65 lines
2.1 KiB
Java
65 lines
2.1 KiB
Java
package controllers;
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import akka.actor.ActorSystem;
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import javax.inject.*;
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import play.*;
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import play.mvc.*;
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import java.util.concurrent.Executor;
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import java.util.concurrent.CompletableFuture;
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import java.util.concurrent.CompletionStage;
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import java.util.concurrent.TimeUnit;
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import scala.concurrent.duration.Duration;
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import scala.concurrent.ExecutionContextExecutor;
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/**
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* This controller contains an action that demonstrates how to write
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* simple asynchronous code in a controller. It uses a timer to
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* asynchronously delay sending a response for 1 second.
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*
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* @param actorSystem We need the {@link ActorSystem}'s
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* {@link Scheduler} to run code after a delay.
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* @param exec We need a Java {@link Executor} to apply the result
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* of the {@link CompletableFuture} and a Scala
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* {@link ExecutionContext} so we can use the Akka {@link Scheduler}.
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* An {@link ExecutionContextExecutor} implements both interfaces.
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*/
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@Singleton
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public class AsyncController extends Controller {
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private final ActorSystem actorSystem;
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private final ExecutionContextExecutor exec;
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@Inject
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public AsyncController(ActorSystem actorSystem, ExecutionContextExecutor exec) {
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this.actorSystem = actorSystem;
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this.exec = exec;
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}
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/**
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* An action that returns a plain text message after a delay
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* of 1 second.
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* <p>
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* The configuration in the <code>routes</code> file means that this method
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* will be called when the application receives a <code>GET</code> request with
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* a path of <code>/message</code>.
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*/
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public CompletionStage<Result> message() {
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return getFutureMessage(1, TimeUnit.SECONDS).thenApplyAsync(Results::ok, exec);
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}
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private CompletionStage<String> getFutureMessage(long time, TimeUnit timeUnit) {
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CompletableFuture<String> future = new CompletableFuture<>();
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actorSystem.scheduler().scheduleOnce(
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Duration.create(time, timeUnit),
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() -> future.complete("Hi!"),
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exec
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);
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return future;
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}
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}
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