Package com.landawn.abacus.util

Class Fraction

java.lang.Object
java.lang.Number
com.landawn.abacus.util.Fraction
All Implemented Interfaces:
Immutable, Serializable, Comparable<Fraction>
@Immutable public final class Fraction extends Number implements Comparable<Fraction>, Immutable

Note: it's copied from Apache Commons Lang developed at The Apache Software Foundation (http://www.apache.org/), or under the Apache License 2.0. The methods copied from other products/frameworks may be modified in this class.

Fraction is a Number implementation that stores fractions accurately.

This class is immutable, and interoperable with most methods that accept a Number.

Note that this class is intended for common use cases, it is int based and thus suffers from various overflow issues. For a BigInteger based equivalent, please see the Commons Math BigFraction class.

Since:
2.0
Version:
$Id: Fraction.java 1583482 2014-03-31 22:54:57Z niallp $
See Also:

  • Field Details

    • ZERO

      public static final Fraction ZERO
      Fraction representation of 0.

    • ONE

      public static final Fraction ONE
      Fraction representation of 1.

    • ONE_HALF

      public static final Fraction ONE_HALF
      Fraction representation of 1/2.

    • ONE_THIRD

      public static final Fraction ONE_THIRD
      Fraction representation of 1/3.

    • TWO_THIRDS

      public static final Fraction TWO_THIRDS
      Fraction representation of 2/3.

    • ONE_QUARTER

      public static final Fraction ONE_QUARTER
      Fraction representation of 1/4.

    • TWO_QUARTERS

      public static final Fraction TWO_QUARTERS
      Fraction representation of 2/4.

    • THREE_QUARTERS

      public static final Fraction THREE_QUARTERS
      Fraction representation of 3/4.

    • ONE_FIFTH

      public static final Fraction ONE_FIFTH
      Fraction representation of 1/5.

    • TWO_FIFTHS

      public static final Fraction TWO_FIFTHS
      Fraction representation of 2/5.

    • THREE_FIFTHS

      public static final Fraction THREE_FIFTHS
      Fraction representation of 3/5.

    • FOUR_FIFTHS

      public static final Fraction FOUR_FIFTHS
      Fraction representation of 4/5.

  • Method Details

    • of

      public static Fraction of(int numerator, int denominator)
      Parameters:
      numerator -
      denominator -
      Returns:
      See Also:

    • of

      public static Fraction of(int numerator, int denominator, boolean reduce)

      Creates a Fraction instance with the 2 parts of a fraction Y/Z.

      Any negative signs are resolved to be on the numerator.

      Parameters:
      numerator - the numerator, for example the three in 'three sevenths'
      denominator - the denominator, for example the seven in 'three sevenths'
      reduce - if it's true, reduce Fraction instance with the 2 parts of a fraction Y/Z. For example, if the input parameters represent 2/4, then the created fraction will be 1/2.
      Returns:
      a new fraction instance
      Throws:
      ArithmeticException - if the denominator is zero or the denominator is negative and the numerator is Integer#MIN_VALUE

    • of

      public static Fraction of(int whole, int numerator, int denominator)
      Parameters:
      whole -
      numerator -
      denominator -
      Returns:

    • of

      public static Fraction of(int whole, int numerator, int denominator, boolean reduce)

      Creates a Fraction instance with the 3 parts of a fraction X Y/Z.

      The negative sign must be passed in on the whole number part.

      Parameters:
      whole - the whole number, for example the one in 'one and three sevenths'
      numerator - the numerator, for example the three in 'one and three sevenths'
      denominator - the denominator, for example the seven in 'one and three sevenths'
      reduce -
      Returns:
      a new fraction instance
      Throws:
      ArithmeticException - if the resulting numerator exceeds Integer.MAX_VALUE

    • of

      public static Fraction of(double value)

      Creates a Fraction instance from a double value.

      This method uses the continued fraction algorithm, computing a maximum of 25 convergents and bounding the denominator by 10,000.

      Parameters:
      value - the double value to convert
      Returns:
      a new fraction instance that is close to the value
      Throws:
      ArithmeticException - if the the algorithm does not converge

    • of

      public static Fraction of(String str)

      Creates a Fraction from a String.

      The formats accepted are:

      1. double String containing a dot
      2. 'X Y/Z'
      3. 'Y/Z'
      4. 'X' (a simple whole number)

      and a .

      Parameters:
      str - the string to parse, must not be null
      Returns:
      Throws:
      IllegalArgumentException - if the string is null
      NumberFormatException - if the number format is invalid

    • getNumerator

      @Deprecated public int getNumerator()
      Deprecated.
      replaced by numerator

      Gets the numerator part of the fraction.

      This method may return a value greater than the denominator, an improper fraction, such as the seven in 7/4.

      Returns:

    • numerator

      public int numerator()

    • getDenominator

      @Deprecated public int getDenominator()
      Deprecated.
      replaced by denominator

      Gets the denominator part of the fraction.

      Returns:

    • denominator

      public int denominator()

    • getProperNumerator

      @Deprecated public int getProperNumerator()
      Deprecated.
      replaced by properNumerator

      Gets the proper numerator, always positive.

      An improper fraction 7/4 can be resolved into a proper one, 1 3/4. This method returns the 3 from the proper fraction.

      If the fraction is negative such as -7/4, it can be resolved into -1 3/4, so this method returns the positive proper numerator, 3.

      Returns:

    • properNumerator

      public int properNumerator()

    • getProperWhole

      @Deprecated public int getProperWhole()
      Deprecated.
      replaced by properWhole

      Gets the proper whole part of the fraction.

      An improper fraction 7/4 can be resolved into a proper one, 1 3/4. This method returns the 1 from the proper fraction.

      If the fraction is negative such as -7/4, it can be resolved into -1 3/4, so this method returns the positive whole part -1.

      Returns:

    • properWhole

      public int properWhole()

    • intValue

      public int intValue()

      Gets the fraction as an int. This returns the whole number part of the fraction.

      Specified by:
      intValue in class Number
      Returns:

    • longValue

      public long longValue()

      Gets the fraction as a long. This returns the whole number part of the fraction.

      Specified by:
      longValue in class Number
      Returns:

    • floatValue

      public float floatValue()

      Gets the fraction as a float. This calculates the fraction as the numerator divided by denominator.

      Specified by:
      floatValue in class Number
      Returns:

    • doubleValue

      public double doubleValue()

      Gets the fraction as a double. This calculates the fraction as the numerator divided by denominator.

      Specified by:
      doubleValue in class Number
      Returns:

    • reduce

      public Fraction reduce()

      Reduce the fraction to the smallest values for the numerator and denominator, returning the result.

      For example, if this fraction represents 2/4, then the result will be 1/2.

      Returns:
      a new reduced fraction instance, or this if no simplification possible

    • invert

      public Fraction invert()

      Gets a fraction that is the inverse (1/fraction) of this one.

      The returned fraction is not reduced.

      Returns:
      a new fraction instance with the numerator and denominator inverted.
      Throws:
      ArithmeticException - if the fraction represents zero.

    • negate

      public Fraction negate()

      Gets a fraction that is the negative (-fraction) of this one.

      The returned fraction is not reduced.

      Returns:
      a new fraction instance with the opposite signed numerator

    • abs

      public Fraction abs()

      Gets a fraction that is the positive equivalent of this one.

      More precisely: (fraction >= 0 ? this : -fraction)

      The returned fraction is not reduced.

      Returns:
      this if it is positive, or a new positive fraction instance with the opposite signed numerator

    • pow

      public Fraction pow(int power)

      Gets a fraction that is raised to the passed in power.

      The returned fraction is in reduced form.

      Parameters:
      power - the power to raise the fraction to
      Returns:
      this if the power is one, ONE if the power is zero (even if the fraction equals ZERO) or a new fraction instance raised to the appropriate power
      Throws:
      ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

    • 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.

      Parameters:
      fraction - the fraction to add, must not be null
      Returns:
      a Fraction instance with the resulting values
      Throws:
      IllegalArgumentException - if the fraction is null
      ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

    • subtract

      public Fraction subtract(Fraction fraction)

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

      Parameters:
      fraction - the fraction to subtract, must not be null
      Returns:
      a Fraction instance with the resulting values
      Throws:
      IllegalArgumentException - if the fraction is null
      ArithmeticException - if the resulting numerator or denominator cannot be represented in an int.

    • multipliedBy

      public Fraction multipliedBy(Fraction fraction)

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

      Parameters:
      fraction - the fraction to multiply by, must not be null
      Returns:
      a Fraction instance with the resulting values
      Throws:
      IllegalArgumentException - if the fraction is null
      ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

    • dividedBy

      public Fraction dividedBy(Fraction fraction)

      Divide the value of this fraction by another.

      Parameters:
      fraction - the fraction to divide by, must not be null
      Returns:
      a Fraction instance with the resulting values
      Throws:
      IllegalArgumentException - if the fraction is null
      ArithmeticException - if the resulting numerator or denominator exceeds Integer.MAX_VALUE

    • compareTo

      public int compareTo(Fraction other)

      Compares this object to another based on size.

      Note: this class has a natural ordering that is inconsistent with equals, because, for example, equals treats 1/2 and 2/4 as different, whereas compareTo treats them as equal.

      Specified by:
      compareTo in interface Comparable<Fraction>
      Parameters:
      other - the object to compare to
      Returns:
      -1 if this is less, 0 if equal, +1 if greater
      Throws:
      ClassCastException - if the object is not a Fraction
      NullPointerException - if the object is null

    • toProperString

      public String toProperString()

      Gets the fraction as a proper String in the format X Y/Z.

      The format used in 'wholeNumber numerator/denominator'. If the whole number is zero it will be omitted. If the numerator is zero, only the whole number is returned.

      Returns:
      a String form of the fraction

    • equals

      public boolean equals(Object obj)

      Compares this fraction to another object to test if they are equal.

      .

      To be equal, both values must be equal. Thus 2/4 is not equal to 1/2.

      Overrides:
      equals in class Object
      Parameters:
      obj - the reference object with which to compare
      Returns:
      true if this object is equal

    • hashCode

      public int hashCode()

      Gets a hashCode for the fraction.

      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this object

    • toString

      public String toString()

      Gets the fraction as a String.

      The format used is 'numerator/denominator' always.

      Overrides:
      toString in class Object
      Returns:
      a String form of the fraction