如何在Java中实现Function1（其compose和andThen方法）？

Question

I am working with Akka Java API's, in one of the actors I want to receive a callback and process it on completion.

I want to achieve something like:

Future future = Patterns.ask(actorRefMap.get(order.getInstrument()), order, 500);
future.onComplete(getSender().tell(String.format("{} order processed for instrument {} with price {}", order.getOrderType(), order.getInstrument(), order.getPrice()), getSelf()), getContext().dispatcher());

With my current code I am getting error wrong first argument, Found 'void' required 'scala.Function1'. How do we implement the scala.Function1 in Java?

Answer 1

You need to pass it as a function:

Future future = Patterns.ask(actorRefMap.get(order.getInstrument()), order, 500);
future.onComplete(() -> getSender().tell(String.format("{} order processed for instrument {} with price {}", order.getOrderType(), order.getInstrument(), order.getPrice()), getSelf()), getContext().dispatcher());

... the essential part is:

future.onComplete(() -> ...)

instead of

future.onComplete(...)

And if it requires scala.Function1 instead of java.util.Function , make sure you import the Java DSL ( akka.actor.typed.javadsl.AskPattern ), not the Scala DSL ...