最后如何访问多个Completablefuture Stage变量 [英] How to access multiple Completablefuture Stage variables at the end

问题描述

我正在尝试在completablefuture管道的末尾使用多个不同的变量.很难解释.这是我的示例:

Im trying to use multiple different variables at the end of a completablefuture pipe. Its hard to explain. Here is my example:

private void test(){
lib.getHumanFromDatabase().thenApplyAsync(human->{
        //returns one human from the database
        return human;
    }, executor).thenComposeAsync(humanFromDb-> {
        //Set new name of human
        humanFromDb.setName("NameOfHuman");
        //update human and return the new entity
        return lib.updateHumanInDatbase(humanFromDb);
    }, executor).thenComposeAsync(humanFromDb-> {
        //Then ask for his home
        return lib.getHomeOfHuman(humanFromDb);
    }).thenAcceptAsync(homeOfHuman-> {
        //So here at the end i want to access 
        //the variable humanFromDb AND
        //the variable homeOfHuman BUT
        //i only get homeOfHuman ...
    }, executor).handleAsync((ok, ex) -> {
        //Just for exception and so on
    }, executor);
}

我首先尝试将变量存储在方法内部的lambda之外，但在这里我得到的信息是变量必须是最终变量.是否有可能同时访问两个变量并最终返回它们，例如在某些UI窗口中?也许重要的是，两个变量的类型都不同.

I first tried to store the variables outside of lambda inside the method but here i get the information, that the variable has to be final. Is there any possebility to access both variables and the end to return them for example in some UI-Window or something? Maybe it is important, that both variables are of a different type.

也许不可能，我必须使用其他方法吗?我不知道...

Maybe it is not possible and i have to use a different approach? I have no clue ...

推荐答案

当只有单个依赖项链时，您可以使用单个方法链定义所有依赖阶段.否则，您必须将一个或多个阶段存储在一个变量中，即

You can define all dependent stages with a single method chain, when there is just a single chain of dependencies. Otherwise, you have to store one or more stages in a variable, i.e.

private void test() {    
    CompletableFuture<Human> humanFuture =
        lib.getHumanFromDatabase().thenApplyAsync(human -> {
            //returns one human from the database
            return human;
        }, executor).thenComposeAsync(humanFromDb -> {
            //Set new name of human
            humanFromDb.setName("NameOfHuman");
            //update human and return the new entity
            return lib.updateHumanInDatbase(humanFromDb);
        }, executor);

    humanFuture.thenComposeAsync(humanFromDb -> {
          //Then ask for his home
          return lib.getHomeOfHuman(humanFromDb);
      }).thenAcceptBothAsync(humanFuture, (humanFromDb, homeOfHuman) -> {
          //So here you can now access humanFromDb, homeOfHuman

      }, executor).handleAsync((ok, ex) -> {
          //Just for exception and so on

      }, executor);
}

因此，在这里，您只需要记住 humanFuture ，稍后将其传递给 thenAcceptBothAsync 即可创建一个依赖于 humanFuture 的阶段code>和提供 homeOfHuman 的未来(也取决于 humanFuture ).

So here, you just need to remember the humanFuture, to pass it later on to thenAcceptBothAsync to create a stage depending on both, the humanFuture and the future which provides the homeOfHuman (which also depends on humanFuture).

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