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Effective JavaFX architecture with FxObjects


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Developing enterprise applications today using JavaFX is a challenge. The industry has not matured enough to identify patterns and practices. Consequently practioners (architects and developers alike) commit the same mistakes again and again. There is a complete lack of non-UI frameworks that make JavaFX application development easy and fast. FxObjects attempts to address that gap. The 0.1 version released provides powerful features.

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Effective JavaFX architecture with FxObjects

  1. 1. Effective JavaFX Architecture with Presented by Srikanth Shenoy ObjectSource (Covers FxObjects 0.1)
  2. 2. Introduction  Who am I?  A hands-on architect  Experienced and very knowledgeable in Java and Java EE  Authored a book on Struts  Several articles on Java EE for leading journals  Director of Enterprise Java Practice at ObjectSource  Creator of FxObjects framework
  3. 3. Introduction  What is FxObjects? (Currently 0.1)  An open source JavaFX application development framework (Apache License)  Why FxObjects?  Enterprise JavaFX architect/developer starts from scratch, reinventing the wheel, wasting time and repeating mistakes  Enterprise JavaFX applications need a strategic and functional framework (not a point solution).  FxObjects is that strategic functional framework !  Learn FxObjects in 25 slides !
  4. 4. 30K ft. Overview
  5. 5. Introduction  FxObjects is the end to end application development framework in the UI tier.  Designed to simplify large JavaFX application development  Makes your application elegant by using proven patterns, principles and practices  If you use FxObjects as defined in the user guide, your application becomes inherently test friendly
  6. 6. Introduction  FxObjects is Dependency Injection (DI) friendly from the grounds-up.  Tested with Spring 2.5  Dependency Injection + FxObjects makes a very powerful and agile programming model  FxObjects makes TDD possible with JavaFX by using Model-View-Presenter (MVP)  FxObjects is NOT a UI component library (and never intends to be).
  7. 7. Model-View-Presenter (Passive View)  Note the sequence of events in MVP passive View  Actual UI is lean, mean and clean   Presenter does the heavy lifting on the UI side. But Presenter is not really a UI !!  Hence Presenter can be easily tested and asserted
  8. 8. MVP with FxObjects  NodePresenter is the FxObjects class.  MyNodePresenter and MyNode are app classes & hold reference to each other  When a event occurs, the MyNode simply calls doOnSearchButtonClick()
  9. 9. Presenter Code  doSearchButtonClick method  Validates UI (for mandatory fields)  Calls the service asynchronously using FxObjects Command classes  That’s it!  You will see FxObjects Commands next  For aiding the async service calls  Update the UI when async calls return data  Show error message when service call fails
  10. 10. Challenges in Service Invocation  Async calls are fire and forget  They should execute off the Event Dispatch Thread (EDT)  All UI updates should then again occur ON the EDT.  Can be confusing and errror-prone  Swing provided SwingWorker  JavaFX provides a async framework  Slightly complex, but FXObjects simplifies this
  11. 11. JavaFX Async Framework
  12. 12. Challenges in Service Invocation (contd.)  HttpRequest (core JavaFX class) has some solution (async call is off-EDT & callbacks are on-EDT), but it is the foundation for a full solution  FxObjects HttpCommands provide the missing pieces to make this simple  How to easily go to another page v/s stay on same page after service invocation?  FxObjects solves this, as we shall see soon (controller chain)
  13. 13. Command objects  Command objects are configured first and then executed [with execute(..) method] var cmd = DefaultAsyncCommand { runInBackground: function(modelObj:Object):Object { //call service here } onSuccess: function(resultObj:Object):Void { //update ui widgets here OR navigate to another UI } onError: function(e:Exception):Void { //show the error } }
  14. 14. Automating XML to JavaFX  No Xml tag handling code necessary  Use XmlResponseBuilder  Called ResponseBuilder since it was initially built to construct JavaFX objects from XML content (returned by REST services)  Can handle XML of any type and of any depth  Scales well for all kinds of xml  Best suited for small JavaFX apps though  Larger apps can use JAXBResponseBuilder
  15. 15. Automating JavaFX to XML  No code necessary  Use XmlRequestBuilder  Called RequestBuilder since it was initially built to construct XML from JavaFX objects to be sent as request body to REST services  Can handle JavaFX objects of any type and of any depth  Scales well for JavaFX objects of any kind  Best suited for small JavaFX apps  Larger apps can use JAXBRequestBuilder
  16. 16. HttpCommands and Builders  Just like DefaultAsyncCommand  No runInBackground necessary. [Http GET/POST themselves run in background !!]  Url & query parameters are configurable with { } syntax  e.g. http://server/app/search?zipCode={zipCode}  The params in {} can be passed in a Map  Otherwise reflection is used to query the object  Need RequestBuilder and ResponseBuilder  XML***Builder or JAXB***Builder
  17. 17. GetHttpCommand var respBuilder = new MyJAXBResponseBuilder(); respBuilder.setSchema(…); var cmd = GetHttpCommand { urlTemplate: “http://.../Search?output=xml&zip={zipCode}&.. responseBuilder: respBuilder onSuccess: function(resultData:Object) { var result = resultData as ResultSet; //update UI components here OR navigate to another UI } onError: function(e:Exception) { .. } } .. function doSearchButtonClick() { var paramMap = new HashMap(); paramMap.put(“zipCode”, node.zipCodeTxtBox.text); cmd.execute(paramMap); }
  18. 18. Custom JAXB Response Builder public class CafeSearchResponseBuilder extends JAXBResponseBuilder<ResultSet> { @Override public ResultSet buildResponse(String serverResponse) { ResultSet rs = buildResponseObjectFromXml(serverResponse); return rs; } @Override public ResultSet buildResponse(InputStream inputStream) { ResultSet rs = buildResponseObjectFromXml(inputStream); return rs; } }
  19. 19. BodyHttpCommand  Use for PUT and POST  Almost same as GetHttpCommand  Additionally needs RequestBuilder  To convert the presentation model object into format expected by server (Generaly XML)  Optionally a content pre-processor  To massage the output from the requestbuilder and before sending to server
  20. 20. Navigation challenges  How to go to another page v/s stay on same page after service invocation succeeds?  Default JavaFX model involves binding to a new scenegraph  Couples the lower level UI to top level stage.  No idioms for organizing the application into modules  Who decides what is the default node to display?  Solution: FxObjects ControllerChain
  21. 21. Controller Chain
  22. 22. Navigation with FxObjects Controller Chain  Each Application can hold many Presenters  Each Application can have many Modules  Each Module can hold many Presenters  Application has a Application Controller  Each Module has a Module Controller.  Module Controller has a Id  Each NodePresenter owns the Node  Node Presenter has a Id
  23. 23. Navigation with FxObjects Controller Chain (contd.) public MyNodePresenter extends NodePresenter var cmd = DefaultAsyncCommand { runInBackground:function(modelObj:Object):Object { //call service here } onSuccess: function(resultObj:Object):Void { //update ui here OR go to another page this.changeNodePresenter(“someNodePresenterId”); } onError: function(e:Exception):Void { //show the error } } changeNodePresenter(..) is defined in NodePresenter class (the parent)
  24. 24. FxObjects and Dependency Injection  FxObjects is built with Dependency Injection in mind.  DI is optional, but recommended  What can be wired  ApplicationController, ModuleController  NodePresenter (but not Nodes)  Commands, Services (Service Proxies)  Nodes should be maintained by Presenters.  This lets presenters choose appropriate node handling strategy (cache, dispose after use etc.)
  25. 25. Bootstrapping FxObjects var ctx = new ClassPathXmlApplicationContext(“/your-spring.xml"); var appController = ctx.getBean("appController") as ApplicationController; Stage { title: "FxObjects Example“ scene: Scene { width: 600 height: 400 content: bind [ appController.currentNodePresenter.getNode() ] } }  Node presenter configured as default is shown at the beginning  Every navigation call sets another NodePresenter as the “Current” NodePresenter and that gets bound to the scenegraph
  26. 26. What’s coming in 0.2?  Lifecycle  Event  Event Bus  Security  JSON to JavaFX round-tripping  Suggestions welcome (Please post in the discussion forums)  Timeframe: September 2010
  27. 27. FxObjects Summary  Enterprise JavaFX applications are inherently complex.  Architecting such apps is art and science  FxObjects can help  The more complex the application, the more value you get from FxObjects  End to end programming model for the UI  Does not force any programming model for the server
  28. 28. Links  Project site – https://fxobjects/  Not a single person open source project  FxObjects is developed and supported by ObjectSource (  Download, use, extend, redistribute, OEM  Discussion Forums on project site  We will answer your questions  Participation welcome  Post ideas, questions, concerns, comments  Contribute code