content: /*
   * Copyright (C) 2017-2025 Lightbend Inc. <https://www.lightbend.com>
   */
  
  package jdocs.akka.typed;
  
  // #imports
  import akka.actor.typed.ActorRef;
  import akka.actor.typed.ActorSystem;
  import akka.actor.typed.Behavior;
  import akka.actor.typed.javadsl.AbstractBehavior;
  import akka.actor.typed.javadsl.ActorContext;
  import akka.actor.typed.javadsl.Behaviors;
  import akka.actor.typed.javadsl.Receive;
  import akka.actor.typed.javadsl.ReceiveBuilder;
  
  // #imports
  
  import akka.actor.typed.Terminated;
  
  import java.io.UnsupportedEncodingException;
  import java.net.URLEncoder;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.List;
  
  public interface OOIntroTest {
  
    // #chatroom-behavior
    public class ChatRoom {
      // #chatroom-behavior
      // #chatroom-protocol
      static interface RoomCommand {}
  
      public static final class GetSession implements RoomCommand {
        public final String screenName;
        public final ActorRef<SessionEvent> replyTo;
  
        public GetSession(String screenName, ActorRef<SessionEvent> replyTo) {
          this.screenName = screenName;
          this.replyTo = replyTo;
        }
      }
      // #chatroom-protocol
      // #chatroom-behavior
      private static final class PublishSessionMessage implements RoomCommand {
        public final String screenName;
        public final String message;
  
        public PublishSessionMessage(String screenName, String message) {
          this.screenName = screenName;
          this.message = message;
        }
      }
      // #chatroom-behavior
      // #chatroom-protocol
  
      static interface SessionEvent {}
  
      public static final class SessionGranted implements SessionEvent {
        public final ActorRef<PostMessage> handle;
  
        public SessionGranted(ActorRef<PostMessage> handle) {
          this.handle = handle;
        }
      }
  
      public static final class SessionDenied implements SessionEvent {
        public final String reason;
  
        public SessionDenied(String reason) {
          this.reason = reason;
        }
      }
  
      public static final class MessagePosted implements SessionEvent {
        public final String screenName;
        public final String message;
  
        public MessagePosted(String screenName, String message) {
          this.screenName = screenName;
          this.message = message;
        }
      }
  
      static interface SessionCommand {}
  
      public static final class PostMessage implements SessionCommand {
        public final String message;
  
        public PostMessage(String message) {
          this.message = message;
        }
      }
  
      private static final class NotifyClient implements SessionCommand {
        final MessagePosted message;
  
        NotifyClient(MessagePosted message) {
          this.message = message;
        }
      }
      // #chatroom-protocol
      // #chatroom-behavior
  
      public static Behavior<RoomCommand> create() {
        return Behaviors.setup(ChatRoomBehavior::new);
      }
  
      public static class ChatRoomBehavior extends AbstractBehavior<RoomCommand> {
        final List<ActorRef<SessionCommand>> sessions = new ArrayList<>();
  
        private ChatRoomBehavior(ActorContext<RoomCommand> context) {
          super(context);
        }
  
        @Override
        public Receive<RoomCommand> createReceive() {
          ReceiveBuilder<RoomCommand> builder = newReceiveBuilder();
  
          builder.onMessage(GetSession.class, this::onGetSession);
          builder.onMessage(PublishSessionMessage.class, this::onPublishSessionMessage);
  
          return builder.build();
        }
  
        private Behavior<RoomCommand> onGetSession(GetSession getSession)
            throws UnsupportedEncodingException {
          ActorRef<SessionEvent> client = getSession.replyTo;
          ActorRef<SessionCommand> ses =
              getContext()
                  .spawn(
                      SessionBehavior.create(getContext().getSelf(), getSession.screenName, client),
                      URLEncoder.encode(getSession.screenName, StandardCharsets.UTF_8.name()));
          // narrow to only expose PostMessage
          client.tell(new SessionGranted(ses.narrow()));
          sessions.add(ses);
          return this;
        }
  
        private Behavior<RoomCommand> onPublishSessionMessage(PublishSessionMessage pub) {
          NotifyClient notification =
              new NotifyClient((new MessagePosted(pub.screenName, pub.message)));
          sessions.forEach(s -> s.tell(notification));
          return this;
        }
      }
  
      static class SessionBehavior extends AbstractBehavior<ChatRoom.SessionCommand> {
        private final ActorRef<RoomCommand> room;
        private final String screenName;
        private final ActorRef<SessionEvent> client;
  
        public static Behavior<ChatRoom.SessionCommand> create(
            ActorRef<RoomCommand> room, String screenName, ActorRef<SessionEvent> client) {
          return Behaviors.setup(context -> new SessionBehavior(context, room, screenName, client));
        }
  
        private SessionBehavior(
            ActorContext<ChatRoom.SessionCommand> context,
            ActorRef<RoomCommand> room,
            String screenName,
            ActorRef<SessionEvent> client) {
          super(context);
          this.room = room;
          this.screenName = screenName;
          this.client = client;
        }
  
        @Override
        public Receive<SessionCommand> createReceive() {
          return newReceiveBuilder()
              .onMessage(PostMessage.class, this::onPostMessage)
              .onMessage(NotifyClient.class, this::onNotifyClient)
              .build();
        }
  
        private Behavior<SessionCommand> onPostMessage(PostMessage post) {
          // from client, publish to others via the room
          room.tell(new PublishSessionMessage(screenName, post.message));
          return Behaviors.same();
        }
  
        private Behavior<SessionCommand> onNotifyClient(NotifyClient notification) {
          // published from the room
          client.tell(notification.message);
          return Behaviors.same();
        }
      }
    }
    // #chatroom-behavior
  
    // #chatroom-gabbler
    public class Gabbler extends AbstractBehavior<ChatRoom.SessionEvent> {
      public static Behavior<ChatRoom.SessionEvent> create() {
        return Behaviors.setup(Gabbler::new);
      }
  
      private Gabbler(ActorContext<ChatRoom.SessionEvent> context) {
        super(context);
      }
  
      @Override
      public Receive<ChatRoom.SessionEvent> createReceive() {
        ReceiveBuilder<ChatRoom.SessionEvent> builder = newReceiveBuilder();
        return builder
            .onMessage(ChatRoom.SessionDenied.class, this::onSessionDenied)
            .onMessage(ChatRoom.SessionGranted.class, this::onSessionGranted)
            .onMessage(ChatRoom.MessagePosted.class, this::onMessagePosted)
            .build();
      }
  
      private Behavior<ChatRoom.SessionEvent> onSessionDenied(ChatRoom.SessionDenied message) {
        getContext().getLog().info("cannot start chat room session: {}", message.reason);
        return Behaviors.stopped();
      }
  
      private Behavior<ChatRoom.SessionEvent> onSessionGranted(ChatRoom.SessionGranted message) {
        message.handle.tell(new ChatRoom.PostMessage("Hello World!"));
        return Behaviors.same();
      }
  
      private Behavior<ChatRoom.SessionEvent> onMessagePosted(ChatRoom.MessagePosted message) {
        getContext()
            .getLog()
            .info("message has been posted by '{}': {}", message.screenName, message.message);
        return Behaviors.stopped();
      }
    }
    // #chatroom-gabbler
  
    // #chatroom-main
    public class Main {
      public static Behavior<Void> create() {
        return Behaviors.setup(
            context -> {
              ActorRef<ChatRoom.RoomCommand> chatRoom = context.spawn(ChatRoom.create(), "chatRoom");
              ActorRef<ChatRoom.SessionEvent> gabbler = context.spawn(Gabbler.create(), "gabbler");
              context.watch(gabbler);
              chatRoom.tell(new ChatRoom.GetSession("ol’ Gabbler", gabbler));
  
              return Behaviors.receive(Void.class)
                  .onSignal(Terminated.class, sig -> Behaviors.stopped())
                  .build();
            });
      }
  
      public static void main(String[] args) {
        ActorSystem.create(Main.create(), "ChatRoomDemo");
      }
    }
    // #chatroom-main
  
  }
  