package matrix;

import java.util.List;

public class PaginationHelper {

public static void main(String[] args) {

}

class PaginationHelper1<I> {

private final List<I> collection;

private final int itemsPerPage;

public PaginationHelper1(List<I> collection, int itemsPerPage) {

this.collection = collection;

this.itemsPerPage = itemsPerPage;

}

public int itemCount() {

return collection.size();

}

public int pageCount() {

double result = (double) collection.size() / itemsPerPage;

return (int) Math.ceil(result);

}

public int pageItemCount(int pageIndex) {

if (pageIndex < 0 || pageIndex >= pageCount()) return -1;

if (pageIndex == pageCount() - 1) return collection.size() % itemsPerPage;

return itemsPerPage;

}

public int pageIndex(int itemIndex) {

if (itemIndex < 0 || itemIndex >= collection.size()) return -1;

return itemIndex / itemsPerPage;

}

}

}