Server-Sent Events
Server-Sent Events (SSE) is a standard and part of HTML 5; it allows for one-way communication from the server to the client. So, a client can make one request and the server can keep sending multiple responses on the same connection. The client opens the connection with a server by passing the Accept header as text/event-stream. This connection is a long-running one between the client and server. The server can then publish events over the HTTP protocol. This allows for a better solution for pushing updates to clients than clients having to resort to inefficient means such as polling. JAXRS 2.1 has made API enhancements to support SSE. On the server-side, we can define a resource that produces text/event-stream, which clients can register with to receive events. Let's look at an example, where we combine CDI and JAXRS to push task updates to the interested clients. First, we need to understand the tools at our disposal to create this magic.
In order to listen to client...
