Review

class DoubleRange {
    /**
     * <p>Tests whether the specified <code>number</code> occurs within
     * this range using <code>double</code> comparison.</p>
     * 
     * <p><code>null</code> is handled and returns <code>false</code>.</p>
     *
     * @param number  the number to test, may be <code>null</code>
     * @return <code>true</code> if the specified number occurs within this range
     */
    public boolean containsNumber(Number number) {
        if (number == null) {
            return false;
        }
        return containsDouble(number.doubleValue());
    }

}