Java Websocket containers: the possibilities

The Java Websocket API (JSR 356) specification supports different containers

Good old Java EE 7 app servers – since Websocket API is integrated directly into the Java EE 7 Platform
Servlet 3.1 containers
Standalone containers – for runtimes which are not servlet complaint

Hello Tyrus !

Tyrus is the reference implementation for Java Websocket API

What’s important to understand is that it’s the implementation of the Websocket specification i.e. it provides both Server and Client side support for building Websocket applications using the standard JSR 356 APIs
It’s not an out-of-the-box container i.e. does not have a runtime as such

So, how does Tyrus support the above mentioned runtimes ?

Here is how

Tyrus has a modular architecture i.e. it has different modules for server, client implementations, a SPI etc.
It has the concepts of containers (you can think of them as connectors) for specific runtime support (these build on the modular setup)

Tyrus containers

Servlet container a.k.a tyrus-container-servlet

Used to integrate with existing Servlet 3.1 containers
Leveraged to plug into the Web (Servlet) Container in Java EE 7 compliant app servers

Standalone container

You have two options

Grizzly Container (tyrus-container-grizzly module)

This is achieved with Grizzly (which provides the runtime)
Can be used for server or client (or both) modes as per your requirements

Here are the Maven dependencies

	…
	<dependencies>
	<dependency>
	<groupId>javax.websocket</groupId>
	<artifactId>javax.websocket-api</artifactId>
	<version>1.1</version>
	</dependency>
	<dependency>
	<groupId>org.glassfish.tyrus</groupId>
	<artifactId>tyrus-server</artifactId>
	<version>1.12</version>
	</dependency>
	<dependency>
	<groupId>org.glassfish.tyrus</groupId>
	<artifactId>tyrus-container-grizzly-server</artifactId>
	<version>1.12</version>
	</dependency>
	</dependencies>
	…

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tyrus-grizzly-container-maven-deps.txt

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Here is the Websocket (annotated) endpoint

	//imports ommitted

	@ServerEndpoint("/testwsep")
	public class MyWsendpoint {

	static Set<Session> clients = new HashSet<Session>();

	@OnOpen
	public void open(Session s) {
	clients.add(s);
	}

	@OnMessage
	public void msg(String m) {
	for (Session client : clients) {
	try {
	client.getBasicRemote().sendText("Catch this! "+ m);
	} catch (IOException ex) {
	Logger.getLogger(MyWsendpoint.class.getName()).log(Level.SEVERE, null, ex);
	}
	}
	}
	//.. other callback methods ommitted – @onClose, @onError
	}

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MyWsendpoint.java

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Here is how to start it (embedded)

	public class TyrusGrizzlyWebsocketRunner {

	public static void main(String[] args) throws DeploymentException, IOException, InterruptedException {
	Server server = new Server("localhost", 8080, "", null, MyWsendpoint.class);
	server.start();
	System.out.print("—- Server Started —–");
	new CountDownLatch(1).await();
	}
	}

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TyrusGrizzlyWebsocketRunner.java

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Pure JDK container (tyrus-container-jdk-client module)

Client only mode
Vanilla JDK i.e. no additional dependencies
Leverages JDK 1.7 non-blocking I/O (Asynchronous Channel)

Maven dependencies

	<dependencies>
	<dependency>
	<groupId>javax.websocket</groupId>
	<artifactId>javax.websocket-api</artifactId>
	<version>1.1</version>
	</dependency>
	<dependency>
	<groupId>org.glassfish.tyrus</groupId>
	<artifactId>tyrus-client</artifactId>
	<version>1.12</version>
	</dependency>
	<dependency>
	<groupId>org.glassfish.tyrus</groupId>
	<artifactId>tyrus-container-jdk-client</artifactId>
	<version>1.12</version>
	</dependency>
	</dependencies>

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tyrus-cliet-jdk-container-maven-deps.txt

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The (annotated) client endpoint

	@ClientEndpoint
	public class WebsocketAnotatedClient {

	@OnOpen
	public void onopen(){
	System.out.println("connected to server…. ");
	}

	@OnMessage
	public void onmsg(String msg){
	System.out.println("recieved from server…. "+ msg);
	}
	}

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WebsocketAnotatedClient.java

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Client code to connect to Websocket endpoint (outlined above)

	public class WebsocketClientOnVaniallJDKRunner {

	public static void main(String[] args) throws DeploymentException, IOException, InterruptedException {
	WebSocketContainer cc = ContainerProvider.getWebSocketContainer();
	Session connectToServer = cc.connectToServer(WebsocketAnotatedClient.class, URI.create("ws://localhost:8080/testwsep"));

	new CountDownLatch(1).await();
	}

	}

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WebsocketClientOnVaniallJDKRunner.java

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Additional reading

Cheers!