Question

You need to complete the methods getSmallerValue, getLargerValue, compareTo, and equals.

Code:

public class Domino implements Comparable<Domino> {

/**

* The smallest possible value for a side of a domino.

*/

public static final int MIN_VALUE = 0;

/**

* The largest possible value for a side of a domino.

*/

public static final int MAX_VALUE = 6;

/**

* The two values on the domino.

*/

private int val1;

private int val2;

public Domino() {

this(0, 0);

}

public Domino(int value1, int value2) {

if (!isValueOK(value1) || !isValueOK(value2)) {

throw new IllegalArgumentException();

}

this.val1 = value1;

this.val2 = value2;

}

public Domino(Domino other) {

this(other.val1, other.val2);

}

private static boolean isValueOK(int value) {

return value >= MIN_VALUE && value <= MAX_VALUE;

}

@Override

public int hashCode() {

return this.getSmallerValue() + 11 * this.getLargerValue();

}

@Override

public String toString() {

return "[" + this.getSmallerValue() + " : " + this.getLargerValue() + "]";

}

/*

* You need to implement the four methods below. Both compareTo and equals

* should make use of getSmallerValue and getLargerValue.

*/

public int getSmallerValue() {

}

public int getLargerValue() {

}

@Override

public int compareTo(Domino other) {

}

@Override

public boolean equals(Object obj) {

}

}

Answer 1

public class Domino implements Comparable<Domino> {
    /**
     * The smallest possible value for a side of a domino.
     */
    public static final int MIN_VALUE = 0;
    /**
     * The largest possible value for a side of a domino.
     */
    public static final int MAX_VALUE = 6;
    /**
     * The two values on the domino.
     */
    private int val1;
    private int val2;

    public Domino() {
        this(0, 0);
    }

    public Domino(int value1, int value2) {
        if (!isValueOK(value1) || !isValueOK(value2)) {
            throw new IllegalArgumentException();
        }
        this.val1 = value1;
        this.val2 = value2;
    }

    public Domino(Domino other) {
        this(other.val1, other.val2);
    }

    private static boolean isValueOK(int value) {
        return value >= MIN_VALUE && value <= MAX_VALUE;
    }

    @Override
    public int hashCode() {
        return this.getSmallerValue() + 11 * this.getLargerValue();
    }

    @Override
    public String toString() {
        return "[" + this.getSmallerValue() + " : " + this.getLargerValue() + "]";
    }

    /*
     * You need to implement the four methods below. Both compareTo and equals
     * should make use of getSmallerValue and getLargerValue.
     */
    public int getSmallerValue() {
        if (val1 < val2) {
            return val1;
        } else {
            return val2;
        }
    }

    public int getLargerValue() {
        if (val1 > val2) {
            return val1;
        } else {
            return val2;
        }
    }

    @Override
    public int compareTo(Domino other) {
        if (val1 == other.val1) {
            return val2 - other.val2;
        }
        return val1 - other.val1;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        Domino domino = (Domino) obj;
        return val1 == domino.val1 && val2 == domino.val2;
    }
}