如何以reactor方式编写快捷循环

Question

我有一个像下面这样的非反应堆时尚代码，迭代一个检查器列表并快捷返回“BAD”如果任何检查器返回false：

public static String oldWay() {
    List<Checker> checkers = new ArrayList<>();
    String param = "blahblah";
    for (Checker checker : checkers) {
      if (!checker.check(param)) {
        return "BAD";
      }
    }
    return "GOOD";
}

interface Checker {
  boolean check(String str);
  Mono<Boolean> reactorCheck(String str);
}

如何将上面的代码转换为reactor时尚？

public static Mono<String> newWay() {
  // TODO
  return Mono.just("GOOD");
}

Answer 1

将它转过头并使用Flux#all(Predicate)，但输入Flux是你要测试的所有Checker中的一个：

//simplified Checker version for this example
interface Checker extends Predicate<String> {}

@Test
public void allChecks() {
    //given the checks you want to apply, as a Flux<Checker>...
    Checker lengthy = s -> s.length() > 3;
    Checker startsWithA = s -> s.toUpperCase().startsWith("A");

    Flux<Checker> checks = Flux.just(lengthy, startsWithA);

    //...and given the param String you want to check...
    String param = "Boooooh";
    //... verify that _all_ checkers match the predicate that "param passes the checker"
    Mono<String> allChecks = checks.all(checker -> checker.test(param))
        //and map that result to GOOD or BAD
          .map(allMatch -> allMatch ? "GOOD" : "BAD");

    StepVerifier.create(allChecks)
                .expectNext("BAD")
                .verifyComplete();

    //variant when multiple params to test:
    Flux<String> params = Flux.just("Booooh", "Always", "Ace");
    Flux<String> multiParamChecks = params.flatMap(p -> checks
            .all(checker -> checker.test(p))
            .map(valid -> p + (valid ? " GOOD" : " BAD"))
    );

    StepVerifier.create(multiParamChecks)
                .expectNext("Booooh BAD")
                .expectNext("Always GOOD")
                .expectNext("Ace BAD")
                .verifyComplete();
}