如何有选择地跳过 Flux 上的多个处理步骤

Question

我有从套接字接收的动态热数据流。我需要检查条件，如果值匹配，则跳转到步骤 3 并显示新消息。

    final Flux<Msg> msgs = Flux.generate(receiver);

    final Flux<Msg> processed = msgs
        .map(this::checkCondition)  //step1
        .map(remote::doLongRunning) //optional step2
        .map(this::processFurther)  //step3
 ...

    public Msg checkCondition(Msg msg) {
        if(doCheck(msg)){
            //is there a way to jump to step3 here ?
            return new OtherMsg(msg, "someAdditionalData")) 
        } else{
            return msg
        }
    }

我能想到的唯一选择 - 是将 Flux 分开并将其组装回来，有没有更干净的方法？

   final Flux<Msg> msgs = Flux.generate(receiver);

        final Flux<OtherMsg> checked = msgs
            .filter(this::doCheck) //step1
            .map(msg -> new OtherMsg(msg, "someAdditionalData"));

        final Flux<OtherMsg> unchecked = msgs
            .filter(msg -> !doCheck(msg)) //step1
            .map(remote::doLongRunning);  //optional step2

        Flux.merge(checked, unchecked)
            .map(this::processFurther)  //step3

Answer 1

您无法跳过步骤，但可以flatMap()与三元运算符一起使用以实现条件分支的形式：

final Flux<Msg> processed = msgs
        .flatMap(msg -> doCheck(msg)
            ? Mono.just(new OtherMsg(msg, "someAdditionalData")).map(remote::doLongRunning)
            : Mono.just(msg))
        .map(this::processFurther);

这样您就可以调用任何其他方法来操作三元表达式第一部分中的值，而第二部分将确保在doCheck()返回 false 时绕过它。processFurther()将在flatMap()调用后执行，因此无论如何都会执行。