mapっぽいの

Util.java

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

public class Util {

	public static <T, E> List<E> map(MapFunction<T, E> f, Iterable<T> i) {
		ArrayList<E> l = new ArrayList<>();
		Iterator<T> it = i.iterator();
		while (it.hasNext()) {
			l.add(f.apply(it.next()));
		}
		return l;
	}

	public static <E> List<E> asList(Iterator<E> i) {
		ArrayList<E> l = new ArrayList<>();
		while (i.hasNext()) {
			l.add(i.next());
		}
		return l;
	}

	public static interface MapFunction<T, E> {
		public E apply(T o);
	}

	public static void main(String[] args) {
		List<Integer> l = new ArrayList();
		for (int i = 0; i < 100; i++) {
			l.add(i);
		}
		List<String> ll = Util.map(new Util.MapFunction<Integer, String>() {
			public String apply(Integer o) {
				return o.toString();
			}
		}, l);
		for (String string : ll) {
			System.out.println(string);
		}
	}