javafx dependency injection with fxcontainer

JavaFX Dependency

Injection with

FxContainer

Presented by

Srikanth Shenoy

ObjectSource

Learn FxContainer in 10 minutes

http://www.objectsource.com/

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 and FxContainer framework

Introduction

What is FxContainer? (Currently 1.0)

Open source IoC container written in JavaFX.

Meant specifically for Dependency Injection in

JavaFX applications

Very much Spring-like

Small footprint (< 75K)

Sequence, Collection Support

Mix Java and JavaFX wiring

Learn FxContainer in 20 slides! (10 minutes)

IoC Container Landscape

Spring

Supports XML and Annotations based DI

Supports Constructor & Setter Injection

Guice

Supports Annotations and API based DI

Supports Constructor & Setter Injection

PicoContainer and many more..

Why another IoC Container?

Problems with existing IoC Containers (in the

context of JavaFX)

JavaFX does not support annotations

Hence Guice leaves only programmatic DI option

Xml DI with Spring works, but minimal jars > 1 MB

Constructor Injection not supported in JavaFX

Setter Injection is unnatural for JavaFX style

JavaFX variables are written as public or public-init

Writing setXYZ() method for variables feels artificial

Nobody supports Sequence (the first class

JavaFX collection citizen)

Setter Injection

var finder = MovieFinder {

movieDao: MovieDao { }

}

Dependency Injection with any other IoC

container needs a setter like this (Not Good)public class MovieFinder {

public-init movieDao:MovieDao;

public function setMovieDao(dao:MovieDao) {

this.movieDao = dao;

}

}

Side effects of Setter Injection

Init and Post-Init code that depends on

public-init variables will not work

Classic Example – CustomNode.create()

Called automatically in every UI

Called immediately after init and post init

No time to call setter methods

If create() depends on objects injected by setter

injection, then it will fail !!

A Different Kind of Injection

Constructor Injection is DURING memory

allocation

Setter Injection is AFTER memory allocation

and object initialization

JavaFX needs something in between the two

We call it Init injection

A DI based on Init Injection does not exist

So we created it

FxContainer is the ONLY IoC container that

provides Init Injection for JavaFX

FxContainer Core Concept

Based on JavaFX Reflection and Init InjectionFXLocal.Context ctx = FXLocal.getContext();

//get the class

FXClassType clzType = ctx.findClass("org.fxobjects.MovieFinder");

FXObjectValue objValue = clzType.allocate(); //allocate memory

//get the variable-type

FXVarMember varMember = clzType.getVariable("movieDao");

//create the variable-value

FXValue varValue = ctx.mirrorOf(Some String or object);

objValue.initialize(); //Finally initialize the object

//initialize the variable. Basis for FxContainer Init Injection

objValue.initVar(varMember, varValue);

FxContainer Overview

Uses Setter Injection for Java objects

Uses Init Injection for JavaFX objects

Can mix both Java and JavaFX objects

Java objects can hold references to JavaFX

objects via interfaces

Very Spring Like in configuration

Powerful, Lightweight and Easy to use

FxContainer: Simple

Dependency Injection

<fxcontainer>

<fxobject name="movieFinder"

class="org.fxobjects.samples.fxcontainer.MovieFinderImpl">

<property name="someVar" value="Some random value"/>

<property name="javaHelper" ref="javaHelperObj"/>

<property name="jfxHelper" ref="jfxHelperVarObj"/>

</fxobject>

<fxobject name="movieLister"

class="org.fxobjects.samples.fxcontainer.MovieLister">

<property name="finder" ref="movieFinder"/>

</fxobject>

</fxcontainer>

FxContainer: Import XML

Good for organizing large XML into smaller

logical chunks<fxcontainer>

<import resource="/org/fxobjects/samples/abc.xml"/>



<property name="someVar" value="Some random value"/>

<property name="javaHelper" ref="javaHelperObj"/>


</fxobject>

</fxcontainer>

FxContainer: Import Properties

Good for Spring style ${ } substitutions <fxcontainer>

<import resource="/org/fxobjects/samples/abc.properties"/>



<property name="someVar" value=“${svr1Name} is ${svr1Status}"/>

<property name="javaHelper" ref=“${helperObj}"/>


</fxobject>

</fxcontainer>

value and ref can be substituted

FxContainer: Wired Object

Attributes

Wired Objects in FxContainer have the following defaults

(can be overridden)

Every wired object is singleton

Every wired object is lazily initialized (i.e on demand)

There is no order of initialization (Although load order can be

specified for eagerly loaded objects)

Init-method is called after all properties are injected<fxcontainer>


class="org.fxobjects.samples.fxcontainer.MovieFinderImpl“ lazy-

init=“false” load-order=“1” init-method=“someMethod”>

..

</fxobject>

</fxcontainer>

FxContainer: Sequences

<fxcontainer>



<property name="movieCodes"> Primitive Sequence

<sequence>

<entry value=“1" />

<entry value="2" />

</sequence>

</property>

<property name="movies"> Object Sequence

<sequence>

<entry ref="movie1"/>


</sequence>

</property>

</fxobject>

</fxcontainer>

FxContainer: Lists and Sets

<fxcontainer>



<property name="movieList"> Object LIST

<list> (or <set>)



</list>

</property>

<property name="movieCodes"> Primitive LIST

<list valueClass=“java.lang.Integer”>

<entry value=“1" />

<entry value="2" />

</list>

</property>

</fxobject>

</fxcontainer>

FxObjects Lists and Sets

(Contd.)

Lists and Sets have to be initialized in their

parents with a new …..();

valueClass attribute

Optional in most cases

Reason: One cannot tell from the xml value

attributed if a list is Integer, String, BigDecimal

etc.

Needed for Java and JavaFX objects when

value attribute is specified in xml AND

List is not parameterized (always the case in JavaFX)

FxContainer: Maps

<fxcontainer>



<property name="movieMap"> Object MAP

<map>

<entry keyRef=“stage1” valueRef="movie1"/>

</map>

</property>

<property name="movieCodes"> Primitive MAP

<map keyClass=“java.lang.String”

valueClass=“java.lang.Integer”>

<entry key=“Terminator 1” value=“1" />

<entry value=“Terminator 2" />

</map>

</property>

</fxobject>

</fxcontainer>

keyClass and valueClass are needed for Maps in JavaFX with key

and value specified. (since they cannot be parameterized) and

non-parameterized Maps in Java

FxContainer: Startup

Spring Like var loader = ClasspathXmlContainerLoader {

resourceLocation: "/org/fxobjects/samples/my.xml“

}

var container:FxContainer = loader.load();

var mvLister:MovieLister =

container.getFxObject("movieLister") as MovieLister;

FxContainer can be used the IoC container

with FxObjects or any other JavaFX

application independently

Just include 2 jars – fxcontainer.jar and

fxobjects-util.jar in classpath

FxObjects & FxContainer:

Roadmap

Links

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

FxContainer is a subproject of FxObjects

Not a single person open source project

FxObjects and FxContainer developed and supported

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

Download, use, extend, redistribute, OEM

Discussion Forums on project site

Participation welcome

Post ideas, questions, concerns, comments

Contribute code

https://fxobjects/dev.java.net

http://www.objectsource.com/

javafx dependency injection with fxcontainer

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