带有集合或列表的 Java 8 CompletableFuture.allOf(...)
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Java 8 CompletableFuture.allOf(...) with Collection or List
提问by therealrootuser
Java 8 has a function CompletableFuture.allOf(CompletableFuture<?>...cfs)that returns a CompletableFuturethat is completed when all the given futures complete.
Java 8 有一个函数CompletableFuture.allOf(CompletableFuture<?>...cfs)，它返回一个CompletableFuture在所有给定的期货完成时完成的函数。
However, I almost always am not dealing with an array of CompletableFutures, but instead have a List<CompletableFuture>. Of course, I can use the toArray()method, but this ends up being a bit of a pain to have to constantly convert back and forth between arrays and lists.
但是，我几乎总是不处理CompletableFutures数组，而是处理List<CompletableFuture>. 当然，我可以使用该toArray()方法，但最终不得不在数组和列表之间不断来回转换有点痛苦。
It would be really nice if there were a slick way get a CompletableFuture<List<T>>in exchange for a List<CompletableFuture<T>>, instead of constantly having to throw in an intermediary array creation. Does anyone know a way to do this in Java 8?
如果有一种巧妙的方式 get aCompletableFuture<List<T>>来交换 a List<CompletableFuture<T>>，而不是不断地投入中间数组创建，那将会非常好。有谁知道在 Java 8 中做到这一点的方法吗？
回答by Deepak
Unfortunately, to my knowledge CompletableFuture does not support collections.
不幸的是，据我所知 CompletableFuture 不支持集合。
You could do something like this to make the code a bit cleaner, but it essentially does the same thing
你可以做这样的事情来使代码更简洁，但它本质上做同样的事情
public <T> CompletableFuture<List<T>> allOf(List<CompletableFuture<T>> futuresList) {
CompletableFuture<Void> allFuturesResult =
CompletableFuture.allOf(futuresList.toArray(new CompletableFuture[futuresList.size()]));
return allFuturesResult.thenApply(v ->
futuresList.stream().
map(future -> future.join()).
collect(Collectors.<T>toList())
);
}
Found this very informative : http://www.nurkiewicz.com/2013/05/java-8-completablefuture-in-action.html
发现这非常有用：http: //www.nurkiewicz.com/2013/05/java-8-completablefuture-in-action.html
