Package akka.pattern

Class Patterns

  • public class Patterns
extends java.lang.Object
    Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target actor needs to send the result to the sender reference provided.

    The Future will be completed with an AskTimeoutException after the given timeout has expired; this is independent from any timeout applied while awaiting a result for this future (i.e. in Await.result(..., timeout)). A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

    Warning: When using future callbacks, inside actors you need to carefully avoid closing over the containing actor’s object, i.e. do not call methods or access mutable state on the enclosing actor from within the callback. This would break the actor encapsulation and may introduce synchronization bugs and race conditions because the callback will be scheduled concurrently to the enclosing actor. Unfortunately there is not yet a way to detect these illegal accesses at compile time.

    Recommended usage: 

    
   final Future<Object> f = Patterns.ask(worker, request, timeout);
   f.onSuccess(new Procedure<Object>() {
     public void apply(Object o) {
       nextActor.tell(new EnrichedResult(request, o));
     }
   });

    • Constructor Summary

      Constructors 
      Constructor Description
      Patterns()  

    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      static <T> java.util.concurrent.CompletionStage<T> after​(java.time.Duration duration, Scheduler scheduler, scala.concurrent.ExecutionContext context, java.util.concurrent.Callable<java.util.concurrent.CompletionStage<T>> value)
      Returns a CompletionStage that will be completed with the success or failure of the provided Callable after the specified duration.
      static <T> java.util.concurrent.CompletionStage<T> after​(java.time.Duration duration, Scheduler scheduler, scala.concurrent.ExecutionContext context, java.util.concurrent.CompletionStage<T> value)
      Deprecated.
      Use the overloaded one which accepts a Callable of CompletionStage instead.
      static <T> scala.concurrent.Future<T> after​(scala.concurrent.duration.FiniteDuration duration, Scheduler scheduler, scala.concurrent.ExecutionContext context, java.util.concurrent.Callable<scala.concurrent.Future<T>> value)
      Returns a Future that will be completed with the success or failure of the provided Callable after the specified duration.
      static <T> scala.concurrent.Future<T> after​(scala.concurrent.duration.FiniteDuration duration, Scheduler scheduler, scala.concurrent.ExecutionContext context, scala.concurrent.Future<T> value)
      Deprecated.
      Use the overload one which accepts a Callable of Future instead.
      static scala.concurrent.Future<java.lang.Object> ask​(ActorRef actor, java.lang.Object message, long timeoutMillis)
      Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target actor needs to send the result to the sender reference provided.
      static scala.concurrent.Future<java.lang.Object> ask​(ActorRef actor, java.lang.Object message, Timeout timeout)  
      static java.util.concurrent.CompletionStage<java.lang.Object> ask​(ActorRef actor, java.lang.Object message, java.time.Duration timeout)
      Java API for akka.pattern.ask: Sends a message asynchronously and returns a CompletionStage holding the eventual reply message; this means that the target actor needs to send the result to the sender reference provided.
      static scala.concurrent.Future<java.lang.Object> ask​(ActorSelection selection, java.lang.Object message, long timeoutMillis)
      Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target ActorSelection needs to send the result to the sender reference provided.
      static scala.concurrent.Future<java.lang.Object> ask​(ActorSelection selection, java.lang.Object message, Timeout timeout)
      Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target ActorSelection needs to send the result to the sender reference provided.
      static java.util.concurrent.CompletionStage<java.lang.Object> ask​(ActorSelection selection, java.lang.Object message, java.time.Duration timeout)
      Java API for akka.pattern.ask: Sends a message asynchronously and returns a CompletionStage holding the eventual reply message; this means that the target ActorSelection needs to send the result to the sender reference provided.
      static java.util.concurrent.CompletionStage<java.lang.Object> askWithReplyTo​(ActorRef actor, Function<ActorRef,​java.lang.Object> messageFactory, java.time.Duration timeout)
      A variation of ask which allows to implement "replyTo" pattern by including sender reference in message.
      static scala.concurrent.Future<java.lang.Object> askWithReplyTo​(ActorRef actor, Function<ActorRef,​java.lang.Object> messageFactory, long timeoutMillis)
      A variation of ask which allows to implement "replyTo" pattern by including sender reference in message.
      static scala.concurrent.Future<java.lang.Object> askWithReplyTo​(ActorRef actor, Function<ActorRef,​java.lang.Object> messageFactory, Timeout timeout)
      A variation of ask which allows to implement "replyTo" pattern by including sender reference in message.
      static scala.concurrent.Future<java.lang.Object> askWithReplyTo​(ActorSelection selection, Function<ActorRef,​java.lang.Object> messageFactory, long timeoutMillis)
      A variation of ask which allows to implement "replyTo" pattern by including sender reference in message.
      static java.util.concurrent.CompletionStage<java.lang.Object> askWithReplyTo​(ActorSelection selection, Function<ActorRef,​java.lang.Object> messageFactory, java.time.Duration timeout)
      A variation of ask which allows to implement "replyTo" pattern by including sender reference in message.
      static java.util.concurrent.CompletionStage<java.lang.Boolean> gracefulStop​(ActorRef target, java.time.Duration timeout)
      Returns a CompletionStage that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.
      static java.util.concurrent.CompletionStage<java.lang.Boolean> gracefulStop​(ActorRef target, java.time.Duration timeout, java.lang.Object stopMessage)
      Returns a CompletionStage that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.
      static scala.concurrent.Future<java.lang.Boolean> gracefulStop​(ActorRef target, scala.concurrent.duration.FiniteDuration timeout)
      Returns a Future that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.
      static scala.concurrent.Future<java.lang.Boolean> gracefulStop​(ActorRef target, scala.concurrent.duration.FiniteDuration timeout, java.lang.Object stopMessage)
      Returns a Future that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.
      static <T> PipeToSupport.PipeableCompletionStage<T> pipe​(java.util.concurrent.CompletionStage<T> future, scala.concurrent.ExecutionContext context)
      When this CompletionStage finishes, send its result to the given ActorRef or ActorSelection.
      static <T> PipeToSupport.PipeableFuture<T> pipe​(scala.concurrent.Future<T> future, scala.concurrent.ExecutionContext context)
      Register an onComplete callback on this Future to send the result to the given ActorRef or ActorSelection.
      static <T> java.util.concurrent.CompletionStage<T> retry​(java.util.concurrent.Callable<java.util.concurrent.CompletionStage<T>> attempt, int attempts, java.time.Duration delay, Scheduler scheduler, scala.concurrent.ExecutionContext ec)
      Returns an internally retrying CompletionStage The first attempt will be made immediately, and each subsequent attempt will be made after 'delay'.
      static <T> scala.concurrent.Future<T> retry​(java.util.concurrent.Callable<scala.concurrent.Future<T>> attempt, int attempts, scala.concurrent.duration.FiniteDuration delay, Scheduler scheduler, scala.concurrent.ExecutionContext context)
      Returns an internally retrying Future The first attempt will be made immediately, and each subsequent attempt will be made after 'delay'.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • Patterns

        public Patterns()

    • Method Detail

      • ask

        public static scala.concurrent.Future<java.lang.Object> ask​(ActorRef actor,
                                                            java.lang.Object message,
                                                            Timeout timeout)

      • ask

        public static java.util.concurrent.CompletionStage<java.lang.Object> ask​(ActorRef actor,
                                                                         java.lang.Object message,
                                                                         java.time.Duration timeout)
        Java API for akka.pattern.ask: Sends a message asynchronously and returns a CompletionStage holding the eventual reply message; this means that the target actor needs to send the result to the sender reference provided.

        The CompletionStage will be completed with an AskTimeoutException after the given timeout has expired; this is independent from any timeout applied while awaiting a result for this future (i.e. in Await.result(..., timeout)). A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

        Warning: When using future callbacks, inside actors you need to carefully avoid closing over the containing actor&rsquo;s object, i.e. do not call methods or access mutable state on the enclosing actor from within the callback. This would break the actor encapsulation and may introduce synchronization bugs and race conditions because the callback will be scheduled concurrently to the enclosing actor. Unfortunately there is not yet a way to detect these illegal accesses at compile time.

        Recommended usage: 

        
   final CompletionStage<Object> f = Patterns.ask(worker, request, duration);
   f.thenRun(result -> nextActor.tell(new EnrichedResult(request, result)));
        Parameters:
        actor - (undocumented)
        message - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • askWithReplyTo

        public static scala.concurrent.Future<java.lang.Object> askWithReplyTo​(ActorRef actor,
                                                                       Function<ActorRef,​java.lang.Object> messageFactory,
                                                                       Timeout timeout)
        A variation of ask which allows to implement "replyTo" pattern by including sender reference in message. 

        
 final Future<Object> f = Patterns.askWithReplyTo(
   worker,
   replyTo -> new Request(replyTo),
   timeout);
        Parameters:
        actor - (undocumented)
        messageFactory - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • askWithReplyTo

        public static java.util.concurrent.CompletionStage<java.lang.Object> askWithReplyTo​(ActorRef actor,
                                                                                    Function<ActorRef,​java.lang.Object> messageFactory,
                                                                                    java.time.Duration timeout)
        A variation of ask which allows to implement "replyTo" pattern by including sender reference in message. 

        
 final CompletionStage<Object> f = Patterns.askWithReplyTo(
   worker,
   askSender -> new Request(askSender),
   timeout);

        Parameters:
        actor - the actor to be asked
        messageFactory - function taking an actor ref and returning the message to be sent
        timeout - the timeout for the response before failing the returned completion stage
        Returns:
        (undocumented)

      • ask

        public static scala.concurrent.Future<java.lang.Object> ask​(ActorRef actor,
                                                            java.lang.Object message,
                                                            long timeoutMillis)
        Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target actor needs to send the result to the sender reference provided.

        The Future will be completed with an AskTimeoutException after the given timeout has expired; this is independent from any timeout applied while awaiting a result for this future (i.e. in Await.result(..., timeout)). A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

        Warning: When using future callbacks, inside actors you need to carefully avoid closing over the containing actor&rsquo;s object, i.e. do not call methods or access mutable state on the enclosing actor from within the callback. This would break the actor encapsulation and may introduce synchronization bugs and race conditions because the callback will be scheduled concurrently to the enclosing actor. Unfortunately there is not yet a way to detect these illegal accesses at compile time.

        Recommended usage: 

        
   final Future<Object> f = Patterns.ask(worker, request, timeout);
   f.onSuccess(new Procedure<Object>() {
     public void apply(Object o) {
       nextActor.tell(new EnrichedResult(request, o));
     }
   });
        Parameters:
        actor - (undocumented)
        message - (undocumented)
        timeoutMillis - (undocumented)
        Returns:
        (undocumented)

      • askWithReplyTo

        public static scala.concurrent.Future<java.lang.Object> askWithReplyTo​(ActorRef actor,
                                                                       Function<ActorRef,​java.lang.Object> messageFactory,
                                                                       long timeoutMillis)
        A variation of ask which allows to implement "replyTo" pattern by including sender reference in message. 

        
 final Future<Object> f = Patterns.askWithReplyTo(
   worker,
   replyTo -> new Request(replyTo),
   timeout);
        Parameters:
        actor - (undocumented)
        messageFactory - (undocumented)
        timeoutMillis - (undocumented)
        Returns:
        (undocumented)

      • ask

        public static scala.concurrent.Future<java.lang.Object> ask​(ActorSelection selection,
                                                            java.lang.Object message,
                                                            Timeout timeout)
        Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target ActorSelection needs to send the result to the sender reference provided.

        The Future will be completed with an AskTimeoutException after the given timeout has expired; this is independent from any timeout applied while awaiting a result for this future (i.e. in Await.result(..., timeout)). A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

        Warning: When using future callbacks, inside actors you need to carefully avoid closing over the containing actor&rsquo;s object, i.e. do not call methods or access mutable state on the enclosing actor from within the callback. This would break the actor encapsulation and may introduce synchronization bugs and race conditions because the callback will be scheduled concurrently to the enclosing actor. Unfortunately there is not yet a way to detect these illegal accesses at compile time.

        Recommended usage: 

        
   final Future<Object> f = Patterns.ask(selection, request, timeout);
   f.onSuccess(new Procedure<Object>() {
     public void apply(Object o) {
       nextActor.tell(new EnrichedResult(request, o));
     }
   });
        Parameters:
        selection - (undocumented)
        message - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • ask

        public static java.util.concurrent.CompletionStage<java.lang.Object> ask​(ActorSelection selection,
                                                                         java.lang.Object message,
                                                                         java.time.Duration timeout)
        Java API for akka.pattern.ask: Sends a message asynchronously and returns a CompletionStage holding the eventual reply message; this means that the target ActorSelection needs to send the result to the sender reference provided.

        The CompletionStage will be completed with an AskTimeoutException after the given timeout has expired; this is independent from any timeout applied while awaiting a result for this future (i.e. in Await.result(..., timeout)). A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

        Warning: When using future callbacks, inside actors you need to carefully avoid closing over the containing actor&rsquo;s object, i.e. do not call methods or access mutable state on the enclosing actor from within the callback. This would break the actor encapsulation and may introduce synchronization bugs and race conditions because the callback will be scheduled concurrently to the enclosing actor. Unfortunately there is not yet a way to detect these illegal accesses at compile time.

        Recommended usage: 

        
   final CompletionStage<Object> f = Patterns.ask(selection, request, duration);
   f.thenRun(result -> nextActor.tell(new EnrichedResult(request, result)));
        Parameters:
        selection - (undocumented)
        message - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • ask

        public static scala.concurrent.Future<java.lang.Object> ask​(ActorSelection selection,
                                                            java.lang.Object message,
                                                            long timeoutMillis)
        Java API for akka.pattern.ask: Sends a message asynchronously and returns a Future holding the eventual reply message; this means that the target ActorSelection needs to send the result to the sender reference provided.

        The Future will be completed with an AskTimeoutException after the given timeout has expired; this is independent from any timeout applied while awaiting a result for this future (i.e. in Await.result(..., timeout)). A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

        Warning: When using future callbacks, inside actors you need to carefully avoid closing over the containing actor&rsquo;s object, i.e. do not call methods or access mutable state on the enclosing actor from within the callback. This would break the actor encapsulation and may introduce synchronization bugs and race conditions because the callback will be scheduled concurrently to the enclosing actor. Unfortunately there is not yet a way to detect these illegal accesses at compile time.

        Recommended usage: 

        
   final Future<Object> f = Patterns.ask(selection, request, timeout);
   f.onSuccess(new Procedure<Object>() {
     public void apply(Object o) {
       nextActor.tell(new EnrichedResult(request, o));
     }
   });
        Parameters:
        selection - (undocumented)
        message - (undocumented)
        timeoutMillis - (undocumented)
        Returns:
        (undocumented)

      • askWithReplyTo

        public static scala.concurrent.Future<java.lang.Object> askWithReplyTo​(ActorSelection selection,
                                                                       Function<ActorRef,​java.lang.Object> messageFactory,
                                                                       long timeoutMillis)
        A variation of ask which allows to implement "replyTo" pattern by including sender reference in message. 

        
 final Future<Object> f = Patterns.askWithReplyTo(
   selection,
   replyTo -> new Request(replyTo),
   timeout);
        Parameters:
        selection - (undocumented)
        messageFactory - (undocumented)
        timeoutMillis - (undocumented)
        Returns:
        (undocumented)

      • askWithReplyTo

        public static java.util.concurrent.CompletionStage<java.lang.Object> askWithReplyTo​(ActorSelection selection,
                                                                                    Function<ActorRef,​java.lang.Object> messageFactory,
                                                                                    java.time.Duration timeout)
        A variation of ask which allows to implement "replyTo" pattern by including sender reference in message. 

        
 final CompletionStage<Object> f = Patterns.askWithReplyTo(
   selection,
   replyTo -> new Request(replyTo),
   timeout);
        Parameters:
        selection - (undocumented)
        messageFactory - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • pipe

        public static <T> PipeToSupport.PipeableFuture<T> pipe​(scala.concurrent.Future<T> future,
                                                       scala.concurrent.ExecutionContext context)
        Register an onComplete callback on this Future to send the result to the given ActorRef or ActorSelection. Returns the original Future to allow method chaining. If the future was completed with failure it is sent as a Status.Failure to the recipient.

        Recommended usage example: 

        
   final Future<Object> f = Patterns.ask(worker, request, timeout);
   // apply some transformation (i.e. enrich with request info)
   final Future<Object> transformed = f.map(new akka.japi.Function<Object, Object>() { ... });
   // send it on to the next operator
   Patterns.pipe(transformed, context).to(nextActor);
        Parameters:
        future - (undocumented)
        context - (undocumented)
        Returns:
        (undocumented)

      • pipe

        public static <T> PipeToSupport.PipeableCompletionStage<T> pipe​(java.util.concurrent.CompletionStage<T> future,
                                                                scala.concurrent.ExecutionContext context)
        When this CompletionStage finishes, send its result to the given ActorRef or ActorSelection. Returns the original CompletionStage to allow method chaining. If the future was completed with failure it is sent as a Status.Failure to the recipient.

        Recommended usage example: 

        
   final CompletionStage<Object> f = Patterns.ask(worker, request, timeout);
   // apply some transformation (i.e. enrich with request info)
   final CompletionStage<Object> transformed = f.thenApply(result -> { ... });
   // send it on to the next operator
   Patterns.pipe(transformed, context).to(nextActor);
        Parameters:
        future - (undocumented)
        context - (undocumented)
        Returns:
        (undocumented)

      • gracefulStop

        public static scala.concurrent.Future<java.lang.Boolean> gracefulStop​(ActorRef target,
                                                                      scala.concurrent.duration.FiniteDuration timeout)
        Returns a Future that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.

        Useful when you need to wait for termination or compose ordered termination of several actors.

        If the target actor isn't terminated within the timeout the Future is completed with failure AskTimeoutException.

        Parameters:
        target - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • gracefulStop

        public static java.util.concurrent.CompletionStage<java.lang.Boolean> gracefulStop​(ActorRef target,
                                                                                   java.time.Duration timeout)
        Returns a CompletionStage that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.

        Useful when you need to wait for termination or compose ordered termination of several actors.

        If the target actor isn't terminated within the timeout the CompletionStage is completed with failure AskTimeoutException.

        Parameters:
        target - (undocumented)
        timeout - (undocumented)
        Returns:
        (undocumented)

      • gracefulStop

        public static scala.concurrent.Future<java.lang.Boolean> gracefulStop​(ActorRef target,
                                                                      scala.concurrent.duration.FiniteDuration timeout,
                                                                      java.lang.Object stopMessage)
        Returns a Future that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.

        Useful when you need to wait for termination or compose ordered termination of several actors.

        If you want to invoke specialized stopping logic on your target actor instead of PoisonPill, you can pass your stop command as stopMessage parameter

        If the target actor isn't terminated within the timeout the Future is completed with failure AskTimeoutException.

        Parameters:
        target - (undocumented)
        timeout - (undocumented)
        stopMessage - (undocumented)
        Returns:
        (undocumented)

      • gracefulStop

        public static java.util.concurrent.CompletionStage<java.lang.Boolean> gracefulStop​(ActorRef target,
                                                                                   java.time.Duration timeout,
                                                                                   java.lang.Object stopMessage)
        Returns a CompletionStage that will be completed with success (value true) when existing messages of the target actor has been processed and the actor has been terminated.

        Useful when you need to wait for termination or compose ordered termination of several actors.

        If you want to invoke specialized stopping logic on your target actor instead of PoisonPill, you can pass your stop command as stopMessage parameter

        If the target actor isn't terminated within the timeout the CompletionStage is completed with failure AskTimeoutException.

        Parameters:
        target - (undocumented)
        timeout - (undocumented)
        stopMessage - (undocumented)
        Returns:
        (undocumented)

      • after

        public static <T> scala.concurrent.Future<T> after​(scala.concurrent.duration.FiniteDuration duration,
                                                   Scheduler scheduler,
                                                   scala.concurrent.ExecutionContext context,
                                                   java.util.concurrent.Callable<scala.concurrent.Future<T>> value)
        Returns a Future that will be completed with the success or failure of the provided Callable after the specified duration.
        Parameters:
        duration - (undocumented)
        scheduler - (undocumented)
        context - (undocumented)
        value - (undocumented)
        Returns:
        (undocumented)

      • after

        public static <T> java.util.concurrent.CompletionStage<T> after​(java.time.Duration duration,
                                                                Scheduler scheduler,
                                                                scala.concurrent.ExecutionContext context,
                                                                java.util.concurrent.Callable<java.util.concurrent.CompletionStage<T>> value)
        Returns a CompletionStage that will be completed with the success or failure of the provided Callable after the specified duration.
        Parameters:
        duration - (undocumented)
        scheduler - (undocumented)
        context - (undocumented)
        value - (undocumented)
        Returns:
        (undocumented)

      • after

        public static <T> scala.concurrent.Future<T> after​(scala.concurrent.duration.FiniteDuration duration,
                                                   Scheduler scheduler,
                                                   scala.concurrent.ExecutionContext context,
                                                   scala.concurrent.Future<T> value)
        Deprecated.
        Use the overload one which accepts a Callable of Future instead. Since 2.5.22.
        Returns a Future that will be completed with the success or failure of the provided Callable after the specified duration.
        Parameters:
        duration - (undocumented)
        scheduler - (undocumented)
        context - (undocumented)
        value - (undocumented)
        Returns:
        (undocumented)

      • after

        public static <T> java.util.concurrent.CompletionStage<T> after​(java.time.Duration duration,
                                                                Scheduler scheduler,
                                                                scala.concurrent.ExecutionContext context,
                                                                java.util.concurrent.CompletionStage<T> value)
        Deprecated.
        Use the overloaded one which accepts a Callable of CompletionStage instead. Since 2.5.22.
        Returns a CompletionStage that will be completed with the success or failure of the provided value after the specified duration.
        Parameters:
        duration - (undocumented)
        scheduler - (undocumented)
        context - (undocumented)
        value - (undocumented)
        Returns:
        (undocumented)

      • retry

        public static <T> scala.concurrent.Future<T> retry​(java.util.concurrent.Callable<scala.concurrent.Future<T>> attempt,
                                                   int attempts,
                                                   scala.concurrent.duration.FiniteDuration delay,
                                                   Scheduler scheduler,
                                                   scala.concurrent.ExecutionContext context)
        Returns an internally retrying Future The first attempt will be made immediately, and each subsequent attempt will be made after 'delay'. A scheduler (eg context.system.scheduler) must be provided to delay each retry If attempts are exhausted the returned future is simply the result of invoking attempt. Note that the attempt function will be invoked on the given execution context for subsequent tries and therefore must be thread safe (not touch unsafe mutable state).
        Parameters:
        attempt - (undocumented)
        attempts - (undocumented)
        delay - (undocumented)
        scheduler - (undocumented)
        context - (undocumented)
        Returns:
        (undocumented)

      • retry

        public static <T> java.util.concurrent.CompletionStage<T> retry​(java.util.concurrent.Callable<java.util.concurrent.CompletionStage<T>> attempt,
                                                                int attempts,
                                                                java.time.Duration delay,
                                                                Scheduler scheduler,
                                                                scala.concurrent.ExecutionContext ec)
        Returns an internally retrying CompletionStage The first attempt will be made immediately, and each subsequent attempt will be made after 'delay'. A scheduler (eg context.system.scheduler) must be provided to delay each retry If attempts are exhausted the returned completion operator is simply the result of invoking attempt. Note that the attempt function will be invoked on the given execution context for subsequent tries and therefore must be thread safe (not touch unsafe mutable state).
        Parameters:
        attempt - (undocumented)
        attempts - (undocumented)
        delay - (undocumented)
        scheduler - (undocumented)
        ec - (undocumented)
        Returns:
        (undocumented)