Rational Value

package calculator.datatypes.rational;

import calculator.AbstractValue;
import calculator.DivisionByZeroException;
import calculator.OperationNotSupportedException;

public class RationalValue extends AbstractValue {
    private int numerator;
    private int denominator;

    public RationalValue(int numerator, int denominator) {

        this.numerator = numerator;

        if (denominator != 0) {
            this.denominator = denominator;
        }
        else {
            throw new IllegalArgumentException("Division by zero");
        }
    }

    @Override
    public AbstractValue add(AbstractValue operand) throws OperationNotSupportedException {
        int num = ((RationalValue)operand).numerator;
        int denom = ((RationalValue)operand).denominator;

        return new RationalValue( numerator*denom + num*denominator , denominator*denom );
    }

    @Override
    public AbstractValue sub(AbstractValue operand) throws OperationNotSupportedException {
        int num = ((RationalValue)operand).numerator;
        int denom = ((RationalValue)operand).denominator;

        return new RationalValue( numerator*denom - num*denominator , denominator*denom );
    }

    @Override
    public AbstractValue mul(AbstractValue operand) throws OperationNotSupportedException {
        int num = ((RationalValue)operand).numerator;
        int denom = ((RationalValue)operand).denominator;

        return new RationalValue( numerator*num, denominator*denom );
    }

    @Override
    public AbstractValue div(AbstractValue operand) throws DivisionByZeroException, OperationNotSupportedException {
        int num = ((RationalValue)operand).numerator;
        int denom = ((RationalValue)operand).denominator;

        return new RationalValue( numerator*denom, denominator*num );
    }

    @Override
    public String toString() {
        return Double.toString(numerator) + "/" + Double.toString(denominator);
    }

}