ListUtils.java

public class ListUtils {


    /**
     * Partitions lists into batches of minimum and maximum size.
     * examples when min=2, max=4:
     * [1, 2, 3, 4 ,5] -> [[1, 2, 3], [4, 5]]
     * [1, 2, 3, 4] -> [[1, 2, 3, 4]]
     * [1, 2, 3, 4, 5 ,6] -> [[1, 2, 3, 4] [5, 6]]
     * @param originalList - list to parition
     * @param max - maximum size of sublist
     * @param min - minimum size of sublist
     * @return
     */
    public static <T> List<List<T>> partition(List<T> originalList, int max, int min) {
        if (originalList.size() <  min) {
            throw new IllegalArgumentException("list size is smaller than the minimum");
        }

        List<List<T>> partitioned = new ArrayList<>(Lists.partition(originalList, max));

        if (partitioned.size() >= 2) {
            int lastIndex = partitioned.size() - 1;
            int beforeLastIndex = partitioned.size() - 2;
            LinkedList<T> lastList = new LinkedList<>(partitioned.get(lastIndex));
            LinkedList<T> beforeLastList = new LinkedList<>(partitioned.get(beforeLastIndex));
            while (lastList.size() < min) {
                lastList.addFirst(beforeLastList.removeLast());
            }
            partitioned.set(lastIndex, lastList);
            partitioned.set(beforeLastIndex, beforeLastList);
        }

        return partitioned;
    }

}