Question

Implement the Nickel class. Include Javadoc comments for the class, public fields, constructors, and methods of the class.

I have added the Javadoc comments but please feel free to format them if they are done incorrectly.

public class Nickel implements Comparable {

private int year;

/**

* The monetary value of a nickel in cents.

*/

public final int CENTS = 5;

/**

* Initializes this nickel to have the specified issue year.

*

* @param year

*

* @pre. year must be greater than or equal to 1858

*/

Nickel (int year){

}

/**

* Returns the issue year of this coin.

* @return

*/

public int issueYear() {

}

/**

* Compares this nickel to the specified object for equality. The result is true if obj

* is a nickel. The issue year is not considered when comparing two nickels for equality.

*

* @param obj

*

* @return

*/

public boolean equals​(Object obj) {

}

/**

* Returns a hash code for this nickel. Specifically, this method returns the issue year of this nickel.

*/

public int hashCode() {

}

/**

* Compares this nickel to another nickel by their issue year.

* The result is a negative integer if this nickel has an earlier issue year than

* the other nickel, a positive integer if this nickel has a later issue year than

* the the other nickel, and zero otherwise. Specifically, this method returns the

* difference of the issue year of this nickel and the issue year of the other nickel.

*

* @param other

*

* @return

*/

@Override

public int compareTo(Nickel o) {

}

}

Answer 1

public class Nickel implements Comparable<Nickel> {
    private int year;
    /**
     * The monetary value of a nickel in cents.
     */
    public final int CENTS = 5;

    /**
     * Initializes this nickel to have the specified issue year.
     *
     * @param year
     * @pre. year must be greater than or equal to 1858
     */
    Nickel(int year) {
        if (year < 1858)
            throw new IllegalArgumentException();
        this.year = year;
    }

    /**
     * Returns the issue year of this coin.
     *
     * @return
     */
    public int issueYear() {
        return year;
    }

    /**
     * Compares this nickel to the specified object for equality. The result is true if obj
     * <p>
     * is a nickel. The issue year is not considered when comparing two nickels for equality.
     *
     * @param obj
     * @return
     */
    @Override
    public boolean equals(Object obj) {
        return obj != null && getClass() == obj.getClass();
    }

    /**
     * Returns a hash code for this nickel. Specifically, this method returns the issue year of this nickel.
     */
    public int hashCode() {
        return year;
    }

    /**
     * Compares this nickel to another nickel by their issue year.
     * <p>
     * The result is a negative integer if this nickel has an earlier issue year than
     * <p>
     * the other nickel, a positive integer if this nickel has a later issue year than
     * <p>
     * the the other nickel, and zero otherwise. Specifically, this method returns the
     * <p>
     * difference of the issue year of this nickel and the issue year of the other nickel.
     *
     * @param other
     * @return
     */
    @Override
    public int compareTo(Nickel other) {
        return year - other.year;
    }
}