Contents

./Chicken.java

/**
 * A simple Java class that models a Chicken. The state of the chicken is its
 * name, height, weight, and gender.
 * 
 * @author Sara Sprenkle
 */
public class Chicken {

    // ------------ INSTANCE VARIABLES -------------------

    /** the chicken's name */
	private String name;
	
    /** the height of the chicken in centimeters */
	private int height;
    
    /** the weight of the chicken in pounds */
	private double weight;
    
    /** true iff the chicken is a female */
    private boolean isFemale;
    
    public static String DEFAULT_NAME = "BUBBA";

    /**
     * @param name the name of the chicken
     * @param height the height of the chicken in centimeters
     * @param weight the weight of the chicken in pounds
     * @param isFemale whether the chicken is female
     */
    public Chicken(String name, int height, double weight, boolean isFemale ) {
        this.name = name;
        this.height = height;
        this.weight = weight;
        this.isFemale = isFemale;
    }
    
   /**
    * Assumes Chickens are females
    * @param name the name of the chicken
    * @param height the height of the chicken in centimeters
    * @param weight the weight of the chicken in pounds
    */
    public Chicken(String name, int height, double weight) {
        this( name, height, weight, true );
    }
    
    /**
     * Default name is Bubba (defined by DEFAULT_NAME)
     * Assumes Chickens are female
     * @param height the height of the chicken in centimeters
     * @param weight the weight of the chicken in pounds
     */
    public Chicken( int height, double weight ) {
        this( DEFAULT_NAME, height, weight, true);
    }
    
    /**
     * Returns a string representation of the chicken.
     * Format:
     * Chicken name: <name>
     * <br/>weight: &lt;weight&gt;
     * <br/>height: &lt;height&gt;
     * <br/>female/male
     */
    @Override
    public String toString() {
        StringBuilder rep = new StringBuilder("Chicken name: ");
        rep.append(name);
        rep.append("\nweight: ");
        rep.append(weight);
        rep.append("\nheight: ");
        rep.append(height);
        rep.append("\n");
        rep.append( isFemale? "female" : "male"); // Java ternary operator; also available in C
        return rep.toString();
    } 
    

    /**
     * Determines if two Chickens are equivalent, based on their
     * name, height, weight, and gender.
     */
     @Override
    public boolean equals(Object o) {
        
        if( o == this ) {
            return true;   
        }
        
        if ( ! (o instanceof Chicken ) ) {
            return false;   
        }
        
        Chicken other = (Chicken) o;
        
        if( ! other.getName().equals(this.getName() ) ) {
            return false;
        }
        
        if( other.getHeight() != this.getHeight() ) {
            return false;   
        }
        
        // From Effective Java,
        
        // "The special treatment of float and double fields is made necessary
        // by the existence of Float.NaN, -0.0f and the analogous double
        // constants"
        if( Double.compare( other.getWeight(), this.getWeight() ) != 0 ) {
            return false;   
        }
        
        if( this.isFemale() ) {
            return other.isFemale();
        } else {
            return ! other.isFemale();
        }
        
    }
    
	//
	// ----------- GETTER METHODS ------------
	// (also Accessor methods)

    /**
     * @return the height of the chicken, in centimeters
     */
    public int getHeight() {
        return height;
    }
    
    /**
     * @return the weight of the chicken, in pounds
     */
    public double getWeight() {
        return weight;
    }
    
    /**
     * @return the name of the chicken
     */
    public String getName() {
        return name;
    }
    
    public boolean isFemale() {
        return isFemale;   
    }
    

    //
    // ------------- MUTATORS -----------
    //
    
    /**
     * Feeds the chicken--making the chicken grow
     */
    public void feed() {
        // Better: create constants for these values
        weight += .2;
        height += 1;
    }
	
    //
    // ------------- SETTERS ----------
    //
    
    /**
     * @param n
     *            the name of the chicken
     */
    public void setName(String n) {
        name = n;
    }
    
    /**
     * @param h
     *            the height of the chicken, in cm
     */
    public void setHeight(int h) {
        height = h;
    }
    
    /**
     * @param w
     *            the weight of the chicken, in pounds
     */
    public void setWeight(double w) {
        weight = w;
    }

    /**
     * @param args
     *            the command-line arguments
     */
    public static void main(String args[]) {
        Chicken one = new Chicken("Fred", 38, 2.0, false);
        Chicken two = new Chicken("Sallie Mae", 45, 3.0);
        Chicken closeToTwo = new Chicken("Sallie Mae", 45, 3.0000000001);
        Chicken oneFemale = new Chicken("Fred", 38, 2.0, true);
        
        System.out.println("one chicken: " + one);
        System.out.println(one.getName() + " weighs " + one.getWeight() );
        one.feed();
        System.out.println(one.getName() + " ate, so he now weighs " + one.getWeight() );
        System.out.println();
        
        System.out.println(one);
        System.out.println(two);
        
        System.out.println( one + " equal to " + two + "? " + one.equals(two) );
        System.out.println();
    
        System.out.println( one + " equal to " + oneFemale + "? " + one.equals(oneFemale) );
        System.out.println();
    
        System.out.println( two + " equal to " + two + "? " + two.equals(two) );
        System.out.println();
    
        System.out.println( two + " equal to " + closeToTwo + "? " + two.equals(closeToTwo) );
    }

}