Android Open Source - AstroPhysCalc Fraction

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Back to project page AstroPhysCalc.

License

The source code is released under:

Apache License

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Java Source Code

package org.astrophyscalc;
//from w w w .  j a  v a 2s .c o m
public class Fraction {

  private final int numerator;
  private final int denominator;

  public static Fraction ONE = new Fraction(1, 1);
  public static Fraction ZERO = new Fraction(0, 1);

  static final String DENOMINATOR_ZERO = "Denominator cannot be zero";

  public static Fraction create(final int numerator, final int denominator) {
    int newNumerator = numerator;
    int newDenominator = denominator;
    if (denominator == 0) {
      throw new IllegalArgumentException(DENOMINATOR_ZERO);
    }

    // Force denominator to always be positive
    if (denominator < 0) {
      newDenominator *= -1;
      newNumerator *= -1;
    }

    if (newNumerator == newDenominator) {
      return ONE;
    }
    if (newNumerator == -newDenominator) {
      return new Fraction(-1, 1);
    }
    if (newNumerator == 0) {
      return ZERO;
    }

    return new Fraction(newNumerator, newDenominator);
  }

  private Fraction(final int numerator, final int denominator) {
    this.numerator = numerator;
    this.denominator = denominator;
  }

  public int getNumerator() {
    return numerator;
  }

  public int getDenominator() {
    return denominator;
  }

  public boolean isOne() {
    return this == ONE;
  }

  public boolean isZero() {
    return this == ZERO;
  }

  public double toDouble() {
    return (double) numerator / (double) denominator;
  }

  public Fraction add(final Fraction fraction2) {
    // TODO: factor out common factors
    final int newDenominator = getDenominator() * fraction2.getDenominator();

    final int newNumerator1 = getNumerator() * fraction2.getDenominator();
    final int newNumerator2 = fraction2.getNumerator() * getDenominator();

    final Fraction newFraction = Fraction.create(newNumerator1 + newNumerator2, newDenominator);
    return newFraction;
  }

  public Fraction subtract(final Fraction fraction2) {
    return add(fraction2.negative());
  }

  public Fraction pow(final Fraction exponent) {
    final int newNumerator = getNumerator() * exponent.getNumerator();
    final int newDenominator = getDenominator() * exponent.getDenominator();

    return Fraction.create(newNumerator, newDenominator);
  }

  public Fraction negative() {
    return Fraction.create(-getNumerator(), getDenominator());
  }

  @Override
  public boolean equals(final Object object) {
    if (!(object instanceof Fraction)) {
      return false;
    }

    Fraction fraction = (Fraction) object;

    return numerator == fraction.getNumerator() && denominator == fraction.getDenominator();
  }

  @Override
  public String toString() {
    return Fraction.class.getSimpleName() + ": " + numerator + ", " + denominator;
  }

}

Java Source Code List