import java.util.*;
import java.io.*;

public class CompareTest {
    public static void main(String[] args) throws IOException {
        List<Integer> ints = new ArrayList<Integer>();
        List<File> files = new ArrayList<File>();
        for (int i = 0; i < 245; ++i) {
            ints.add(i);
        }
        Collections.shuffle(ints);

        for (Integer i : ints) {
            File file = new File("file-" + i);
            file.createNewFile();
            files.add(file);
        }

        compare(ints, new IntsComparator());
        compare(files, new FilesComparator());
    }

    private static <T> void compare(List<T> list, CountingComparator<T> comparator) {
        int startCount = comparator.getCount();
        long start = System.nanoTime();
        Collections.sort(list, comparator);
        long end = System.nanoTime();
        long nanos = end - start;
        double seconds = nanos / 1000000000.0D;
        int endCount = comparator.getCount();
        System.out.printf("%s took %f seconds with %d comparisons%n", comparator.getClass().getSimpleName(), seconds, endCount - startCount);
    }

    private interface CountingComparator<T> extends Comparator<T> {
        int getCount();
    }

    private static class IntsComparator implements CountingComparator<Integer>
    {
        @Override
        public int compare(Integer o1, Integer o2) {
            ++count;
            return o1 - o2;
        }

        @Override
        public int getCount() {
            return count;
        }

        int count = 0;
    }

    private static class FilesComparator implements CountingComparator<File>
    {
        @Override
        public int compare(File o1, File o2) {
            ++count;
            return (int)(o1.lastModified() - o2.lastModified());
        }

        @Override
        public int getCount() {
            return count;
        }

        int count = 0;
    };
}