Java 8 Completable Futures allOf different data types

Question

I have 3 CompletableFutures all 3 returning different data types.

I am looking to create a result object that is a composition of the result returned by all the 3 fu

Answer 1

Another way to handle this if you don't want to declare as many variables is to use thenCombine or thenCombineAsync to chain your futures together.

public CompletableFuture getResultClassD()
{
  return CompletableFuture.supplyAsync(ClassD::new)
    .thenCombine(CompletableFuture.supplyAsync(service::getClassA), (d, a) -> {
      d.setClassA(a);
      return d;
    })
    .thenCombine(CompletableFuture.supplyAsync(service::getClassB), (d, b) -> {
      d.setClassB(b);
      return d;
    })
    .thenCombine(CompletableFuture.supplyAsync(service::getClassC), (d, c) -> {
      d.setClassC(c);
      return d;
    });
}

The getters will still be fired off asynchronously and the results executed in order. It's basically another syntax option to get the same result.