Bot Developer Kit for Java

BDK 3.0 has been released! The BDK 2.0 will stop being supported in August 2024. Please consider migrating to keep up with the latest features!

Overview

The BDK for Java is Symphony Messaging's preferred tooling for Java developers to build bots. It is a library of tools and API bindings that provides simplified configuration and authentication, intuitive message and room management, customizable message templating and an activities API that makes it easy to build bot workflows.

• The BDK for Java Github repo can be found here: @finos/symphony-bdk-java

• The BDK for Java Certification course can be found here: learn.symphony.com/bundles/java-bot-developer

Getting Started

Getting Started with BDK

Authentication

Once you have your bot and Symphony Messaging environment properly configured, the generated code provides an out-of-the-box implementation for authenticating your bot:

BotApplication.java

SymphonyBdk bdk = new SymphonyBdk(loadFromClasspath("/config.yaml"));

By instantiating a new SymphonyBdk instance with your config.yaml file, the BDK loads in your config and authenticates your bot. Once authenticated, your bot is ready to leverage the REST APIs in order to create rich automations and workflows on Symphony Messaging.

Note: You must have a corresponding service or bot account setup on your Symphony Messaging instance before authenticating. For more information navigate to the Creating a Bot User guide.

OBO Authentication

BDK for Java also supports the OBO (On-Behalf-Of) pattern of authentication, allowing an authenticated bot + extension application to perform operations on behalf of a given user. The BDK's implementation makes it easy to perform the following operations on behalf of a given user:

• List the streams of a given user

• Initiate connection requests to and determine connection status with other users

• Get the presence state of other connected users

• Initiate IMs with other users

• Send messages and attachments

• Set the context user's own presence

Please follow our 'Getting Started with OBO' guide using the link here. The guide will cover all of the prerequisites needed for OBO and how to enable & upload the OBO extension application, the required permissions and how to ensure the OBO authentication process will work successfully.

To leverage an OBO based workflow, simply instantiate an OBO Session in your bot project. The BDK allows you to instantiate your OBO session from a username or user ID. Once authenticated bots can perform any of the OBO workflows listed above:

 // setup SymphonyBdk facade object
 final SymphonyBdk bdk = new SymphonyBdk(loadFromSymphonyDir("config.yaml"));

 //authenticate on-behalf-of a given user
 final AuthSession oboSessionUsername = bdk.obo("user.name");
 final AuthSession oboSessionUserId = bdk.obo(123456789L);

 // list streams OBO user "user.name"
 bdk.streams().listStreams(oboSessionUsername, new StreamFilter());

Managing Multiple Bots

BDK for Java makes it easy to manage multiple bot instances within a single project. As long as you have unique configuration files that correspond to different service accounts, you can manage multiple bot instances from a centralized source. To do so, simply instantiate multiple bot instances of the SymphonyBDK class within your bot project:

// Bot #1
final SymphonyBdk bot1 = new SymphonyBdk(loadFromClasspath("/config_1.yaml"));

//Bot #2
final SymphonyBdk bot2 = new SymphonyBdk(loadFromClasspath("/config_2.yaml"));

Datafeed Management

The BDK also provides a DatafeedService interface that makes it easier than ever for bots to manage real-time messages and events. The DatafeedService interface provides the following methods for your bot to use:

Method	Descriptions
start()	Start the bot's datafeed
stop()	Stop the bot's datafeed
subscribe(RealTimeEventListener)	Subscribe a custom event listener class. Inside this class is where the bulk of your business logic goes.
unsubscribe(RealTimeEventListener)	Unsubscribe from a custom event listener class.

For bots to listen to incoming events and messages, bots must subscribe to a custom RealTimeEventListener. This RealTimeEventListener class must implement eventType methods (e.g. onMessageSent()) along with custom business logic inside.

When a user sends a bot a message, the bot will pick up the event from the datafeed and check to see if an implemented eventType method matches the eventType (MESSAGESENT) of the inbound event. If there is a corresponding eventType method registered, the bot will execute the business logic inside of this eventType method. Otherwise the bot will not perform an action and will continue to listen for inbound events from the datafeed. An example implementation is provided out of the box by the BDK:

BotApplication.java

 // subscribe to "onMessageSent" real-time event
    bdk.datafeed().subscribe(new RealTimeEventListener() {

      @Override
      public void onMessageSent(V4Initiator initiator, V4MessageSent event) {
        // on a message sent, the bot replies with "Hello, {User Display Name}!"
        bdk.messages().send(event.getMessage().getStream(), "<messageML>Hello, " + initiator.getUser().getDisplayName() + "!</messageML>");
      }
    });

Below is a full list of methods provided by the RealTimeEventListener class and their corresponding eventTypes. Implement the following methods in order to listen for a given Symphony Messaging event:

Method	Event Type
onMessageSent()	MESSAGESENT
onInstantMessageCreated()	INSTANTMESSAGECREATED
onMessageSuppressed()	MESSAGESUPPRESSED
onRoomCreated()	ROOMCREATED
onRoomUpdated()	ROOMUPDATED
onRoomDeactivated()	ROOMDEACTIVATED
onRoomReactivated()	ROOMACTIVATED
onUserRequestedToJoinRoom()	USERREQUESTEDTOJOINROOM
onUserJoinedRoom()	USERJOINEDROOM
onUserLeftRoom()	USERLEFTROOM
onRoomMemberPromotedToOwner()	ROOMMEMBERPROMOTEDTOOWNER
onRoomMemberDemotedFromOwner()	ROOMMEMBERDEMOTEDFROMOWNER
onConnectionRequested()	CONNECTIONREQUESTED
onConnectionAccepted()	CONNECTIONACCEPTED
onSymphonyElementsAction()	SYMPHONYELEMENTSACTION
onSharedPost()	SHAREDPOST

For more information on the Symphony Messaging datafeed continue here:

Datafeed

Orchestrating Workflows with BDK for Java

A Symphony Messaging workflow can be thought of as a sequence of operations or a repeatable pattern of activities that are organized together in order to transform data, provide a service, or process information. Each of these operations or activities may be completed by a single user, shared between a bot and a user, or shared between multiple actors including bots, users, and even third party systems.

By providing an intuitive Activities API, the BDK makes it simple to define a set of discrete operations or activities for different actors in your system to execute. Ultimately, these activities constitute the building blocks for a powerful Symphony Messaging workflow automation.

Once you have defined a discrete set of activities for different actors in your system to execute, the next step is to organize them together in an intelligent way. The BDK provides a powerful Workflow API (coming soon) that makes it easy to organize a sequence of activities together, and subsequently orchestrate a Symphony Messaging workflow.

Activities API

BDK for Java provides an Activities API, an interface that makes it easy to manage user-to-bot interactions or activities. Specifically, the Activities API provides easy access to message and room context, initiator metadata, and an intuitive way to interact with the datafeed, making it easy for bots to listen and reply to different Symphony Messaging events. The methods and logic provided by the Activities API allows for granular control over the entire user-to-bot interaction. This encapsulated logic is easily reused, forming the discrete building blocks of a Symphony Messaging workflow automation.

Registering Activities

In order to register activities for your bot instance, you must leverage the ActivityRegistry class:

public static void main(String[] args) throws Exception {
    // Create BDK entry point
    final SymphonyBdk bdk = new SymphonyBdk(loadFromSymphonyDir("config.yaml"));
    // Access to the registry for activities
    final ActivityRegistry registry = bdk.activities();
  }

There are two different types of activities supported by the BDK:

• Command Activity: an activity triggered when a message is sent in an IM or Chatroom.

• Form Activity: an activity triggered when a user replies to an Elements form message.

Command Activities

A command-based activity is triggered when a message is sent in an IM or Chatroom. Using the Activities API allows developers to register commands in the following formats:

• @bot/buy (Slash command with a bot @mention)

@bot /hello

bdk.activities().register(slash("/hello", true, context -> {
  String message = "Hello " + context.getInitiator().getUser().getDisplayName();
  bdk.messages().send(context.getStreamId(), message);
}));

• /buy 1000 $goog (Slash command without a bot @mention)

/buy 1000 $goog

bdk.activities().register(slash("/buy {quantity} {$ticker}", false, context -> {
  Arguments arguments = context.getArguments();
  String quantity = arguments.getString("quantity");
  String ticker = arguments.getAsString("ticker").substring(1);
  String message = "Buy " + quantity + " of <cash tag=\"" + ticker + "\" />";
  bdk.messages().send(context.getStreamId(), message);
}));

• Listen for the word hello (Not a Slash command - just listen for messages containing a specific word)

'hello'

bdk.activities().register(new CommandActivity<>() {
  protected ActivityMatcher<CommandContext> matcher() throws EventException {
    return c -> c.getTextContent().contains("hello");
  }
  
  protected void onActivity(CommandContext context) throws EventException {
    bdk.messages().send(context.getStreamId(), "Hello!");
  }
  
  protected ActivityInfo info() {
    return new ActivityInfo().name("Hello Command");
  }
});

Note: If you choose to create your own CommandActivity class, you must implement the matcher() and onActivity() methods provided by the AbstractActivity class. For more information on the implementation of the CommandActivity class, continue here.

Form Activities

The Activities API also makes it easy for Bots to listen for elements form submissions. Assume the following elements form has been posted into a room with the following attributes:

• form id = "hello-form"

• <text-field> name = "name"

• form contains an action button

<h2>Hello Form</h2>
<form id="hello-form">
  <text-field name="name" placeholder="Enter a name here..." />
  <button name="submit" type="action">Submit</button>
</form>

In order to register a form activity or listen for an incoming elements form submission, bots must register a class that extends the FormReplyActivity class:

bdk.activities().register(new FormReplyActivity<>() {
  protected ActivityMatcher<FormReplyContext> matcher() throws EventException {
    return c -> c.getFormId().equals("hello-form");
  }

  protected void onActivity(FormReplyContext context) throws EventException {
    final String message = "Hello, " + context.getFormValue("name");
    bdk.messages().send(context.getStreamId(), message);
  }

  protected ActivityInfo info() {
    return new ActivityInfo().name("Hello Form");
  }
});

Note: If you wish to create your own FormReplyActivity class, you must implement the methods matcher(), onActivity() and info() methods provided by the AbstractActivity class. For more information on the implementation for the FormReplyActivity class, continue here.

As shown above, the Activities API makes it simple to manage incoming commands, elements form submissions, and access message context making it easy to manage bot-user interactions and create custom workflows.

User, Message & Room Management

As shown above, the BDK makes it easy to create a datafeed and listen for events through the RealTimeEventListener class. In addition, this class makes it easy to access user, message, and room data in context. Each eventType method is implemented with instances of V4Initiator and V4MessageSent objects:

public void onMessageSent(V4Initiator initiator, V4MessageSent event)

Use the V4Initiator class methods to access the the user data in context:

Method	User Attribute
initiator.getUser().getUserId()	User ID
initiator.getUser().getFirstName()	First Name
initiator.getUser().getLastName()	Last Name
initiator.getUser().getDisplayName()	Display Name
initiator.getUser().getEmail()	Email
initiator.getUser().getUsername()	Username

Use the V4MessageSent class methods to access message data in context:

Method	Attribute
event.getMessage().getMessageId()	Message ID
event.getMessage().getTimestamp()	Message Timestamp
event.getMessage().getMessage()	Message Text
event.getMessage().getSharedMessage()	Shared Message
event.getMessage().getData()	Message Data
event.getMessage().getAttachments()	Message Attachments

Use the V4MessageSent class methods to access stream data in context:

Method	Attribute
event.getMessage().getStream().getStreamId()	Stream ID
event.getMessage().getStream().getStreamType()	Stream Type
event.getMessage().getStream().getRoomName()	Room Name
event.getMessage().getStream().getMembers()	Room Members
event.getMessage().getStream().getExternal()	External
event.getMessage().getStream().getCrossPod()	Cross Pod

Managing Context through Activities API

The Activities API also makes it easy to access relevant user, message, and stream data in context. CommandActivity classes have access to to this data through the CommandContext class. This class is instantiated with instances of V4Initiator and V4MessageSent objects. Bots are able access to the user, message, and stream data in context through the same methods shown above. Leverage these methods within the onActivity() method shown below:

@Override
protected void onActivity(CommandContext context) {
  log.info("Hello command triggered by user {}", context.getInitiator().getUser().getDisplayName()); // (2)
}

FormActivity classes have access to relevant user, form, and stream data through the FormReplyContext class. This class is instantiated with instances of the V4Initiator and V4SymphonyElementsAction class. The V4SymphonyElementsAction class provides the following methods to access form data in context:

Method	Attribute
context.getSourceEvent().getStream()	Elements Stream ID
context.getSourceEvent().getFormMessageId()	Elements Message ID
context.getSourceEvent().getFormId()	Elements Form ID
context.getSourceEvent().getFormValues()	Elements Form Values

@Override
  protected void onActivity(FormReplyContext context) {
    final String message = "You entered " + context.SourceEvnent().getFormValues() + ".";
    this.messageService.send(context.getSourceEvent().getStream(), "<messageML>" + message + "</messageML>");
  }

Message Templating

The BDK for Java also supports custom and built in message templating. The BDK is agnostic to what templating library developers choose, with built-in support for FreeMarker and Handlebars. In order to use message templating, you must leverage the TemplateEngine class provided by the BDK.

String message = bdk.messages().templates()
    .newTemplateFromString("Hello ${value}")
    .process(Map.of("value", "World"));
bdk.messages().send(context.getStreamId(), message);

If you wish to build your own custom message template, you must implement one of the newTemplate() methods provided by the TemplateEngine class:

• newTemplateFromFile()

• newTemplateFromClasspath()

• newTemplateFromString()

The following shows an implementation of the newTemplateFromClasspath() method:

String message = bdk.messages().templates()
    .newTemplateFromClasspath("hello.ftl")
    .process(Map.of("value", "World"));
bdk.messages().send(context.getStreamId(), message);

The corresponding FreeMarker template should be stored in the classpath root i.e. src/main/resources/hello.ftl

hello.ftl

Hello ${value}

Spring Boot Integration

The BDK for Java's Spring Boot integration provides native annotations, making it easy to configure your bot's datafeed listeners and register command activities. Start with a standard Spring Boot main class.

@SpringBootApplication
public class BotApplication {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

@Component

Now you can create a component for bot applications by annotating classes with the @Component annotation:

@Component
public class HelloCommand {
  @Autowired
  private MessageService messages;

  @EventListener
  public void onMessageSent(RealTimeEvent<? extends V4MessageSent> event) {
    messages.send(event.getSource().getMessage().getStream(), "Hello!");
  }
}

@EventListener

The Core Starter uses Spring Events to deliver Real Time Events.

You can subscribe to any Real Time Event from anywhere in your application by creating a handler method with two conditions:

• Be annotated with @EventListener
• Have a com.symphony.bdk.spring.events.RealTimeEvent<? extends T> parameter

@Slf4j
@Component
public class RealTimeEventsDemo {
  @EventListener
  public void onMessageSent(RealTimeEvent<? extends V4MessageSent> event) {
    log.info(event.toString());
  }

  @EventListener
  public void onUserJoined(RealTimeEvent<? extends V4UserJoinedRoom> event) {
    log.info(event.toString());
  }

  @EventListener
  public void onUserLeft(RealTimeEvent<? extends V4UserLeftRoom> event) {
    log.info(event.toString());
  }
}

@Slash

You can easily register a slash command using the @Slash annotation. Note that the CommandContext is mandatory to successfully register your command. If not defined, a warn message will appear in your application log:

@Component
public class SlashHello {

  @Slash("/hello")
  public void onHello(CommandContext commandContext) {
    log.info("On /hello command");
  }

  @Slash(value="/hello", mentionBot=false)
  public void onHelloNoMention(CommandContext commandContext) {
    log.info("On /hello command (bot has not been mentioned)");
  }
}

Activities

Any service or component class that extends FormReplyActivity or CommandActivity will be automatically registered within the ActivityRegistry

@Slf4j
@Component
public class GifFormActivity extends FormReplyActivity<FormReplyContext> {
  @Autowired
  private MessageService messageService;

  @Slash("/gif")
  public void displayGifForm(CommandContext context) throws TemplateException {
    this.messageService.send(context.getStreamId(), "/templates/gif.ftl", emptyMap());
  }
  
  public ActivityMatcher<FormReplyContext> matcher() {
    return context -> "gif-category-form".equals(context.getFormId())
        && "submit".equals(context.getFormValue("action"))
        && StringUtils.isNotEmpty(context.getFormValue("category"));
  }
  
  public void onActivity(FormReplyContext context) {
    log.info("Gif category is \"{}\"", context.getFormValue("category"));
  }

  protected ActivityInfo info() {
    return new ActivityInfo().type(ActivityType.FORM)
        .name("Gif Display category form command")
        .description("Form handler for the Gif Category form");
  }
}