GeneratorDemo.java

import static java.lang.System.out;
import com.google.code.jyield.*;

public class GeneratorDemo {
    public static void main(String args[]) {
        for(int n: YieldUtils.toIterable(take(25, sequenceOf(integers()))))
            out.println(n);
    }

    public static Generator<Integer> take(int count, Generator<Integer> source) {
        int[] cursorHolder = {0};
        return y ->
                source.generate(n -> {
                    if(cursorHolder[0] ++ < count) y.yield(n);
                });
    }

    public static Generator<Integer> sequenceOf(Generator<Integer> source) {
        return y ->  source.generate(n -> y.yield(n * n));
    }

    public static Generator<Integer> integers() {
        return y -> {
            for(int current = 1; current < Integer.MAX_VALUE; current ++)
                y.yield(current);
        };
    }
}