java ee 7 from an html5 perspective - doag

JAVA EE 7 FROM AN HTML5 PERSPECTIVE

Ed Burns @edburns and Oliver Szymanski @source_knights

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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


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¨  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


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¨  Author of four books for McGraw-Hill

Speaker Qualifications – Oliver Szymanski


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¨  Independent Java Enterprise Consultant ¨  Specialty in the Financial Sector ¨  JUG Founder Erlangen/Nuremberg Germany

Speaker Qualifications – Oliver Szymanski


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¨  Contributing author for ¤ Heise Developer Channel ¤ S&S Entwickler ¤ Java aktuell ¤ Java Magazin

Meet the Family


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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

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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

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HTML5 Why all the fuss?

More cute logos at http://www.w3.org/html/logo/

HTML5 Why 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


Java API for RESTful Web Services 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);! }! });! }!}!

Java API for RESTful Web Services 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


Java Message Service 2.0

¨  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

Java Message Service 2.0 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

Java Message Service 2.0 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 è1 line!

Java Message Service 2.0 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) ¤ Server: 43 pages

What’s In a name?

WebSockets

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

WebSocket Establish the connection

WebSocket TCP over HTTP, use the Upgrade: header

WebSocket Browser 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 Client JavaScript 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 HandshakeRequest!

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.ServerContainer attribute

¤  It will be an instance of javax.websocket.server.ServerContainer!

¤ Call addEndpoint(), two variants n  takes a class that is the annotated endpoint class n  takes a ServerEndpointConfig instance

Programmatic Endpoint

Java Server Annotated 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

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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 you 67


java ee 7 from an html5 perspective - doag

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