Effective JavaFX architecture with FxObjects

Effective JavaFX

Architecture with

Presented by

Srikanth Shenoy

ObjectSource

(Covers FxObjects 0.1)

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

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 !

30K ft. Overview

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

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).

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

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()

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

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

JavaFX Async Framework

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)

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

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

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

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

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);

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;

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

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

Controller Chain

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

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)

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.)

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

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

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

Links

Project site – https://fxobjects/dev.java.net

Not a single person open source project

FxObjects is developed and supported by

ObjectSource (http://www.objectsource.com)

Download, use, extend, redistribute, OEM

Discussion Forums on project site

We will answer your questions

Participation welcome

Post ideas, questions, concerns, comments

Contribute code