Fraction

java.lang.Object
- ca.roumani.i2c.Fraction

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Fraction>

Direct Known Subclasses:

MixedNumber
```
public class Fraction
extends java.lang.Object
implements java.io.Serializable, java.lang.Comparable<Fraction>
```
This class encapsulates a fraction. It maintains the fraction's state (numerator and denominator) and provides functionality for manipulating fractions. The class ensures that the denominators of all its instances are non-negative at all times by transferring any negative denominator sign to the numerator. Furthermore, the fraction is kept in reduced form at all times, i.e. with no common divisor greater than 1. Note that the numerator and denominator are of the int type, and hence, they maintain closure by wrapping the int range. Note also that a Fraction instance can have a zero denominator either upon creation or after an operation. Such an instance is treated like any other (it can, for example, participate in the operations supported by the class without leading to exceptions) except for two differences:
1. When invoked on such an instance, the toString method returns the literal NaF, which stands for "Not a Fraction".
2. All such instances are considered equal (regardless of their numerator values) and greater than any non-zero denominator fraction. This affects the contracts of compareTo and equals.
Version:

0.1

Author:

H. Roumani, prof@roumani.ca

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static boolean`	`isQuoted` A flag that determines if the return of the `toProperString()` method is surrounded by quotes or not.
`char`	`separator` A character that separates the numerator denominator pair in the return of the `toString()` method.

Constructor Summary

Constructors
Constructor and Description
`Fraction()` Construct a default fraction with numerator equal to 0, denominator equal to 1, and separator equal to '/'.
`Fraction(Fraction fraction)` Construct a copy of the passed Fraction.
`Fraction(int numerator, int denominator)` Construct a fraction with the passed numerator and denominator and a '/' separator.
`Fraction(int numerator, int denominator, char separator)` Construct a fraction with the passed numerator, denominator, and separator.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`add(Fraction other)` Add the passed fraction to the fraction on which it was called.
`Fraction`	`cloneMe()` Copy the state of `this` object.
`int`	`compareTo(Fraction other)` Compare this object with the specified object for order.
`void`	`divide(Fraction other)` Divide the fraction on which the method was called by the passed fraction.
`boolean`	`equals(java.lang.Object other)` Determine if `this` fraction is the same as the passed one.
`int`	`getDenominator()` An accessor to the denominator of `this` fraction.
`int`	`getNumerator()` An accessor to the numerator of `this` fraction.
`static Fraction`	`getRandom()` Create a random fraction.
`char`	`getSeparator()` An accessor to the separator of `this` fraction.
`int`	`hashCode()` Compute a hash code for `this` Fraction.
`void`	`multiply(Fraction other)` Multiply the fraction on which the method was called by the passed fraction.
`void`	`pow(int exponent)` Raise the fraction on which the method was called to the passed exponent.
`boolean`	`resembles(Fraction other)` Determine if `this` fraction resembles the passed one.
`void`	`setDenominator(int denominator)` A mutator for the denominator of `this` fraction.
`void`	`setFraction(Fraction other)` A mutator for `this` fraction.
`void`	`setFraction(int numerator, int denominator)` A mutator for `this` fraction.
`void`	`setNumerator(int numerator)` A mutator of the numerator of `this` fraction.
`static void`	`setSeed(int seed)` Change the seed of the random sequence returned by `getRandom()`.
`boolean`	`setSeparator(char newSeparator)` A mutator of the separator of `this` fraction.
`void`	`subtract(Fraction other)` Subtract the passed fraction from the fraction on which it was called.
`java.lang.String`	`toProperString()` Return `this` fraction as a proper fraction.
`java.lang.String`	`toString()` Return a string representation of `this` fraction.

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - separator
```
public char separator
```
    A character that separates the numerator denominator pair in the return of the toString() method. The default value is '/'.
    (Bad design--should have been kept private. Access would have still been possible via the existing public accessor and mutator.)
  - isQuoted
```
public static boolean isQuoted
```
    A flag that determines if the return of the toProperString() method is surrounded by quotes or not. The default value is true.
    (Bad design--should have been kept private. Access would have still been possible via a public static accessor, e.g. isQuoted() and a public static mutator, e.g. setIsQuoted(boolean).)
- Constructor Detail
  - Fraction
```
public Fraction()
```
    Construct a default fraction with numerator equal to 0, denominator equal to 1, and separator equal to '/'. The rational value of the constructed fraction is, thus, zero.
  - Fraction
```
public Fraction(int numerator,
                int denominator)
```
    Construct a fraction with the passed numerator and denominator and a '/' separator. If the passed denominator is negative, the sign of the numerator is reversed in order to keep the denominator positive.
    
    Parameters:
    
    numerator - the numerator of the fraction to construct.
    
    denominator - the denominator of the fraction to construct.
  - Fraction
```
public Fraction(Fraction fraction)
```
    Construct a copy of the passed Fraction.
    
    Parameters:
    
    fraction - the Fraction to copy.
    
    Throws:
    
    java.lang.RuntimeException - if fraction = null
  - Fraction
```
public Fraction(int numerator,
                int denominator,
                char separator)
```
    Construct a fraction with the passed numerator, denominator, and separator. If the passed denominator is negative, the sign of the numerator is reversed in order to keep the denominator positive, and if the passed separator is a letter or a digit, it is replaced with '/'.
    
    Parameters:
    
    numerator - the numerator of the fraction to construct.
    
    denominator - the denominator of the fraction to construct.
    
    separator - the separator of the fraction to construct.
- Method Detail
  - add
```
public void add(Fraction other)
```
    Add the passed fraction to the fraction on which it was called. This method is, in effect, a mutator because it changes the state of the encapsulated object.
    
    Parameters:
    
    other - the fraction to add to this fraction.
  - subtract
```
public void subtract(Fraction other)
```
    Subtract the passed fraction from the fraction on which it was called. This method is, in effect, a mutator because it changes the state of the encapsulated object.
    
    Parameters:
    
    other - the fraction to subtract from thisfraction.
  - multiply
```
public void multiply(Fraction other)
```
    Multiply the fraction on which the method was called by the passed fraction. This method is, in effect, a mutator because it changes the state of the encapsulated object.
    
    Parameters:
    
    other - the fraction to multiply this fraction by
  - divide
```
public void divide(Fraction other)
```
    Divide the fraction on which the method was called by the passed fraction. This method is, in effect, a mutator because it changes the state of the encapsulated object.
    
    Parameters:
    
    other - the fraction to divide this fraction by
  - pow
```
public void pow(int exponent)
```
    Raise the fraction on which the method was called to the passed exponent. This method is, in effect, a mutator because it changes the state of the encapsulated object.
    
    Parameters:
    
    exponent - the exponent to raise this fraction to (must be non-negative).
    
    Throws:
    
    java.lang.RuntimeException - if the exponent is negative.
  - setNumerator
```
public void setNumerator(int numerator)
```
    A mutator of the numerator of this fraction.
    
    Parameters:
    
    numerator - the new numerator.
  - getNumerator
```
public int getNumerator()
```
    An accessor to the numerator of this fraction.
    
    Returns:
    
    the numerator of this fraction.
  - setDenominator
```
public void setDenominator(int denominator)
```
    A mutator for the denominator of this fraction.
    
    Parameters:
    
    denominator - the new denominator.
  - getDenominator
```
public int getDenominator()
```
    An accessor to the denominator of this fraction.
    
    Returns:
    
    the denominator of this fraction.
  - setFraction
```
public void setFraction(int numerator,
                        int denominator)
```
    A mutator for this fraction.
    
    Parameters:
    
    numerator - the new numerator of the fraction.
    
    denominator - the new denominator of the fraction.
  - setFraction
```
public void setFraction(Fraction other)
```
    A mutator for this fraction.
    
    Parameters:
    
    other - the fraction whose numerator and denominator will become those of this fraction.
  - setSeparator
```
public boolean setSeparator(char newSeparator)
```
    A mutator of the separator of this fraction. The separator must not be a letter or a digit.
    
    Parameters:
    
    newSeparator - the new separator.
    
    Returns:
    
    true if the change was made (i.e. if the passed parameter is neither a letter nor a digit), and return false otherwise.
  - getSeparator
```
public char getSeparator()
```
    An accessor to the separator of this fraction.
    
    Returns:
    
    the separator of this fraction.
  - toString
```
public java.lang.String toString()
```
    Return a string representation of this fraction. Note that the literal "NaF" (Not A Fraction) is returned if the denominator is zero to indicate that this is not a valid fraction.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the numerator and denominator of this fraction separated by separator.
  - toProperString
```
public java.lang.String toProperString()
```
    Return this fraction as a proper fraction. Note that the literal "NaF" (Not A Fraction) is returned if the denominator is zero to indicate that this is not a valid fraction.
    
    Returns:
    
    a string representation of of this fraction in the form:
    w n/d
    where w is a whole number and n < d. The n/d part and the space that precedes it are not present if the numerator of this fraction is divisible by its denominator. The return is surrounded by double quotes if isQuoted is true.
  - equals
```
public boolean equals(java.lang.Object other)
```
    Determine if this fraction is the same as the passed one. Two fractions are considered equal if they have the same numerator and denominator (in reduced form).
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    other - a reference to the object to test equality with.
    
    Returns:
    
    true if other is not null and points to a fraction that is equal to this one. The return is false otherwise. Note that all zero-denominator fractions are considered equal.
  - hashCode
```
public int hashCode()
```
    Compute a hash code for this Fraction.
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    a hash code value for this object.
  - resembles
```
public boolean resembles(Fraction other)
```
    Determine if this fraction resembles the passed one. Two fractions are said to resemble each other if they have a common denominator.
    
    Parameters:
    
    other - a reference to the object to test resemblance with.
    
    Returns:
    
    true if other is not null and does resemble this object. The return is false otherwise.
  - getRandom
```
public static Fraction getRandom()
```
    Create a random fraction. The numerators and denominators of the created fractions are uniformly distributed in [0,1000) but no zero-denominator fraction is generated.
    This method was added for pedagogical reasons.
    
    Returns:
    
    a randomly chosen fraction.
  - setSeed
```
public static void setSeed(int seed)
```
    Change the seed of the random sequence returned by getRandom(). This method is meant to be used by a test harness so that the same sequence can be generated for the app being tested and its oracle.
    
    Parameters:
    
    seed - the initial seed for random number generator.
  - cloneMe
```
public Fraction cloneMe()
```
    Copy the state of this object.
    
    Returns:
    
    a reference to a new Fraction object having exactly the same state as this one.
  - compareTo
```
public int compareTo(Fraction other)
```
    Compare this object with the specified object for order. Return a negative integer, zero, or a positive integer if this object is less than, equal to, or greater than the specified object.
    
    Specified by:
    
    compareTo in interface java.lang.Comparable<Fraction>
    
    Parameters:
    
    other - the Object to compare to.
    
    Returns:
    
    -1 if this fraction is less than the passed one, +1 if it is greater, and 0 if they are equal. Note that all zero-denominator fractions are considered equal and greater than any other fraction.

Class Fraction

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

separator

isQuoted

Constructor Detail

Fraction

Fraction

Fraction

Fraction

Method Detail

add

subtract

multiply

divide

pow

setNumerator

getNumerator

setDenominator

getDenominator

setFraction

setFraction

setSeparator

getSeparator

toString

toProperString

equals

hashCode

resembles

getRandom

setSeed

cloneMe

compareTo