calculateMinorTickMarks implementation for logarithmic axis

LogarithmicAxis.java

/**
* {@inheritDoc}
*/
@Override
protected List<Number> calculateMinorTickMarks() {
	Number[] range = getRange();
	List<Number> minorTickMarksPositions = new ArrayList<Number>();
	if (range != null) {

		Number upperBound = range[1];
		double logUpperBound = Math.log10(upperBound.doubleValue());
		int minorTickMarkCount = getMinorTickCount();

		for (double i = 0; i <= logUpperBound; i += 1) {
			for (double j = 0; j <= 9; j += (1. / minorTickMarkCount)) {
				double value = j * Math.pow(10, i);
				minorTickMarksPositions.add(value);
			}
		}
	}
	return minorTickMarksPositions;
}