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
WWW.FARATASYSTEMS.COM
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