scalableenterpriseapplicationswith jee7andbeyond

2013 © Trivadis

BASEL BERN LAUSANNE ZÜRICH DÜSSELDORF FRANKFURT A.M. FREIBURG I.BR. HAMBURG MÜNCHEN STUTTGART WIEN

JUG Münster Scalable enterprise

applications with JEE7

and beyond

Andy Moncsek

17. April 2013

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2013 © Trivadis


Andy Moncsek

Consultant for Application Devlopment (Zürich)

Trainer for JavaEE Assembly & Deployment

Contacts: [email protected]

Twitter: @AndyAHCP

mailto:[email protected]

2013 © Trivadis

AGENDA

1. Motivation

2. Server Sent Events

3. WebSocket (JSR-356)

4. SSE & WebSockets in Enterprise

Security

Loadbalancing / Failover

5. (short) JEE 7 project overview

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Motivation

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JEE 7

what’s new?

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Motivation

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state: function() { return state; }, always: function() { deferred.done(

arguments ).fail( arguments ); return this; }, then: function( /*

fnDone, fnFail, fnProgress */ ) { var fns = arguments; return

jQuery.Deferred(function( newDefer ) { jQuery.each( tuples,

function( i, tuple ) { var action = tuple[ 0 ], fn = jQuery.isFunction(

fns[ i ] ) && fns[ i ]; // deferred[ done | fail | progress ] for

forwarding actions to newDefer deferred[ tuple[1] ](function() { var

returned = fn && fn.apply( this, arguments ); if ( returned &&

jQuery.isFunction( returned.promise ) ) { returned.promise() .done(

newDefer.resolve ) .fail( newDefer.reject ) .progress(

newDefer.notify ); } else { newDefer[ action + "With" ]( this ===

promise ? newDefer.promise() : this, fn ? [ returned ] : arguments );

} }); }); fns = null; }).promise(); },

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Focus

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Java

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Server Sent Events

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Server Sent Events - Overview

• push from server to client

• SSE EventSource API part

of HTML5

• Part of Jersey 2 API’s (JAX-RS)

• JMS – Topic(Light)?

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SSE

DEMO

https://bitbucket.org/amoncsek/jeemax

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https://bitbucket.org/amoncsek/jeemax

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SSE

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TimerBean:

write(new Event(«custom»,data));

Handle:void onEvent(InboundEvent e)

@Path(«myEventStream»)

Subscibe once:new EventSource(http://.../myEventStream)

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SSE- ServerSide

• Subscribe an Event Stream

@GET

@Produces(SseFeature.SERVER_SENT_EVENTS)

public EventOutput getEventStream() {

return new EventOutput();

}

• Put Message to EventOutput

EventOutput.write(

new OutboundEvent("custom-message“, message))

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SSE– ClientSide (Jersey 2 API’s)

• Client API

Client client = ClientBuilder.newClient();

WebTarget webTarget = client.target(TARGET_URI);

• EventSource API

new EventSource(webTarget) {

public void onEvent(InboundEvent event) {…}

}

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SSE– Best Practice

• Client: EventSource.close() also closes the Server: EventOutput!

• Use SseBroadcaster to broadcast messages to EventOutput

• Register: SseBroadcaster.add(EventOutput)

• Broadcast: SseBroadcaster.broadcast(OutboundEvent)

• Use Server: OutboundEvent.name(«myMessage») to filter

messages (like JMS message-property/selector)

• Client: InboundEvent.getName().equals(«myMessage»)

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SSE

Any questions?

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WebSocket (JSR-356)

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WebSocket - Overview

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• Full duplex communication in either

direction

• Java API for Server- and Client-Side

(JEE7)

• Programmatic and annotation-based

endpoints

• Support for Encoder/Decoder to map

message to Java objects

• Support for @PathParam

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WebSocket(JSR 356) - Overview

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• Part of Glassfish 4

• Tyrus project:

• reference implementation for JSR 356 WebSocket API for Java

• http://java.net/projects/tyrus

http://java.net/projects/tyrus

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WebSocket

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@ServerEndpoint("/bookings") @ClientEndpoint

Session Session

messages

Connect

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WebSocket – ServerEndpoint (by annotation)

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• Creating Server Endpoints with annotation

@ServerEndpoint("/bookings")

public class BookingEndpoint {

@OnOpen

public void init(Session s) {}

@OnClose

…

@OnError

…

@OnMessage

public void handleMessage(Message m, Session s) {}

}

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WebSocket – ServerEndpoint (programmatic)

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• Creating Server Endpoints programmatic

public class BookingEndpoint extends Endpoint {

@Override

public void onOpen(Session s, EndpointConfig ec) {

s.addMessageHandler(new MessageHandler() {

@Override

public void onMessage(String text) {…}

});

}

}

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WebSocket - ServerEndpoint

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• Configuring a programmatic Endpoint (WebSocket runtime scans the

WAR)

public class WSAppConfig implements ServerApplicationConfig

{

public Set<ServerEndpointConfig> getEndpointConfigs(Set

set) {

add(ServerEndpointConfig.Builder

.create(BookingEndpoint.class, "/bookings")

.build());

}

}

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WebSocket - ClientEndpoint

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• Creating Client Endpoints with annotation

@ClientEndpoint

public class Booking {

@OnOpen

…

@OnClose

…

@OnError

…

@OnMessage

…

}

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• Creating programmatic Client Endpoint

public class Booking extends Endpoint {

@Override

public void onOpen(Session s, EndpointConfig c) {

s.addMessageHandler(…);

}

}

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• Configure a Client Endpoint

ClientManager client = ClientManager.createClient();

ClientEndpointConfig config =

ClientEndpointConfig.Builder.create();

client.connectToServer(new Booking(),config

URI.create(“ws://host/bookings“));

Or

client.connectToServer(Booking.class,config

URI.create(“ws://host/bookings“));

2013 © Trivadis

WebSocket Encoder/Decoder

• Native Message-format is:

• Text

• Binary

• Pong (check connection)

• Encoders:

• Encode message from Java Object to Binary / Text

• Decoders

• Decode message from Binary / Text to Java Object

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WebSocket Encoder

public class MEnc implements Encoder.Binary<Message> {

@Override

public ByteBuffer encode(Message m) throws EncodeException {

return ByteBuffer.wrap(SerializationUtils.serialize(message));

}

}

Register Encoders

Client: @ClientEndpoint(encoders = {Menc.class, Menc2.class})

Server: @ServerEndpoint(encoders = {Menc.class, Menc2.class})

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WebSocket Decoder

public class MessageDecoder implements Decoder.Binary<Message> {

public Message decode(ByteBuffer b) throws DecodeException {

return (Message) SerializationUtils.deserialize(b.array()); }

public boolean willDecode(ByteBuffer b) {

return true }

}

Register Decoders

Client: @ClientEndpoint(decoders = {MessageDecoder.class, Dec.class})

Server: @ServerEndpoint(decoders = {MessageDecoder.class, Dec.class})

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WebSocket @PathParam

• Annotate one or more parameters on:

• @OnMessage, @OnError, @OnClose, @OnOpen

@ServerEndpoint("/bookings/{id}")

public class BookingEndpoint {

@OnMessage

public void handle(@PathParam(“id”) String id,

Message m, Session s) {}

}

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WebSockets – sending messages

• BUT… how to send messages?

• BasicRemote: blocking until message has been transmitted• session.getBasicRemote().sendObject(message);

• AsyncRemote: fire and forget• Future<Void> v =

session.getAsyncRemote().sendObject(message);

• Progress may be tracked using the Future Object

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WebSockets – Broadcasting messages

• interaction with other Sessions

• Identify Sessions by ID

• Only Sessions in same Endpoint are accessible

• Sessions only accessible trough Session:

• session.getOpenSessions()

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Best Practice

• No automatic reconnection:

• Use OnError to reconnect

• Use Session.getUserProperties() to store additional informations

• Server Endpoitns have full support for CDI and @Inject

• Endpoint can be @Singleton / @Stateless… but requirement was

removed from spec!

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Best Practice

• One handling method per type!:

• Each websocket endpoint may only have one message handling

method for each of the native websocket message formats.

• Solution: inherence, Enums,…

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@OnMessage

public void onAddUser(AddUser user) {

}

@OnMessage

public void onMessage(Message m) {

}

@OnMessage

public void onChatMessage(Message chatMessage) {

switch (chatMessage.getType()){

case MESSAGE:

break;

case ADD_USER:

break;

}

}

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WebSockets

Any questions?

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SSE / WebSockets in Enterprise

SSE / WebSockets in Enterprise

Securtity

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Security – Jersey 2 SSE

• Basic authentication - Jersey 2 way:

Client client = ClientBuilder.newBuilder().build();

WebTarget webTarget = client.target(restURL);

webTarget.register(new HttpBasicAuthFilter(user, pwd));

• Easy SSL konfigurations

SslConfigurator sslConfig =

SslConfigurator.newInstance()

.keyStoreFile("keystore.jks")

.keyPassword("asdfgh")

.scurityProtocol("SSL");

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Security – WebSocket (Tyrus API)

• Initial handshake over HTTP/HTTPS (ws:// | wss://)

• Session.getPrincipal() available

BUT….

NO Client API for authentication!

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Security – WebSocket (Tyrus API)

• Authentication is nevertheless possible (request properties)

c = new ClientEndpointConfig.Configurator() {

public void beforeRequest(Map<String, List<String>> headers)

{

headers.put("Authorization",

Arrays.asList("Basic " + BASE64Enc.encode(encPwd))));

}

};

config = ClientEndpointConfig.Builder.

create().

configurator(c).build();

client.connectToServer(CEndpoint.class, config, “ws://…/endpoint");

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Loadbalancing - SSE

• Works with mod_proxy / mod_jk

• Problem: notification of EventOutput on each Cluster-Node (Broadcast)

• Workaround: bypass the LB and notify the nodes

• Duplicate messages to other nodes

• Use JMS to notify all nodes in cluster

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Failover SSE

• On connection drop:

• Error event

• Try to reconnect

• default wait before trying to reconnect is 3 seconds

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Failover WebSockets

• No Session replication available in current (Tyrus) version!

• Use @OnError to reconnect on failure

• Do NOT use properties on Session

• Problem: message broadcasting

• Set LB weight 100 to one Node

• Ensure that all sessions on one Node

• Duplicate messages to other nodes

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SSE vs. WebSockets

• send/receive data from client

• provide true real-time

updates

• require servers that

understand the protocol

• Can identify peers (by ID)

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• push data to client

• can be configured to provide

close to real-time

• sent over traditional HTTP, so

no modification is required

• Can identify events (by ID)

WebSocket Server-Sent Events

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JEE 7 project overview

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• Client API - using builder pattern

• asynchronous request processing

Future<String> future =

client.target("http://...").pathParam("", "")

.request("text/plain").async().get(..);

[4]

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Example project with MongoDB

replication in Bitbucket (see Demos)

[4]

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@Resource(lookup = "jms/connectionFactory")

ConnectionFactory connectionFactory;

@Resource(lookup="jms/inboundQueue")

Queue inboundQueue;

public void sendMessageNew (String payload) {

try (JMSContext context = connectionFactory.createContext();)

{

context.send(inboundQueue,payload);

}

}

[4]

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@Resource(name = "concurrent/myExecutor")

ManagedExecutorService executor;

executor.execute(new MyRunnableTask(2));

[4]

2013 © Trivadis


VIELEN DANK.Andy Moncsek

[email protected]

www.trivadis.com

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mailto:[email protected]

2013 © Trivadis

Appendix

1. Wallpaper: http://bensow.deviantart.com/art/Wallpaper-Under-Construction-

252593627

2. http://de.slideshare.net/MasoudKalali/server-sent-events-async-servlet-web-

sockets-and-json-born-to-work-together

3. Tyrus Project: http://java.net/projects/tyrus

4. Jersey 2: http://jersey.java.net/jersey20.html

5. JacpFX: https://code.google.com/p/jacp/

6. GlassFish 4 downloads: http://glassfish.java.net/public/downloadsindex.html

7. [3] http://blog.exceliance.fr/2012/11/07/websockets-load-balancing-with-

haproxy/

8. [4] http://de.slideshare.net/arungupta1/the-java-ee-7-platform-productivity-

html5-16124993

9. http://download.oracle.com/otndocs/jcp/websocket-1_0-pfd-spec/index.html

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http://bensow.deviantart.com/art/Wallpaper-Under-Construction-252593627








http://de.slideshare.net/MasoudKalali/server-sent-events-async-servlet-web-sockets-and-json-born-to-work-together




























http://jersey.java.net/jersey20.html

http://jersey.java.net/jersey20.html

https://code.google.com/p/jacp/

https://code.google.com/p/jacp/

http://glassfish.java.net/public/downloadsindex.html

http://blog.exceliance.fr/2012/11/07/websockets-load-balancing-with-haproxy/










http://de.slideshare.net/arungupta1/the-java-ee-7-platform-productivity-html5-16124993
















http://download.oracle.com/otndocs/jcp/websocket-1_0-pfd-spec/index.html








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