ForEachLoopWithIndex.java

package de.aeffle.for_each_with_counter;


import com.google.common.collect.ImmutableList;
import org.junit.Test;

import java.util.Iterator;
import java.util.List;

public class ForEachLoopWithIndex {

    @Test
    public void blubb() {
        List<String> strings = ImmutableList.of("one", "two", "three");

        for (String string : strings) {
            System.out.println("String: " + string);
        }

        System.out.println("---");

        for (Index<String> each: With.index(strings)) {
            System.out.println("Index: " + each.index);
            System.out.println("Value: " + each.value);
            System.out.println("---");
        }
    }
}


class Index<T> {
    public final T value;
    public final int index;

    public Index(int index, T value) {
        this.index = index;
        this.value = value;
    }
}

class With {
    public static <T> Iterable<Index<T>> index(final List<T> list) {
        return () -> new Iterator<Index<T>>() {
            int index = 0;
            Iterator<T> iterator = list.iterator();

            public boolean hasNext() {
                return iterator.hasNext();
            }

            public Index<T> next() {
                return new Index( index++, iterator.next());
            }
        };
    }
}