org.apache.commons.numbers.fraction

Class Fraction

java.lang.Object

java.lang.Number

org.apache.commons.numbers.fraction.Fraction

All Implemented Interfaces:

Serializable, Comparable<Fraction>, Addition<Fraction>, Multiplication<Fraction>, NativeOperators<Fraction>

public final class Fraction
extends Number
implements Comparable<Fraction>, NativeOperators<Fraction>, Serializable

Representation of a rational number.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static Fraction	ONE A fraction representing "1".
static Fraction	ZERO A fraction representing "0".

Method Summary

Modifier and Type	Method and Description
Fraction	abs() Returns the absolute value of this fraction.
Fraction	add(Fraction fraction) Adds the value of this fraction to another, returning the result in reduced form.
Fraction	add(int i) Adds an integer to the fraction.
int	compareTo(Fraction other) Compares this object to another based on size.
Fraction	divide(Fraction fraction) Divides the value of this fraction by another.
Fraction	divide(int i) Divides the fraction by an integer.
double	doubleValue() Retrieves the double value closest to this fraction.
boolean	equals(Object other) Test for the equality of two fractions.
float	floatValue() Retrieves the float value closest to this fraction.
static Fraction	from(double value) Creates an instance.
static Fraction	from(double value, double epsilon, int maxIterations) Create a fraction given the double value and maximum error allowed.
static Fraction	from(double value, int maxDenominator) Creates an instance.
int	getDenominator()
int	getNumerator()
int	hashCode()
int	intValue() Retrieves the whole number part of the fraction.
long	longValue() Retrieves the whole number part of the fraction.
Fraction	multiply(Fraction fraction) Multiplies the value of this fraction by another, returning the result in reduced form.
Fraction	multiply(int i) Multiplies the fraction by an integer.
Fraction	negate() Computes the additive inverse of this fraction.
static Fraction	of(int num) Creates an instance.
static Fraction	of(int num, int den) Return a fraction given the numerator and denominator.
Fraction	one()
static Fraction	parse(String s) Parses a string that would be produced by toString() and instantiates the corresponding object.
Fraction	pow(int n)
Fraction	reciprocal() Computes the multiplicative inverse of this fraction.
int	signum() Retrieves the sign of this fraction.
Fraction	subtract(Fraction fraction) Subtracts the value of another fraction from the value of this one, returning the result in reduced form.
Fraction	subtract(int i) Subtracts an integer from this fraction.
String	toString()
Fraction	zero()

Methods inherited from class java.lang.Number

byteValue, shortValue

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

ONE

public static final Fraction ONE

A fraction representing "1".

ZERO

public static final Fraction ZERO

A fraction representing "0".

Method Detail

from

public static Fraction from(double value)

Creates an instance.

Parameters:

value - Value to convert to a fraction.

Returns:

a new instance.

Throws:

ArithmeticException - if the continued fraction failed to converge.

from

public static Fraction from(double value,
                            double epsilon,
                            int maxIterations)

Create a fraction given the double value and maximum error allowed.

References:

• Continued Fraction equations (11) and (22)-(26)

Parameters:

value - the double value to convert to a fraction.

epsilon - maximum error allowed. The resulting fraction is within epsilon of value, in absolute terms.

maxIterations - maximum number of convergents

Returns:

a new instance.

Throws:

ArithmeticException - if the continued fraction failed to converge.

from

public static Fraction from(double value,
                            int maxDenominator)

Creates an instance.

References:

• Continued Fraction equations (11) and (22)-(26)

Parameters:

value - the double value to convert to a fraction.

maxDenominator - The maximum allowed value for denominator

Returns:

a new instance.

Throws:

ArithmeticException - if the continued fraction failed to converge.

of

public static Fraction of(int num)

Creates an instance. The fraction is num / 1.

Parameters:

num - Numerator.

Returns:

a new instance.

of

public static Fraction of(int num,
                          int den)

Return a fraction given the numerator and denominator. The fraction is reduced to lowest terms.

Parameters:

num - Numerator.

den - Denominator.

Returns:

a new instance.

Throws:

ArithmeticException - if the denominator is zero or if integer overflow occurs.

abs

public Fraction abs()

Returns the absolute value of this fraction.

Returns:

the absolute value.

compareTo

public int compareTo(Fraction other)

Compares this object to another based on size.

Specified by:

compareTo in interface Comparable<Fraction>

Parameters:

other - Object to compare to.

Returns:

-1 if this is less than object, +1 if this is greater than object, 0 if they are equal.

doubleValue

public double doubleValue()

Retrieves the double value closest to this fraction. This calculates the fraction as numerator divided by denominator.

Specified by:

doubleValue in class Number

Returns:

the fraction as a double.

equals

public boolean equals(Object other)

Test for the equality of two fractions. If the lowest term numerator and denominators are the same for both fractions, the two fractions are considered to be equal.

Overrides:

equals in class Object

Parameters:

other - Fraction to test for equality with.

Returns:

true if the two fractions are equal, false otherwise.

floatValue

public float floatValue()

Retrieves the float value closest to this fraction. This calculates the fraction as numerator divided by denominator.

Specified by:

floatValue in class Number

Returns:

the fraction as float.

getDenominator

public int getDenominator()

Returns:

the denominator.

getNumerator

public int getNumerator()

Returns:

the numerator.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

intValue

public int intValue()

Retrieves the whole number part of the fraction.

Specified by:

intValue in class Number

Returns:

the largest int value that is not larger than this fraction.

longValue

public long longValue()

Retrieves the whole number part of the fraction.

Specified by:

longValue in class Number

Returns:

the largest long value that is not larger than this fraction.

signum

public int signum()

Retrieves the sign of this fraction.

Returns:

-1 if the value is strictly negative, 1 if it is strictly positive, 0 if it is 0.

negate

public Fraction negate()

Computes the additive inverse of this fraction.

Specified by:

negate in interface Addition<Fraction>

Returns:

the opposite.

reciprocal

public Fraction reciprocal()

Computes the multiplicative inverse of this fraction.

Specified by:

reciprocal in interface Multiplication<Fraction>

Returns:

the reciprocal.

add

public Fraction add(Fraction fraction)

Adds the value of this fraction to another, returning the result in reduced form. The algorithm follows Knuth, 4.5.1.

Specified by:

add in interface Addition<Fraction>

Parameters:

fraction - Fraction to add.

Returns:

a new instance.

Throws:

ArithmeticException - if the resulting numerator or denominator cannot be represented in an int.

add

public Fraction add(int i)

Adds an integer to the fraction.

Parameters:

i - Value to add.

Returns:

this + i.

subtract

public Fraction subtract(Fraction fraction)

Subtracts the value of another fraction from the value of this one, returning the result in reduced form.

Specified by:

subtract in interface NativeOperators<Fraction>

Parameters:

fraction - Fraction to subtract.

Returns:

a new instance.

Throws:

ArithmeticException - if the resulting numerator or denominator cannot be represented in an int.

subtract

public Fraction subtract(int i)

Subtracts an integer from this fraction.

Parameters:

i - Value to subtract.

Returns:

this - i.

multiply

public Fraction multiply(Fraction fraction)

Multiplies the value of this fraction by another, returning the result in reduced form.

Specified by:

multiply in interface Multiplication<Fraction>

Parameters:

fraction - Fraction to multiply by.

Returns:

a new instance.

Throws:

ArithmeticException - if the resulting numerator or denominator cannot be represented in an int.

multiply

public Fraction multiply(int i)

Multiplies the fraction by an integer.

Specified by:

multiply in interface NativeOperators<Fraction>

Parameters:

i - Value to multiply by.

Returns:

this * i.

divide

public Fraction divide(Fraction fraction)

Divides the value of this fraction by another.

Specified by:

divide in interface NativeOperators<Fraction>

Parameters:

fraction - Fraction to divide by.

Returns:

a new instance.

Throws:

ArithmeticException - if the fraction to divide by is zero or if the resulting numerator or denominator cannot be represented by an int.

divide

public Fraction divide(int i)

Divides the fraction by an integer.

Parameters:

i - Value to divide by.

Returns:

this * i.

pow

public Fraction pow(int n)

Specified by:

pow in interface NativeOperators<Fraction>

Parameters:

n - Power.

Returns:

thisn.

toString

public String toString()

Overrides:

toString in class Object

zero

public Fraction zero()

Specified by:

zero in interface Addition<Fraction>

one

public Fraction one()

Specified by:

one in interface Multiplication<Fraction>

parse

public static Fraction parse(String s)

Parses a string that would be produced by toString() and instantiates the corresponding object.

Parameters:

s - String representation.

Returns:

an instance.

Throws:

NumberFormatException - if the string does not conform to the specification.