calculateTickValues implementation for logarithmic axis

LogarithmicAxis.java

/**
 * {@inheritDoc}
 */
@Override
protected List<Number> calculateTickValues(double length, Object range) {
	List<Number> tickPositions = new ArrayList<Number>();
	if (range != null) {
		Number lowerBound = ((Number[]) range)[0];
		Number upperBound = ((Number[]) range)[1];
		double logLowerBound = Math.log10(lowerBound.doubleValue());
		double logUpperBound = Math.log10(upperBound.doubleValue());
		for (double i = 0; i <= logUpperBound; i += 1) {
			for (double j = 1; j <= 9; j++) {
				double value = j * Math.pow(10, i);
				tickPositions.add(value);
			}
		}
	}
	return tickPositions;
}