public CompletableFuture apply()

in java/showcase/src/main/java/org/apache/flink/statefun/playground/java/showcase/part2/messaging/MessagingPrimitivesShowcaseFn.java [52:85]

18 lines of code
1 McCabe index (conditional complexity)


  public CompletableFuture<Void> apply(Context context, Message message) {
    // You send messages to functions simply by specifying the target function's typename
    // and the target instance id for that for function; StateFun handles the routing for you,
    // without the need of any means for service discovery.
    final Address targetAddress = new Address(TARGET_FN_TYPENAME, "target-instance-id");

    // you can directly send primitive type values as messages, ...
    context.send(MessageBuilder.forAddress(targetAddress).withValue(123).build());
    context.send(MessageBuilder.forAddress(targetAddress).withValue(true).build());
    context.send(MessageBuilder.forAddress(targetAddress).withValue("hello world!").build());
    context.send(MessageBuilder.forAddress(targetAddress).withValue(3.14159e+11f).build());
    context.send(MessageBuilder.forAddress(targetAddress).withValue(3.14159).build());
    context.send(MessageBuilder.forAddress(targetAddress).withValue(-19911108123046639L).build());

    // ... or, in general, a value of any custom defined type.
    context.send(
        MessageBuilder.forAddress(targetAddress)
            .withCustomType(USER_PROFILE_PROTOBUF_TYPE, UserProfile.getDefaultInstance())
            .build());

    // You can send messages to any function, including yourself!
    context.send(MessageBuilder.forAddress(context.self()).withValue("hello world!").build());

    // Additionally, you may ask StateFun to send out a message after a specified delay.
    // A common usage pattern is to send delayed messages to yourself to model timer triggers.
    context.sendAfter(
        Duration.ofMinutes(10),
        MessageBuilder.forAddress(context.self()).withValue("hello world!").build());

    // None of the above sends is a blocking operation.
    // All side-effects (such as messaging other functions) are collected and happen after this
    // method returns.
    return context.done();
  }