, unlike DecimalFormat
, the format
functions produced by this type are lightweight and thread-safe, making them
much easier to work with in multi-threaded environments. They also provide performance
comparable to, and in many cases faster than, DecimalFormat
.
Examples
// construct a formatter equivalent to Double.toString() DoubleFunction<String> fmt = DoubleFormat.MIXED.builder().build(); // construct a formatter equivalent to Double.toString() but using // format symbols for a specific locale DoubleFunction<String> fmt = DoubleFormat.MIXED.builder() .formatSymbols(DecimalFormatSymbols.getInstance(locale)) .build(); // construct a formatter equivalent to the DecimalFormat pattern "0.0##" DoubleFunction<String> fmt = DoubleFormat.PLAIN.builder() .minDecimalExponent(-3) .build(); // construct a formatter equivalent to the DecimalFormat pattern "#,##0.0##", // where whole number groups of thousands are separated DoubleFunction<String> fmt = DoubleFormat.PLAIN.builder() .minDecimalExponent(-3) .groupThousands(true) .build(); // construct a formatter equivalent to the DecimalFormat pattern "0.0##E0" DoubleFunction<String> fmt = DoubleFormat.SCIENTIFIC.builder() .maxPrecision(4) .alwaysIncludeExponent(true) .build() // construct a formatter equivalent to the DecimalFormat pattern "##0.0##E0", // i.e. "engineering format" DoubleFunction<String> fmt = DoubleFormat.ENGINEERING.builder() .maxPrecision(6) .alwaysIncludeExponent(true) .build()
Implementation Notes
Half-even
rounding is used in cases where the
decimal value must be rounded in order to meet the configuration requirements of the formatter
instance.
- Since:
- 1.10.0
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
Base class for standard double formatting classes.static final class
Builds configured format functions for standard double format types.private static class
Format class that uses engineering notation for all values.private static final class
Format class producing results similar toDouble.toString()
, with plain decimal notation for small numbers relatively close to zero and scientific notation otherwise.private static class
Format class that produces plain decimal strings that do not use scientific notation.private static class
Format class that uses scientific notation for all values. -
Enum Constant Summary
Enum ConstantsEnum ConstantDescriptionNumber format similar toscientific format
but adjusted so that the exponent value is always a multiple of 3, allowing easier alignment with SI prefixes.Number format that usesplain format
for small numbers andscientific format
for large numbers.Number format without exponents.Number format that uses exponents and contains a single digit to the left of the decimal point. -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final Function
<DoubleFormat.Builder, DoubleFunction<String>> Function used to construct instances for this format type. -
Constructor Summary
ConstructorsModifierConstructorDescriptionprivate
DoubleFormat
(Function<DoubleFormat.Builder, DoubleFunction<String>> factory) Constructs a new instance. -
Method Summary
Modifier and TypeMethodDescriptionbuilder()
Creates aDoubleFormat.Builder
for building formatter functions for this format type.static DoubleFormat
Returns the enum constant of this type with the specified name.static DoubleFormat[]
values()
Returns an array containing the constants of this enum type, in the order they are declared.
-
Enum Constant Details
-
PLAIN
Number format without exponents. Ex:0.0 12.401 100000.0 1450000000.0 0.0000000000123
-
SCIENTIFIC
Number format that uses exponents and contains a single digit to the left of the decimal point. Ex:0.0 1.2401E1 1.0E5 1.45E9 1.23E-11
-
ENGINEERING
Number format similar toscientific format
but adjusted so that the exponent value is always a multiple of 3, allowing easier alignment with SI prefixes. Ex:0.0 12.401 100.0E3 1.45E9 12.3E-12
-
MIXED
Number format that usesplain format
for small numbers andscientific format
for large numbers. The number thresholds can be configured through theplainFormatMinDecimalExponent
andplainFormatMaxDecimalExponent
properties. Ex:0.0 12.401 100000.0 1.45E9 1.23E-11
-
-
Field Details
-
factory
Function used to construct instances for this format type.
-
-
Constructor Details
-
DoubleFormat
Constructs a new instance.- Parameters:
factory
- function used to construct format instances
-
-
Method Details
-
values
Returns an array containing the constants of this enum type, in the order they are declared.- Returns:
- an array containing the constants of this enum type, in the order they are declared
-
valueOf
Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)- Parameters:
name
- the name of the enum constant to be returned.- Returns:
- the enum constant with the specified name
- Throws:
IllegalArgumentException
- if this enum type has no constant with the specified nameNullPointerException
- if the argument is null
-
builder
Creates aDoubleFormat.Builder
for building formatter functions for this format type.- Returns:
- builder instance
-