WidgetAndArticles.java

package blog;

import java.util.List;

import rx.Observable;

public class WidgetAndArticles {
    static final class Widget {
        String articleName;
        String articleUrl;
        int type;
        public Widget(int type) {
            this.type = type;
        }
        @Override
        public String toString() {
            return "Widget [articleName=" + articleName + ", articleUrl="
                    + articleUrl + ", type=" + type + "]";
        }
        
    }
    static final class Article {
        @Override
        public String toString() {
            return "Article [parent=" + parent + ", name=" + name + ", url="
                    + url + "]";
        }
        Widget parent;
        String name;
        String url;
    }
    
    static Observable<List<Widget>> getWidgets(String token) {
        return Observable.range(1, 10).map(Widget::new).toList();
    }
    
    static Observable<List<Article>> getArticles(String token, int type) {
        return Observable.range(1, 3).map(i -> {
            Article a = new Article();
            a.name = "Article " + i + " for type " + type;
            a.url = "http://.../" + type + "/" + i;
            return a;
        }).toList();
    }
    
    public static void main(String[] args) {
        getWidgets("token")
        .flatMapIterable(w -> w)
        .flatMap(w -> 
            getArticles("token", w.type)
            .flatMapIterable(a -> a)
            .doOnNext(a -> System.out.println("Inserting " + a))
            .doOnNext(a -> {
                 w.articleName = a.name;
                 w.articleUrl = a.url;
            })
            .takeLast(1)
            .map(a -> w)
         )
        .toList()
        .subscribe(System.out::println);
    }
}