JAVA EE 7 FROM AN HTML5 PERSPECTIVE. Ed and Oliver

Transcription

1 JAVA EE 7 FROM AN HTML5 PERSPECTIVE Ed and Oliver

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. 2 Copyright 2015 Ed Burns and Oliver Szymanski

3 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 Copyright 2015 Ed Burns and Oliver Szymanski

4 Speaker Qualifications Ed Burns 4 Author of four books for McGraw-Hill Copyright 2015 Ed Burns and Oliver Szymanski

5 Speaker Qualifications Oliver Szymanski 5 Independent Java Enterprise Consultant Specialty in the Financial Sector JUG Founder Erlangen/Nuremberg Germany Copyright 2015 Ed Burns and Oliver Szymanski

6 6 Speaker Qualifications Oliver Szymanski Contributing author for Heise Developer Channel S&S Entwickler Java aktuell Java Magazin Copyright 2015 Ed Burns and Oliver Szymanski

7 Meet the Family 7 Copyright 2015 Ed Burns and Oliver Szymanski

8 Meet the Family 8 Java API for JSON Processing Java API for WebSocket Batch Application Concurrency Utilities Caching Java Persistence Architecture Java API for REST JavaServer Faces Servlets Copyright 2015 Ed Burns and Oliver Szymanski Expression Language Java Messaging Service Contexts and Dependency Injection Java Transaction Architecture

9 Meet the HTML5-Friendly Family 9 Java API for JSON Processing Java API for WebSocket Batch Application Concurrency Utilities Caching Java Persistence Architecture Java API for REST JavaServer Faces Servlets Copyright 2015 Ed Burns and Oliver Szymanski Expression Language Java Messaging Service Contexts and Dependency Injection Java Transaction Architecture

10 HTML5 Why all the fuss? More cute logos at

11 HTML5 Why all the fuss? PAST AND PRESENT SERVER

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

14 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.

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16 HTML5 What s in a name? Remember all the fuss about Ajax in 2006? Asynchronous JavaScript And XMLHttpRequest

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

18 HTML4 What s in a name? 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

19 HTML5 What s in a name? 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 n Canvas n Input controls n Web components n Application Cache n WebSocket n JSON n Geolocation n XMLHttpRequest Level 2

20 HTML5 Is it really a big deal? 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.

21 HTML5 Is it really a big deal? The death of the browser plugin: April Where does the tension remain? Take advantage of the power in the client Minimize the complexity of distributing and maintaining the software

22 HTML5 Putting it in context 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

23 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

24 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

25 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

26 HTML5 Friendly Markup The best part of Wicket comes to JSF This is a JSF page <!DOCTYPE html>! <html xmlns=" xmlns:myns=" >! <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>!!

27 HTML5 Friendly Markup Let s get back to basics 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`

28 HTML5 Friendly Markup Let the elegance of HTML shine through 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.

29 HTML5 Friendly Markup 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

30 JSR 341 Expression Language 3.0 Overview 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

31 JSR 341 Expression Language 3.0 New Feature Summary Lambda expressions Support for stand-alone environments New operators Static field and method reference Custom type converter Collection construction Collection operations

32 JSR 341 Expression Language 3.0 Lambda expression 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 x -> x+1! (x,y) -> x+y! () -> 64!

33 JSR 341 Expression Language 3.0 Lambda expression: immediate evaluation The lambda is evaluated and discarded (x -> x+1)(10)!!à 11! ((x,y)->x+y)(3,4)!à 7! (()->64)()!!à 64!

34 JSR 341 Expression Language 3.0 Collection operations: examples 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>!

35 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

36 Java API for JSON Processing 1.0 Overview JSR 353 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

37 Java API for JSON Processing 1.0 Streaming API 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,

38 Java API for JSON Processing 1.0 Object Model 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

39 Java API for RESTful Web Services 2.0 Overview JSR 339 Client API Message Filters & Entity Interceptors Asynchronous Processing Server & Client Hypermedia Support Common Configuration

40 Java API for RESTful Web Services 2.0 Server-side public class MyResource public void AsyncResponse ar) {!! ar.settimeouthandler(new MyTimoutHandler());! ar.settimeout(15, SECONDS);!! Executors.newSingleThreadExecutor().submit(new Runnable() {! public void run() {!! ar.resume(result);! }! });! }! }!

41 Java API for RESTful Web Services 2.0 Server-side Content class "application/json"}) public Product[] getproducts() {... } }!

42 Java Message Service 2.0 Overview JSR 343 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

43 Java Message Service 2.0 Auto close resources Make JMS objects implement AutoCloseable! Connection! Session! MessageProducer! MessageConsumer! QueueBrowser! Requires Java SE 7

44 Java Message Service 2.0 Auto close = "jms/connfactory") ConnectionFactory cf;! Create closeable resources in a trywith-resources 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! } close() is called }! automatically at end of block

45 Java Message Service 2.0 Introducing JMSContext JMSContext combines Connection and = "java:global/jms/democonnectionfactory")! ConnectionFactory = "java:global/jms/demoqueue")! Payload Queue demoqueue;! can be sent! directly public void sendmessage (String payload) {! try (JMSContext context = connectionfactory.createcontext();){! context.createproducer().send(demoqueue, payload);! } catch (JMSRuntimeException ex) {! // exception handling! }! }! No checked exceptions thrown close() is called automatically at end of block

46 Java Message Service 2.0 Default Data Source JMSContext context;!! Default resource = "java:global/jms/demoqueue ) Queue demoqueue;!! public void sendmessage(string payload) {! context.createproducer().send(demoqueue, payload);! }! 13 lines è 1 line!

47 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

48 WebSockets What s In a name? Several moving parts, each with its own standard! Client: W3C JavaScript API websockets/ Transport: IETF RFC rfc6455.txt Server: JSR-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)

49 WebSockets

50 WebSocket Big Picture 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

51 WebSocket Establish the connection

52 WebSocket TCP over HTTP, use the Upgrade: header

53 WebSocket TCP over HTTP, use the Upgrade: header

54 WebSocket TCP over HTTP, use the Upgrade: header

55 WebSocket Browser Support caniuse.com

56 JavaScript/Browser Client JavaScript WebSocket Object 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

57 JavaScript/Browser Client JavaScript WebSocket Object [Clamp] if value is out of range, truncate it to closest inrange value for that primitive type.

58 Java Server Java Endpoint 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

59 Java Server Java Endpoint Passing Parameters example URI /bookings/johnsmith : guestid is JohnSmith Strings and primitives supported

60 Java Server Java Endpoint 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

61 Java Server Programmatic Endpoint 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

62 Java Server Annotated Endpoint

63 Java Server Annotated Endpoint

64 Java Server Programmatic Endpoint The ServerEndpointConfig instance getendpointclass() returns n annotated endpoint n class that extends javax.websocket.endpoint! getpath() returns the path, may contain urltemplate content

65 WebSocket Flexible Message Processing 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

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. 66 Copyright 2015 Ed Burns and Oliver Szymanski

67 67 Thank you Copyright 2015 Ed Burns and Oliver Szymanski