Java EE 7 from an HTML5 Perspective, JavaLand 2015

JAVA EE 7
FROM AN HTML5 PERSPECTIVE
Ed Burns @edburns and Oliver Szymanski @source_knights

2
Safe Harbor Statement
The following is intended to outline our general product direction. It is
intended for information purposes only, and may not be incorporated
into any contract. It is not a commitment to deliver any material, code,
or functionality, and should not be relied upon in making purchasing
decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole
discretion of Oracle.
Copyright 2015 Ed Burns and Oliver Szymanski

Speaker Qualifications – Ed Burns
3
¨  Involved with JSF since 2002
¨  JSF Spec lead since 2003
¤  Most fun part of the job: cleanly integrating other
people’s great ideas into JSF (and hopefully improving
on the in the process)
¤  Not an expert in applying JSF in practice
¨  Servlet Spec lead since 2014

Speaker Qualifications – Ed Burns
4
¨  Author of four books for McGraw-Hill

Speaker Qualifications – Oliver Szymanski
5
¨  Independent Java Enterprise Consultant
¨  Specialty in the Financial Sector
¨  JUG Founder Erlangen/Nuremberg Germany

Speaker Qualifications – Oliver Szymanski
6
¨  Contributing author for
¤  Heise Developer Channel
¤  S&S Entwickler
¤  Java aktuell
¤  Java Magazin

Meet the Family
7

Meet the Family
¨  Java API for JSON
Processing
¨  Java API for
WebSocket
¨  Batch Application
¨  Concurrency Utilities
¨  Caching
¨  Java Persistence
Architecture
¨  …
¨  Java API for REST
¨  JavaServer Faces
¨  Servlets
¨  Expression Language
¨  Java Messaging
Service
¨  Contexts and
Dependency Injection
¨  Java Transaction
Architecture
8

Meet the HTML5-Friendly Family
¨  Java API for JSON
Processing
¨  Java API for
WebSocket
¨  Batch Application
¨  Concurrency Utilities
¨  Caching
¨  Java Persistence
Architecture
¨  …
¨  Java API for REST
¨  JavaServer Faces
¨  Servlets
¨  Expression Language
¨  Java Messaging
Service
¨  Contexts and
Dependency Injection
¨  Java Transaction
Architecture
9

HTML5Why all the fuss?
More cute logos at
http://www.w3.org/html/logo/

HTML5Why all the fuss?
PAST AND PRESENT
SERVER

Classification
¨  Why?
¤  Multiple Computers
¤  Interconnections Between Them
¤  Shared State Among Them
¨  Today's production Web apps are extremely
complex distributed applications.
A Web App is a Distributed App

Yeah, So What?
¨  Why does this classification matter?
¤  Because History Matters
¨  To understand the current state of web applications,
we must go back to the history of distributed
applications, and of the Internet itself.

HTML5
¨  Remember all the fuss about Ajax in 2006?
¤  Asynchronous
¤  JavaScript
¤  And
¤  XMLHttpRequest
What’s in a name?

HTML5
¨  Remember all the fuss about Ajax in 2006?
¤  Asynchronous
¤  JavaScript
¤  And
¤  XMLHttpRequest
¨  Ajax is a programming technique, not a single
technology
What’s in a name?

HTML4
¨  What do people mean when they say HTML4?
¤  IE6
¤  Not very high performance JavaScript
¤  Lots of browser tricks
¤  Use of native plugins is common
¨  HTML4 is seen as a single technology
What’s in a name?

HTML5
¨  What do people mean when they
say HTML5?
¤  “Modern” browsers
¤  A gigantic collection of related
technologies
n  Markup
n  Offline storage
n  EventSource
n  DOM
n  JavaScript
n  CSS3
What’s in a name?
n  Canvas
n  Input controls
n  Web components
n  Application Cache
n  WebSocket
n  JSON
n  Geolocation
n  XMLHttpRequest
Level 2

HTML5
¨  The rise of Chrome and the end of polyfill
¨  Standards have finally won
¤  How good is your standards body?
n  W3C, ECMA, IETF
¤  HTML5: Microsoft, Google, Apple, what about Mozilla?
¨  Aside:
¤  Is HTML5 a bloated specification?
¤  Is JavaEE a bloated specification?
¤  What is bloat? A indicator of how old something is.
¤  http://mir.aculo.us/2010/10/19/standards-bloat-and-
html5/
Is it really a big deal?

HTML5
¨  The death of the browser plugin: April 2010
http://www.apple.com/hotnews/thoughts-on-flash/
¨  Where does the tension remain?
¤  Take advantage of the power in the client
¤  Minimize the complexity of distributing and maintaining
the software
Is it really a big deal?

HTML5
¨  HTML5 is a marketing term that describes a way of
building the UI for a distributed system.
¤  UI processing task resides entirely in the browser
Putting it in context

What Makes a Distributed App
¨  Finding the best allocation of processing tasks to
processing nodes
¤  User Interface
¤  Domain Logic
¤  Application Logic
¤  Data Persistence
¤  Communication
¤  Reliability, Security

UI Considerations
¨  The UI is the hardest part to get right
¨  The technology for building the UI is changing very
rapidly, and will continue to change for the
forseeable future
¨  The technology for the other aspects of application
development is less volatile, more mature.
¨  The major software stack and device vendors are
competing on the basis of their UI technology, as the
gateway to the rest of their stack

HTML5 Friendly Markup
¨  This is a JSF page
The best part of Wicket comes to JSF
<!DOCTYPE html>!
<html xmlns="http://www.w3.org/1999/xhtml"!
xmlns:myNS="http://xmlns.jcp.org/jsf”>!
<form myNS:id="form">!
<input name="textField" type="text" myNS:value="#{bean.text1}" />!
<input type="submit" myNS:id="submitButton" value="submit" /> !
<p>submitted text: #{bean.text1}.</p>!
</form>!
</html>!
!

¨  JSF Views are written in a View Declaration
Language (VDL).
¨  The standard Facelet VDL is an XML application with
two kinds of elements
¤  HTML Markup
¤  JSF Components
¨  HTML Markup is passed through straight to the
browser
¨  JSF Components take some action on the server,
during the lifecycle`
Let’s get back to basics

¨  Before JSF 2.2
¤  JSF tags hide complexity of underlying HTML+script+css
+images
¤  JSF “Renderer”:
n  encode: markup to browser
n  decode: name=value from browser
<html>…
<my:colorPicker value=“#{colorBean.color2}” />
<my:calendar value=“#{calendarBean.date1}” />
</html>
¨  Context: Missing feature in browser? Write a JSF
component.
Let the elegance of HTML shine through

¨  With JSF 2.2
¤  Pure HTML+script+css+images in the JSF page
¤  JSF Renderer handles decode from browser
n  Leverage the strength of the JSF lifecycle
n  Leverage the expressiveness of HTML5
<html>…
<input type=“color” jsf:value=“#{colorBean.color2}”/>
<input type=“date” jsf:value=“#{calendarBean.date1}” />
</html>
¨  Context: New feature in browser? Use “pass through
elements”
Let the elegance of HTML shine through

JSR 341 Expression Language 3.0
¨  First introduced in JSTL 1.0 in 2004
¨  Moved to JSP 2.0 in 2006
¨  Unified with JSF 1.2 in JSP 2.1 in 2006
¨  JSR 341: first independent specification in 2013
¨  Used in JSF, JSP and CDI
¨  Key differentiator between JavaServer and non-
JavaServer stacks
Overview

¨  Lambda expressions
¨  Support for stand-alone environments
¨  New operators
¨  Static field and method reference
¨  Custom type converter
¨  Collection construction
¨  Collection operations
New Feature Summary

¨  Same syntax as JavaSE 8, but available in EE 7
¨  Behaves like an anonymous function
¨  Body consist of an EL expression
¨  Full access to EL environment in the body
Lambda expression
x -> x+1!
(x,y) -> x+y!
() -> 64!

¨  The lambda is evaluated and discarded
Lambda expression: immediate evaluation
(x -> x+1)(10)! !à 11!
((x,y)->x+y)(3,4) !à 7!
(()->64)() ! !à 64!

¨  JSF Facelet page
<h:dataTable rendered=!“#{user.loggedIn}” 
value="#{library.books.stream(). 
filter(b->b.category == 'Comedy'). 
map(b->b.title).toList()}" var="book">!
<h:column>#{book.title}</h:column>!
</h:dataTable>!
Collection operations: examples

Java API for JSON Processing 1.0
¨  API to parse and generate JSON
¨  Streaming API
¤  Low-level, efficient way to parse/generate JSON
¤  Provides pluggability for parsers/generators
¨  Object Model
¤  Simple, easy-to-use high-level API
¤  Implemented on top of Streaming API
¨  Binding JSON to Java objects forthcoming
Overview – JSR 353

¨  Parses JSON in a streaming way from input sources
¤  Similar to StaX’s XMLStreamReader, a pull parser
¨  Created using
¤  Json.createParser(…)!
¤  Json.createParserFactory().createParser(
…)!
¨  Parser state events
¤  START_ARRAY, END_ARRAY, START_OBJECT,
END_OBJECT, …
Streaming API

¨  JsonObject/JsonArray – JSON object and
array structures
¤  JsonString and JsonNumber for string and
number values
¨  JsonBuilder – Builds JsonObject and JsonArray
¨  JsonReader – Reads JsonObject and JsonArray
from input source
¨  JsonWriter – Writes JsonObject and JsonArray
to output source
Object Model API

Java API for RESTful Web Services
2.0
¨  Client API
¨  Message Filters & Entity Interceptors
¨  Asynchronous Processing – Server & Client
¨  Hypermedia Support
¨  Common Configuration

2.0
Server-side Async
@Path("/async/longRunning")!
public class MyResource { !
!
@GET!
public void longRunningOp(@Suspended AsyncResponse ar) {!
!
ar.setTimeoutHandler(new MyTimoutHandler());!
ar.setTimeout(15, SECONDS);!
!
Executors.newSingleThreadExecutor().submit(new Runnable() {!
public void run() { !
…!
ar.resume(result);!
}!
});!
}!
}!

2.0
Server-side Content Negotiation
@Path("/") 
class ProductResource {!
    @GET 
    @Produces({"text/xml;qs=0.75", "application/json"}) 
    public Product[] getProducts() { 
        . . . 
    } 
}!

Java Message Service 2.0
¨  Less verbose
¨  Reduce boilerplate code
¨  Resource injection
¨  Connection, Session, and other objects are
AutoCloseable
¨  Requires Resource Adapter for Java EE containers
¨  Simplified API in both Java SE and EE

¨  Make JMS objects implement AutoCloseable!
¤  Connection !
¤  Session !
¤  MessageProducer !
¤  MessageConsumer !
¤  QueueBrowser!
¨  Requires Java SE 7
Auto close resources

@Resource(lookup = "jms/connFactory") 
ConnectionFactory cf; !
@Resource(lookup="jms/inboundQueue")!
Destination dest;!
!
public void sendMessage (String payload) throws JMSException {!
try ( Connection conn = connectionFactory.createConnection(); !
Session session = conn.createSession();!
MessageProducer producer = session.createProducer(dest);!
){ !
Message mess = sess.createTextMessage(payload); !
producer.send(mess); !
} catch(JMSException e){ !
// exception handling !
} 
}!
Create closeable
resources in a try-
with-resources block
close() is called
automatically
at end of block
Auto close resources

@Resource(lookup = "java:global/jms/demoConnectionFactory")!
ConnectionFactory connectionFactory; !
!
@Resource(lookup = "java:global/jms/demoQueue")!
Queue demoQueue;!
!
public void sendMessage (String payload) {!
try (JMSContext context = connectionFactory.createContext();){!
context.createProducer().send(demoQueue, payload);!
} catch (JMSRuntimeException ex) {!
// exception handling!
}!
}!
close() is called
automatically
at end of block
JMSContext
combines
Connection
and Session
Payload
can be sent
directly
No checked
exceptions
thrown
Introducing JMSContext

@Inject 
JMSContext context;!
!
@Resource(lookup = "java:global/jms/demoQueue”) 
Queue demoQueue;!
!
public void sendMessage(String payload) {!
context.createProducer().send(demoQueue, payload);!
}!
Default resource definition
Or
@JmsConnectionFactory!
13 lines è1 line!
Default Data Source Definition

WebSockets
¨  Several moving parts, each with its own standard!
¤  Client: W3C JavaScript API http://dev.w3.org/html5/
websockets/
¤  Transport: IETF RFC 6455 http://www.ietf.org/rfc/
rfc6455.txt
¤  Server: JSR-356: http://jcp.org/en/jsr/detail?id=356
¨  Even with all these parts, it’s still very
understandable
¤  Client: 17 page downs
¤  Transport: 86 page downs (about a third of which you
can skip)
What’s In a name?

WebSocket
¨  It really is a Socket for the Web
¤  It just works over proxies
¨  Lets you do TCP easily in a web app
¤  Establish the connection
¤  Send messages both ways
¤  Send messages independent of timing
¤  Close the connection
¨  Two basic types: text and binary
Big Picture

WebSocketEstablish the connection

WebSocketTCP over HTTP, use the Upgrade: header

WebSocketBrowser Support – caniuse.com

JavaScript/Browser Client
¨  Minimal Lifecycle
¤  new WebSocket(url)!
¤  pass in some functions
n  onopen!
n  onmessage!
¤  call send()!
¤  call close() !
¨  Can connect to arbitrary servers, other than the
page origin
¨  Server may enforce use of Origin header
JavaScript WebSocket Object

JavaScript/Browser ClientJavaScript WebSocket Object
¨  [Clamp] if
value is out of
range,
truncate it to
closest in-
range value
for that
primitive type.

Java Server
¨  Minimal Lifecycle
¤  Handshake
¤  Messaging
¤  Close
¨  All methods that deal with communication to the
other endpoint are passed a
javax.websocket.Session.
¨  Has nothing to do with
javax.servlet.http.HttpSession.
¨  HttpSession can be obtained from
Java Endpoint

Java Server
¨  Passing Parameters
¨  example URI “/bookings/JohnSmith”: guestID is
“JohnSmith”
¨  Strings and primitives supported
Java Endpoint

Java Server
Two Styles
¨  Annotated
¤  The most commonly used
¤  Very easy to get started
¤  Throw it in the WAR and you’re done
¨  Programmatic
¤  If you don’t want to bake config into your .class files
¤  Must use Java inheritance
Java Endpoint

Java Server
¨  Must bootstrap via ServletContextListener!
¤  Look up the
javax.websocket.server.ServerContaine
r attribute
¤  It will be an instance of
javax.websocket.server.ServerContaine
r!
¤  Call addEndpoint(), two variants
n  takes a class that is the annotated endpoint class
n  takes a ServerEndpointConfig instance
Programmatic Endpoint

Java Server
¨  The ServerEndpointConfig instance
¤  getEndpointClass() returns
n  annotated endpoint
n  class that extends javax.websocket.Endpoint!
¤  getPath() returns the path, may contain url-
template content
Programmatic Endpoint

WebSocket
¨  Send or receive text or binary messages
¤  As complete messages
¤  As sequence of partial messages
¤  Using traditional blocking I/O
¨  Send or receive WebSocket messages as pure Java
Objects (kinda like Serialization)
¤  Using encode/decode mechanism
¤  Encoder/decoder for all primitive types built in
¨  Send and receive messages synchronously or
asynchronously
Flexible Message Processing

66
Safe Harbor Statement
The preceding was intended to outline our general product direction. It
was intended for information purposes only, and may not be
incorporated into any contract. It was not a commitment to deliver any
material, code, or functionality, and should not be relied upon in
making purchasing decisions. The development, release, and timing of
any features or functionality described for Oracle’s products remains
at the sole discretion of Oracle.

Thank you67

Java EE 7 from an HTML5 Perspective, JavaLand 2015

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Java EE 7 from an HTML5 Perspective, JavaLand 2015