websockets4j Is a simple implementation of the WebSockets protocol. Currently supports the plain text version of Drafts 75 and 76 of the protocol. TLS support will be added in future releases.

Demo Application Video

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Maven Repository

Add to your pom.xml the following repository:

<repository> <id>com.juancavallotti</id> <name>websockets4j</name> <url>http://juancavallotti.com/maven2</url> <layout>default</layout> </repository>

Usage

This framework is very simple to use, here is an example of how it can be used in a servlets 3 container such as tomcat 7 or glassfish 3:

First, we extend the WebSocketServer so it can be Named and Singleton for CDI:

``` import com.juancavallotti.websockets4j.WebSocketServer; import javax.inject.Named; import javax.inject.Singleton;

@Named @Singleton public final class Server extends WebSocketServer {

} ```

Then we add a servlet ContextListener that starts the server when the application is deployed and stops it when the application is undeployed.

```

@WebListener public class WebappListener implements Serializable, ServletContextListener {

@Inject
private Server server;

private static final Logger log = Logger.getLogger(WebappListener.class.getName());

@Override
public void contextInitialized(ServletContextEvent sce) {
    if (!server.isStarted()) {
       server.start();
       server.registerListener("/context",<i>some class implementing {@link WebScoketListner}</i>);
       log.log(Level.INFO, "Started WebSocketServer");
   }
}

@Override
public void contextDestroyed(ServletContextEvent sce) {
        server.stop();
        log.log(Level.INFO, "Stopped WebSocketServer");
}

}

```

And the Javascript code in order to access the service:

```

var socket = new WebSocket("ws://some.host:10123/resource");

```

We can setup event listeners for the socket in javascript:

socket.onopen = function() { alert("Opened!") }; socket.onmessage = function (e) { alert("Message: "+e.data); }; socket.onclose = function() { alert("Closed!") }; socket.onerror = function() { alert("Error!") };

Port and backlog can be configured setting system properties. Please see javadoc API for further documentation.