Events

Twitch4J uses Events4J to dispatch events and handle them, you can also build your own event handler to handle them however you like. You can use those events to build chat bots or similar tools.

Publish Event

Publish a event that should be processed somewhere:

• The event object needs to implement the IEvent interface.
• The event will be passed to all registered handlers.

Java

eventManager.publish(object);

Kotlin

eventManager.publish(`object`)

Groovy

eventManager.publish(object)

Handle / Process Events

Twitch4J uses the SimpleHandler by default which works on all platforms.

Handlers:

• SimpleHandler
• ReactorHandler
• SpringHandler

You can register listeners directly on the eventManager, the call is forwarded and registered on the current defaultEventHandler set in the eventManager instance.

Switch the default event handler

If you want all your events to be processed by a specific eventHandler, then check out the following pages on all available eventHandlers:

• SimpleEventHandler (Default)
• ReactorEventHandler

Register your event listeners in a generic way

Only the consumers registered with eventManager.onEvent will use the defaultEventHandler.

Java

// register handler
IDisposable handlerReg = twitchClient.getEventManager().onEvent(ChannelMessageEvent.class, event -> {
	System.out.println "[" + event.getChannel().getName() + "]["+event.getPermissions().toString()+"] " + event.getUser().getName() + ": " + event.getMessage());
});

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose();

Kotlin

// register handler
val handlerReg = twitchClient.eventManager.onEvent(ChannelMessageEvent::class.java) { event ->
	println("[${event.channel.name}][${event.permissions}] ${event.user.name}: ${event.message}")
}

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose()

Groovy

// register handler
def handlerReg = twitchClient.eventManager.onEvent(ChannelMessageEvent) { event ->
	System.out.println "[${event.channel.name}][${event.permissions}] ${event.user.name}: ${event.message}"
}

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose()

This is the recommended method to register listeners, as you can switch between the different EventHandlers by chaning a single line of code.

Simple Handler

The default event handler can register handlers with annotations or provide lambdas as consumers.

Lambda / Consumer Example

Java

// register handler
IDisposable handlerReg = twitchClient.getEventManager().getEventHandler(SimpleEventHandler.class).onEvent(ChannelMessageEvent.class, event -> {
	System.out.println("[" + event.getChannel().getName() + "]["+event.getPermissions().toString()+"] " + event.getUser().getName() + ": " + event.getMessage());
});

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose();

Kotlin

// register handler
val handlerReg = twitchClient.eventManager.getEventHandler(SimpleEventHandler::class.java).onEvent(ChannelMessageEvent::class.java) { event -> 
	println("[${event.channel.name}][${event.permissions}] ${event.user.name}: ${event.message}")
}

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose()

Groovy

// register handler
def handlerReg = twitchClient.eventManager.getEventHandler(SimpleEventHandler).onEvent ChannelMessageEvent, { event -> 
	System.out.println "[${event.channel.name}][${event.permissions}] ${event.user.name}: ${event.message} "
}

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose()

Annotation Example

Java

public class MyEventHandler {

    // the type of the 1st argument is relevant, you can pick any method name you want
    @EventSubscriber
    public void printChannelMessage(ChannelMessageEvent event) {
        System.out.println("[" + event.getChannel().getName() + "]["+event.getPermissions().toString()+"] " + event.getUser().getName() + ": " + event.getMessage());
    }

}

// register your handler class
MyEventHandler myEventHandler = new MyEventHandler();
eventManager.getEventHandler(SimpleEventHandler.class).registerListener(myEventHandler);

Kotlin

class MyEventHandler {

    // the type of the 1st argument is relevant, you can pick any method name you want
    @EventSubscriber
    fun printChannelMessage(ChannelMessageEvent event) {
        println("[${event.channel.name}][${event.permissions}] ${event.user.name}: ${event.message}")
    }

}

// register your handler class
val myEventHandler = MyEventHandler();
eventManager.getEventHandler(SimpleEventHandler::class.java).registerListener(myEventHandler);

Groovy

class MyEventHandler {

    // the type of the 1st argument is relevant, you can pick any method name you want
    @EventSubscriber
    def printChannelMessage(ChannelMessageEvent event) {
        System.out.println "[${event.channel.name}][${event.permissions}] ${event.user.name}: ${event.message}"
    }

}

// register your handler class
def myEventHandler = new MyEventHandler();
eventManager.getEventHandler(SimpleEventHandler).registerListener(myEventHandler);

Cheat Sheet

Key	Value
Handler Execution	sync
Android	compatible

Reactor Handler

If desired you can also use the ReactorHandler to use reactive streams to process events (keep in mind that this will not work with android). To enable reactor add the ReactorHandler dependency, it will be discovered and registered automatically.

Gradle

build.gradle

dependencies {
    implementation 'com.github.philippheuer.events4j:events4j-handler-reactor:0.12.2'
}

Gradle - Kotlin DSL

build.gradle.kts

dependencies {
    implementation("com.github.philippheuer.events4j:events4j-handler-reactor:0.12.2")
}

Maven

pom.xml

<dependency>
    <groupId>com.github.philippheuer.events4j</groupId>
    <artifactId>events4j-handler-reactor</artifactId>
    <version>0.12.2</version>
</dependency>

Java

// register handler
Disposable handlerReg = twitchClient.getEventManager().getEventHandler(ReactorEventHandler.class).onEvent(ChannelMessageEvent.class, event -> {
	System.out.println("[" + event.getChannel().getName() + "]["+event.getPermissions().toString()+"] " + event.getUser().getName() + ": " + event.getMessage());
});

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose();

Kotlin

// register handler
val handlerReg = twitchClient.eventManager.getEventHandler(ReactorEventHandler::class.java).onEvent(ChannelMessageEvent::class.java) { event ->
	println("[${event.channel.name}]${event.permissions}] ${event.user.name}: ${event.message}")
}

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose();

Groovy

// register handler
def handlerReg = twitchClient.eventManager.getEventHandler(ReactorEventHandler).onEvent ChannelMessageEvent, { event ->
	System.out.println "[${event.channel.name}]${event.permissions}] ${event.user.name}: ${event.message}"
}

// cancel handler (don't call the method for new events of the required type anymore)
handlerReg.dispose();

Cheat Sheet

Key	Value
Handler Execution	async
Android	incompatible

Spring Handler

If desired you can also use the SpringHandler to handle all events as Spring Application Events. To enable reactor add the SpringHandler dependency, it will be discovered and registered automatically.

Gradle

build.gradle

dependencies {
    implementation 'com.github.philippheuer.events4j:events4j-handler-spring:0.12.2'
}

Gradle - Kotlin DSL

build.gradle.kts

dependencies {
    implementation("com.github.philippheuer.events4j:events4j-handler-spring:0.12.2")
}

Maven

pom.xml

<dependency>
    <groupId>com.github.philippheuer.events4j</groupId>
    <artifactId>events4j-handler-spring</artifactId>
    <version>0.12.2</version>
</dependency>

Event Catalog

This will become a list of all available events.

Channel:

• ChannelMessageEvent
• ChannelChangeGameEvent
• ChannelChangeTitleEvent
• ChannelGoLiveEvent
• ChannelGoOfflineEvent

User:

• PrivateMessageEvent

Generic:

• IRCMessageEvent

And many more, this is a very incomplete list

Please visit our javadocs to find a more complete list of events:

• Chat
• Client Helper
• EventSub
• PubSub