How to sort Objects in an arrayList using a comparable date field

Question

For example, if I have an arraylist contains one kind of Object that has a date field implement comparable interface, like a string. How can I sort this arraylist using this date field. It is a generic method, therefore I can't write my own comparator method.

@GauravaAgarwal I think I should give more details about my question. It is a generic method, therefore I can't write my own comparator method — Stewie Griffin, Jul 12 '16 at 05:55
Can you post fields inside your target class, whose object you wish to sort? — Gaurava Agarwal, Jul 12 '16 at 06:00
@GauravaAgarwal Generic Type T,that might be any object that has a unknown type comparable field R — Stewie Griffin, Jul 12 '16 at 06:10

Gaurava Agarwal · Answer 1 · 2016-07-12T06:50:00.207

Your problem is not very clear to me. But based on my understanding I have written some code. Kindly give your feedback if below solution is somewhat near to your problem.

    interface DateCompare<H extends DateCompare> extends Comparable<H> {
    public Date getDate();
  }

class ActualClass<H extends DateCompare> implements DateCompare<H> {
    Date date;
    public ActualClass() {
        date=new Date();
    }
    public int compareTo(H o) {
        return this.getDate().compareTo(o.getDate());
    }
    public Date getDate() {
        return date;
    }
}

class ActualService <T extends DateCompare<DateCompare>> {
    List<T> list = new ArrayList<T>();
}

How to sort Objects in an arrayList using a comparable date field

1 Answers1