Method getBaseUnit

base/src/main/java/net/time4j/engine/TimeAxis.java:355–378

(ChronoElement<?> element)

     * @see     BasicElement#getParent()
     */
    public U getBaseUnit(ChronoElement<?> element) {

        if (element == null) {
            throw new NullPointerException("Missing element.");
        }

        U baseUnit = this.baseUnits.get(element);

        if (
            (baseUnit == null)
            && (element instanceof BasicElement)
        ) {
            ChronoElement<?> parent = ((BasicElement) element).getParent();
            baseUnit = this.baseUnits.get(parent);
        }

        if (baseUnit == null) {
            throw new ChronoException(
                "Base unit not found for: " + element.name());
        }

        return baseUnit;

    }

    /**
     * <p>Compares time units by ascending precision (that is descending length). </p>