よくある Observable の入れ子ができない頭の硬さ乙

なぜか長ったらしくなる Observable のネスト.


Observable.just("yo")
    .flatMap(s -> Observable.range(0, 100))
    .subscribe(integer -> Ln.d("Here's an Integer(%s), but how do I access that juicy String?", integer));

Passing composite data through flatMap and similar operators without creating container objects · Issue #2931 · ReactiveX/RxJava

よくあるくせに綺麗に書けない.

そんなわたし乙.

lambda も絡めてゆっくりと眺める.

元.


Observable.just("yo")
    .flatMap(new Func1<String, Observable<? extends Integer>>() {
      @Override public Observable<? extends Integer> call(String s) {
        return Observable.range(0, 100);
      }
    })
    .map(new Func1<Integer, String>() {
      @Override public String call(Integer integer) {
        return String.format("Here's an Integer(%s), but how do I access that juicy String?", integer);
      }
    })
    .subscribe(new Action1<String>() {
      @Override public void call(String x) {
        System.out.println(x);
      }
    });

flatMap(Func1, Func2) でやる場合.


Observable.just("yo")
    .flatMap(new Func1<String, Observable<? extends Integer>>() {
      @Override public Observable<? extends Integer> call(String s) {
        return Observable.range(0, 100);
      }
    }, new Func2<String, Integer, String>() {
      @Override public String call(String s, Integer integer) {
        return String.format("Here's an Integer(%s), with String(%s)", integer, s);
      }
    })
    .subscribe(new Action1<String>() {
      @Override public void call(String x) {
        System.out.println(x);
      }
    });

flatmap に map を入れ子でやる場合.


Observable.just("yo")
    .flatMap(new Func1<String, Observable<? extends String>>() {
      @Override public Observable<? extends String> call(String s) {
        return Observable.range(0, 100)
            .map(new Func1<Integer, String>() {
              @Override public String call(Integer integer) {
                return String.format("Here's an Integer(%s), with String(%s)", integer, s);
              }
            });
      }
    })
    .subscribe(new Action1<String>() {
      @Override public void call(String x) {
        System.out.println(x);
      }
    });
  }

lambda へ

元.


Observable.just("yo")
    .flatMap(s -> Observable.range(0, 100))
    .map(integer -> String.format("Here's an Integer(%s), but how do I access that juicy String?", integer))
    .subscribe(System.out::println);

flatMap(Func1, Func2) でやる場合.


Observable.just("yo")
    .flatMap(s -> Observable.range(0, 100),
        (s, integer) -> String.format("Here's an Integer(%s), with String(%s)", integer, s))
    .subscribe(System.out::println);

flatmap に map を入れ子でやる場合.


Observable.just("yo")
    .flatMap(s -> Observable.range(0, 100)
        .map(integer -> String.format("Here's an Integer(%s), with String(%s)", integer, s)))
    .subscribe(System.out::println);