Ordering a list by an attribute of the elements

Question

I have a java arraylist:

List<Log> logs = new ArrayList<Log>();

Log class has the following attributes:

String type;
int num;
Date date;

What would be a good way to order the logs list by date?

I refer you to this: [http://stackoverflow.com/questions/4066538/sort-an-arraylist-based-on-an-object-field](http://stackoverflow.com/questions/4066538/sort-an-arraylist-based-on-an-object-field) — Justice, Oct 27 '15 at 02:32
those answers are too old. there are better solutions in java8. — ZhongYu, Oct 27 '15 at 02:34

score 0 · Answer 1 · answered Oct 27 '15 at 02:33

You can implements a Comparator interface as the followings:

import java.util.ArrayList;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
public class Main {
    public static void main(String arg[]) {
        List<Log> logs = new ArrayList<Log>();
        logs.sort(new CustomComparator());
    }
}

class CustomComparator implements Comparator<Log> {
    @Override
    public int compare(Log o1, Log o2) {
        return o1.date.compareTo(o2.date);
    }
}

class Log {
    String type;
    int num;
    Date date;
}

please notice using the sort function

Ordering a list by an attribute of the elements

1 Answers1