JavaFX Dependency Injection with FxContainer

JavaFX Dependency Injection with FxContainer Presented by Srikanth Shenoy ObjectSource Learn FxContainer in 10 minutes

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 Injection FXLocal.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); //initialize the variable. Basis for FxContainer Init Injection objValue.initVar(varMember, varValue); objValue.initialize(); //Finally initialize the object

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"/> <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> </fxcontainer>

FxContainer: Import Properties  Good for Spring style ${ } substitutions <fxcontainer> <import resource="/org/fxobjects/samples/abc.properties"/> <fxobject name="movieFinder" class="org.fxobjects.samples.fxcontainer.MovieFinderImpl"> <property name="someVar" value=“${svr1Name} is ${svr1Status}"/> <property name="javaHelper" ref=“${helperObj}"/> <property name="jfxHelper" ref="jfxHelperVarObj"/> </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> <fxobject name="movieFinder" class="org.fxobjects.samples.fxcontainer.MovieFinderImpl“ lazy- init=“false” load-order=“1” init-method=“someMethod”> .. </fxobject> </fxcontainer>

FxContainer: Sequences <fxcontainer> <fxobject name="movieFinder" class="org.fxobjects.samples.fxcontainer.MovieFinderImpl"> <property name="movieCodes">  Primitive Sequence <sequence> <entry value=“1" /> <entry value="2" /> </sequence> </property> <property name="movies">  Object Sequence <sequence> <entry ref="movie1"/> <entry ref="movie2"/> </sequence> </property> </fxobject> </fxcontainer>

FxContainer: Lists and Sets <fxcontainer> <fxobject name="movieFinder" class="org.fxobjects.samples.fxcontainer.MovieFinderImpl"> <property name="movieList">  Object LIST <list> (or <set>) <entry ref="movie1"/> <entry ref="movie2"/> </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> <fxobject name="movieFinder" class="org.fxobjects.samples.fxcontainer.MovieFinderImpl"> <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

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

JavaFX Dependency Injection with FxContainer

by Srikanth Shenoy

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JavaFX Dependency Injection with FxContainer Presentation Transcript