Iterator [Java] class DaysOfTheWeek implements Iterable - class DaysIterator implements Iterator

Series

Iterator [Java] class DaysOfTheWeek implements Iterable - class DaysIterator implements Iterator

More Code 2018. 6. 16. 04:43

// Java : Iterator

package iteration;

import java.util.Iterator;

public class Program {

    public static void main(String[] args) {
        DaysOfTheWeek weekDays = new DaysOfTheWeek();

        for (Object day : weekDays) {
            System.out.println(day);
        }

        System.out.println("---- End of 1st iteration ----");

        Iterator it = weekDays.iterator();
        while (it.hasNext()) {
            Object day = it.next();
            System.out.println(day);
        }

        System.out.println("---- End of 2nd iteration ----");

        it = weekDays.iterator();
        while (it.hasNext()) {
            Object day = it.next();
            System.out.println(day);
        }

        System.out.println("---- End of 3rd iteration ----");
    }
}

class DaysOfTheWeek implements Iterable {

    public Iterator iterator() {
        return new DaysIterator();
    }
}

class DaysIterator implements Iterator {

    private String[] days = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
    int index;

    public DaysIterator() {
        index = -1;
    }

    public boolean hasNext() {
        return index + 1 < days.length;
    }

    public String next() {
        index++;
        return days[index];
    }

    public void remove() {
        throw new UnsupportedOperationException();
    }
}