WebSockets provide a standardized way for web browsers and servers to establish two-way communications channels over a single TCP connection. They allow for more efficient real-time messaging compared to older techniques like polling and long-polling. The WebSocket API defines client-side and server-side interfaces that allow for full-duplex communications that some popular Java application servers and web servers support natively. Common use cases that benefit from WebSockets include chat applications, online games, and real-time updating of social streams.

1. WEB SOCKETS
CURRENT STATE
FOR JAVA DEVELOPERS

2. Web SOCKETS
CURRENT STATE
FOR JAVA DEVELOPERS
PRESENTED
BY
VIKTOR
GAMOV

3. WEB SOCKETS
AGENDA
BIT OF MEET WEBSOCKETS Q&A
HISTORY THE WEBSOCKETS IN ACTION SESSION
?

4. OPTIONS FOR “REALTIME” WEB
“LEGACY” WEB
POLLING LONG-POLLING STEAMING
Browser sends HTTP requests at Browser sends a request to the
regular intervals and server and the server keeps the Browser sends a complete
immediately receives a request open for a set period request, but the server sends
response. However, real- time of time. If a notification is and maintains an open
data is often not that received within that period, a response that is continuously
predictable, making response containing the updated and kept open
unnecessary requests message is sent to the client. If indefinitely (or for a set period
inevitable and as a result, a notification is not received of time)
many connections are opened within the set time period, the
and closed needlessly in low- server sends a response to
message-rate situations terminate the open request.

5. WHAT IS WEBSOCKET
“Reducing kilobytes of data to 2 bytes... and reducing latency from 150ms to 50
ms is far more than marginal. In fact, these two factors alone are enough to make
WebSocket seriously interesting...”
www.ietf.org/mail-archive/web/hybi/current/msg00784.html

6. WHAT IS WEBSOCKETS?
WEB SOCKET
STANDARD PROTOCOL CLIENT-SIDE API SERVER-SIDE API
Websocket is a HTML5 specification True real-time server
standardized technology introduces WebSocket updates. Expected large
(described in RFC6455) client side object. No penetration in Java
to support low-overhead plugin required. world with upcoming
bidirectional traffic from JavaEE 7 spec and
your Web browser. JSR-356

7. WEBSOCKET HANDSHAKE
To Start full-duplex communication client should send
UPGRADE request
1 2 3 4
SEND RECEIVE CHANGE LISTEN
UPGRADE UPGRADE READYSTATE MESSAGE
REQUEST RESPONSE TO OPEN EVENT

8. DEMO
HANDSHAKE
DEMO

10. WEBSOCKET INTERFACE
[Constructor(DOMString
url,
optional
(DOMString
or
DOMString[])
protocols)]
interface
WebSocket
:
EventTarget
{
readonly
attribute
DOMString
url;
//
ready
state
const
unsigned
short
CONNECTING
=
0;
const
unsigned
short
OPEN
=
1;
const
unsigned
short
CLOSING
=
2;
const
unsigned
short
CLOSED
=
3;
readonly
attribute
unsigned
short
readyState;
readonly
attribute
unsigned
long
bufferedAmount;
//
networking
[TreatNonCallableAsNull]
attribute
Function?
onopen;
[TreatNonCallableAsNull]
attribute
Function?
onerror;
[TreatNonCallableAsNull]
attribute
Function?
onclose;
readonly
attribute
DOMString
extensions;
readonly
attribute
DOMString
protocol;
void
close([Clamp]
optional
unsigned
short
code,
optional
DOMString
reason);
//
messaging
[TreatNonCallableAsNull]
attribute
Function?
onmessage;
attribute
DOMString
binaryType;
void
send(DOMString
data);
void
send(ArrayBufferView
data);
void
send(Blob
data);
};

11. CLIENT-SIDE WEBSOCKET API
var
ws;
if
(window.WebSocket)
{
output("WebSocket
supported
in
your
browser");
ws
=
new
WebSocket("ws://www.websockets.org");
//
Set
event
handlers.
ws.onopen
=
function
()
{
output("onopen");
};
ws.onmessage
=
function
(e)
{
//
e.data
contains
received
string.
output("echo
from
server
:
"
+
e.data);
};
ws.onclose
=
function
()
{
output("onclose");
};
ws.onerror
=
function
()
{
output("onerror");
};
}
else
{output("WebSocket
not
supported
in
your
browser");}

12. JAVA EE 7 SERVER-SIDE API
package
org.javaee.glassfishwebsocket;
import
org.glassfish.websocket.api.annotations.WebSocket;
import
org.glassfish.websocket.api.annotations.WebSocketMessage;
@WebSocket(path
=
"/echo")
public
class
EchoBean
{
@WebSocketMessage
public
String
echo(String
message)
{
System.out.println("#####################
Message
received");
return
message
+
"
(from
your
server)";
}
}

13. TOMCAT 7.0.29 SERVER-SIDE API
SHOW
THE
CODE
Not enough room for code in this slide ;-)

14. PROGRAMMING WEBSOCKETS
Client-side frameworks
✦jquery.socket.js
✦https://github.com/flowersinthesand/jquery-socket/wiki
✦atmosphere.js
✦https://github.com/Atmosphere/atmosphere/wiki/jQuery.atmosphere.js-API
✦socket.io

15. WEBSOCKET SUPPORT
JAVA-based Web servers with native support.
The WebServer has API for WebSocket
✦Netty 3.3.x
✦Jetty 7.x, 8.x
✦Glassfish 3.1.2
✦Tomcat 7.0.27

16. WHAT SHOULD WE DO?
WE CAN DO IT!

17. WHAT IS ATMOSPHERE
Atmosphere
https://github.com/Atmosphere/atmosphere/
✦portable framework for
✦long-polling
✦Streaming
✦Server-Send Events
✦WebSockets
✦can auto select best transport
✦abstracting from actual underlying container
mechanism

18. THINKING ABOUT USE CASES
?

19. USE CASE
OUR CLIENTS
WebSockets really shine with following applications:
✦Live trading/sports ticker
✦Controlling medical equipment over the web
✦Chat applications
✦Multiplayer online games
✦Realtime updating social streams

20. BUNCH OF USEFUL LINKS
✦http://www.w3.org/TR/websockets/ MUST!
✦http://tools.ietf.org/html/rfc6455 MUST!
✦http://tomcat.apache.org/tomcat-7.0-doc/web-socket-howto.html
✦http://websocket-sdk.java.net/Introduction.html
✦https://github.com/Atmosphere/atmosphere/wiki/Supported-
WebServers-and-Browsers
✦http://autobahn.ws/testsuite

21. Q AND A
Q&A
Put your questions

22. CONTACT US
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INFO@FARATASYSTEMS.COM

23. FIND ME
TWITTER GITHUB
WWW.TWITTER.COM/GAMUSSA WWW.GITHUB.COM/GAMUSSA

24. THANK YOU
THANK YOU
FOR YOUR ATTENTION
HTTP://WWW.FARATASYSTEMS.COM