Reactions is a main interface for building the response that should be sent back to the user. It also contains functions for dialogue state managing. That is why this abstraction has been named Reactions - it provides a ways to react somehow on the request from the user.

How to use

Each channel in JAICF creates its own channel-related Reactions implementation and provides it through the ActionContext to the action block of the scenario. Once the state is activated, JAICF executes its action block in context of this object, thus reactions interface becomes available for response building and dialogue state managing. Here is a simple example:

        state("fallback", noContext = true) {
            activators {

            action {
                reactions.say("I have nothing to say yet...")
                reactions.actions?.run {
                    say("Bye bye!")

Here you can see how reactions is used. Once a “fallback” state is activated, JAICF executes its action block. Reactions instance contains say method to send a raw text in the response to the user.

Channel that received a request and created this Reactions is responsive for this function invocation handling.

Response building methods

Each Reactions instance contains functions that help to build a response(s).


say method just appends a raw text reply to the response. There is also sayRandom variation of this method that picks a random text to append to response.


image method appends an image URL to the response.

Please note that not every channel supports this type of reply.


buttons method appends buttons array to the response. Can also activate states, for example:

reactions.buttons("How are you?" to "/HowAreYou", "Bye" to "/GoodBye")

And when user clicks the button How are you? state /HowAreYou will be activated.

Please note that not every channel supports this type of reply.

Channel-related reactions

You can also notice how channel-related reactions can be used.

In the example above there is a null-safe invocation of reactions.actions? that works only in case the request was received by Google Actions channel. In this case a channel-related reactions become available - like Actions-related endConversation function that finishes the Actions execution on a Google Assistant’s side.

To learn what channel-related functions are available, please look into a corresponding channel’s Reactions implementation. For example there are ActionsReactions for Google Actions, AlexaReactions for Alexa and etc.

Also it is important to know that you can extend any channel-related Reactions if it doesn’t contain methods you need. Because each Reactions holds a native response builder - thus you can use it directly.

Dialogue state managing

Reactions also can be used to jump through the states in dialogue scenario.

        state("setup") {
            action {
                val game = GameController(context)
                if (game.gamers == null) {
                    reactions.say("Okay! Let's start a new game!")
                    reactions.go("/setup/gamers", "next")
                } else {

            state("next") {
                action {
                    val game = GameController(context)
                    game.gamers = game.gamers ?: context.result as Int

                        say("${game.gamers} gamers! Cool! Now you have to choose a color for each of you!")
                        go("/setup/colors", "../complete")

            state("complete") {
                action {

Here you can see how reactions can be used to programmatically change the current state of the dialogue. Below you will find corresponding methods description.


go is one of the most used state managing method. It accepts the path (absolute or relative) to the next state to activate. JAICF activates this state immediately meaning that it invokes state’s action block and changes the current state to this one.

Also this method accepts an optional callback state. This state will be activated by JAICF once some inner dialogue action invokes goBack or changeStateBack method. It is a way to receive some result from the invocable state. It described in details below.


changeState method is similar to go but JAICF doesn’t invoke action block of the state in this case.


goBack method accepts an optional arbitrary value and activates a state that has been previously provided as a callback via go or changeState. The passed value can be obtained in the callback state via context.result:

In the example above you can see how it is used in “next” state that is passed previously as a callback state via reactions.go("/setup/gamers", "next").


changeStateBack method is similar to goBack but JAICF doesn’t invoke action block of the callback state in this case.