I have a JavaFX application where I would like to introduce Guice because my Code
is full of factorys right now, only for the purpose of testing.
I have one use case where i have a controller class of a certain view.
This controller class has a viewmodel and I pass the model to the viewmodel via
the constructor of the controller class.
In the controller class I have a contactservice object that provides the edit/save/delete operations.
As of now I have an interface of that object and provide an implementation and a Mock. This object can be retrieved by a Factory.getInstance() method.
What I want to do is something like this:
public class NewContactController implements Initializable {
// ------------------------------------------------------------------------
// to inject by guice
// ------------------------------------------------------------------------
private ContactService contactService;
#Inject
public void setContactService(ContactService srv) {
this.contactService = srv;
}
// edit window
public NewContactController(Contact c) {
this.viewModel = new NewContactViewModel(c);
}
// new window
public NewContactController() {
this.viewModel = new NewContactViewModel();
}
#FXML
void onSave(ActionEvent event) {
//do work like edit a contcat,
contactService.editContact(viewModel.getModelToSave());
}
#Override
public void initialize(URL location, ResourceBundle resources) {
// bind to viewmodel---------------------------------------------------
}
}
How can I achive this? Is it a good a idea to do something like that?
While I was searching for a solution I found fx-guice and similar frameworks but how can i combine these two?
Specially how can I let this fields be injected AND instanciate the controller myself or at least give it some constructor args?
I don't use Guice, but the simplest approach would appear to be just to use a controller factory on the FXMLLoader. You can create a controller factory that instructs the FXMLLoader to use Guice to initialize your controllers:
final Injector injector = Guice.createInjector(...);
FXMLLoader loader = new FXMLLoader(getClass().getResource(...));
loader.setControllerFactory(new Callback<Class<?>, Object>() {
#Override
public Object call(Class<?> type) {
return injector.getInstance(type);
}
});
// In Java 8, replace the above with
// loader.setControllerFactory(injector::getInstance);
Parent root = loader.<Parent>load();
There's a good DI framework for javaFX called afterburner.fx. Check it out, I think it's the tool you're looking for.
Assuming you (could) instantiate the controller by hand/guice and not from the FXML, you could use https://github.com/google/guice/wiki/AssistedInject if you need to pass any non DIable parameter to the constructor. You would then set the controller manually to the FXMLLoader with .setController(this) and load the FXML file in the constructor of the controller.
Not sure if there are any drawbacks, but this kind of system seems to work for me :)
To use JavaFx with Guice :
Extend javafx.application.Application & call launch method on that class from the main method. This is the application’s entry point.
Instantiate dependency injection container of your choice. E.g. Google Guice or Weld.
In application’s start method, instantiate FXMLLoader and set it’s controller factory to obtain controllers from the container. Ideally obtain the FXMLLoader from the container itself, using a provider. Then give it an .fxml file resource. This will create content of the newly created window.
Give the Parent object instantiated in previous step to Stage object (usually called primaryStage) supplies as an argument to the start(Stage primaryStage) method.
Display the primaryStage by calling it’s show() method.
Code Example MyApp.java
public class MyApp extends Application {
#Override
public void start(Stage primaryStage) throws IOException {
Injector injector = Guice.createInjector(new GuiceModule());
//The FXMLLoader is instantiated the way Google Guice offers - the FXMLLoader instance
// is built in a separated Provider<FXMLLoader> called FXMLLoaderProvider.
FXMLLoader fxmlLoader = injector.getInstance(FXMLLoader.class);
try (InputStream fxmlInputStream = ClassLoader.getSystemResourceAsStream("fxml\\login.fxml")) {
Parent parent = fxmlLoader.load(fxmlInputStream);
primaryStage.setScene(new Scene(parent));
primaryStage.setTitle("Access mini Stock App v1.1");
primaryStage.show();
primaryStage.setOnCloseRequest(e -> {
System.exit(0);
});
} catch (IOException ex) {
ex.printStackTrace();
}
}
public static void main(String[] args) {
launch();
}
}
Then FXMLLoaderProvider.java
public class FXMLLoaderProvider implements Provider<FXMLLoader> {
#Inject Injector injector;
#Override
public FXMLLoader get() {
FXMLLoader loader = new FXMLLoader();
loader.setControllerFactory(p -> {
return injector.getInstance(p);
});
return loader;
}
}
Thanks to mr. Pavel Pscheidl who provided us with this smart code at Integrating JavaFX 8 with Guice
Related
I want to set some non-UI fields in the controller before the initialize method of the controller gets called automatically upon creation. As I understand it, the way to do it is to provide custom ControllerFactory, since initialize() gets called after ControllerFactory returns the created object. I wanted to use the following code as per this answer:
FXMLLoader loader = new FXMLLoader(mainFXML); // some .fxml file to load
loader.setControllerFactory(param -> {
Object controller = null;
try {
controller = ReflectUtil.newInstance(param); // this is default behaviour
} catch (InstantiationException | IllegalAccessException e) {
e.printStackTrace();
}
if (controller instanceof Swappable) {
((Swappable) controller).setSwapper(swapper); // this is what I want to add
}
return controller;
});
However, the ReflectUtil class (which is used in default setControllerFactory method) is part of com.sun.reflect.misc package, which I am not able to use, since compiling fails with error: package sun.reflect.misc does not exist.
As I understand it, I can't use sun packages, since this is not public API. So the question is: what do I do? I can't find any other examples of this, only the ones with ReflectUtil and, well, I want my ControllerFactory to comply with default workflow of JavaFX with #FXML annotations and all that, is this possible with some other DI framework like Jodd Petite, for example? Is there some other way to set the field? (other than to synchronize on it and wait in initialize() until the setter method gets called from other thread).
Full code on github for context.
If you want to create an instance via reflection then you need to use Class.getConstructor(Class...)1 followed by Constructor.newInstance(Object...).
FXMLLoader loader = new FXMLLoader(/* some location */);
loader.setControllerFactory(param -> {
Object controller;
try {
controller = param.getConstructor().newInstance();
} catch (ReflectiveOperationException ex) {
throw new RuntimeException(ex);
}
if (controller instanceof Swappable) {
((Swappable) controller).setSwapper(swapper);
}
return controller;
}
This code requires that your controller class has a public, no-argument constructor. If you want to inject your dependencies through the constructor you could do something like:
FXMLLoader loader = new FXMLLoader(/* some location */);
loader.setControllerFactory(param -> {
Object controller;
try {
if (Swappable.class.isAssignableFrom(param)) {
controller = param.getConstructor(Swapper.class).newInstance(swapper);
} else {
controller = param.getConstructor().newInstance();
}
} catch (ReflectiveOperationException ex) {
throw new RuntimeException(ex);
}
return controller;
}
This code assumes that all subclasses of Swappable have a public, single-argument constructor that takes a Swapper.
If you want to get a non-public constructor you'll need to use Constructor.getDeclaredConstructor(Class...). Then you'd need to call setAccessible(true) on the Constructor before invoking it.
Couple things to remember if using Jigsaw modules (Java 9+) and this controller factory code is not in the same module as the controller class. Let's say the controller factory code is in module foo and the controller class is in module bar:
If using a public controller with a public constructor then bar must exports the controller class' package to at least foo
If using a non-public controller and/or constructor then the same thing must happen but with opens instead of exports
Otherwise an exception will be thrown.
1. If using a no-argument (not necessarily public) constructor you can bypass getConstructor and call Class.newInstance() directly. However, please note that this method has issues and has be deprecated since Java 9.
Personally, using reflection for my own code is a sign of bad design.
Here's a suggestion that uses FXML mechanisms to inject a user instance of an object. For this purpose, an object is created that describes the context in which the application works. Object user entities are registered in this object. This imposes some constraint on users not to implement a direct interface but to inherit an abstract class that will implement the logic of registering the instance in the context.
public interface Swapper {
}
public abstract class AbstractSwapper implements Swapper {
public AbstractSwapper() {
ApplicationContext.getInstance().setSwapper(this);
}
}
public class ApplicationContext {
private static ApplicationContext instance;
private Swapper swapper;
private ApplicationContext() {
}
public synchronized static ApplicationContext getInstance() {
if(instance == null) {
instance = new ApplicationContext();
}
return instance;
}
public synchronized static Swapper swapperFactory() {
Swapper swapper = getInstance().getSwapper();
if(swapper == null) {
swapper = new AbstractSwapper() {
};
getInstance().setSwapper(swapper);
}
return swapper;
}
public Swapper getSwapper() {
return swapper;
}
public void setSwapper(Swapper swapper) {
this.swapper = swapper;
}
}
In this case, the FXML file can be used fx:factory to use the swapper instance registered in ApplicationContext. Thus, FXMLLoader will inject the instance directly into the controller.
<GridPane fx:controller="sample.Controller" xmlns:fx="http://javafx.com/fxml" >
<fx:define>
<ApplicationContext fx:factory="swapperFactory" fx:id="swapper"/>
</fx:define>
</GridPane>
and sample.Controller
public class Controller {
#FXML
private Swapper swapper;
}
Another solution is for the controller to initialize the fields using the ApplicationContext directly. So the swapper field does not bind to the FXML file.
public class Controller {
private Swapper swapper;
#FXML
private void initialize() {
swapper = ApplicationContext.swapperFactory();
}
}
In both versions, the user simply has to create an instance of AbstractSwapper before using FXMLLoader.
public class Main extends Application {
#Override
public void start(Stage primaryStage) throws Exception{
AbstractSwapper s = new AbstractSwapper() {
};
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
Also, there is an option to use FXMLLoader to inject the object. In this case it goes through fx:reference or through fx:copy (if you have copy constructor)
My Application class looks like this:
public class Test extends Application {
private static Logger logger = LogManager.getRootLogger();
#Override
public void start(Stage primaryStage) throws Exception {
String resourcePath = "/resources/fxml/MainView.fxml";
URL location = getClass().getResource(resourcePath);
FXMLLoader fxmlLoader = new FXMLLoader(location);
Scene scene = new Scene(fxmlLoader.load(), 500, 500);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
The FXMLLoader creates an instance of the corresponding controller (given in the FXML file via fx:controller) by invoking first the default constructor and then the initialize method:
public class MainViewController {
public MainViewController() {
System.out.println("first");
}
#FXML
public void initialize() {
System.out.println("second");
}
}
The output is:
first
second
So, why does the initialize method exist? What is the difference between using a constructor or the initialize method to initialize the controller required things?
Thanks for your suggestions!
In a few words: The constructor is called first, then any #FXML annotated fields are populated, then initialize() is called.
This means the constructor does not have access to #FXML fields referring to components defined in the .fxml file, while initialize() does have access to them.
Quoting from the Introduction to FXML:
[...] the controller can define an initialize() method, which will be called once on an implementing controller when the contents of its associated document have been completely loaded [...] This allows the implementing class to perform any necessary post-processing on the content.
The initialize method is called after all #FXML annotated members have been injected. Suppose you have a table view you want to populate with data:
class MyController {
#FXML
TableView<MyModel> tableView;
public MyController() {
tableView.getItems().addAll(getDataFromSource()); // results in NullPointerException, as tableView is null at this point.
}
#FXML
public void initialize() {
tableView.getItems().addAll(getDataFromSource()); // Perfectly Ok here, as FXMLLoader already populated all #FXML annotated members.
}
}
In Addition to the above answers, there probably should be noted that there is a legacy way to implement the initialization. There is an interface called Initializable from the fxml library.
import javafx.fxml.Initializable;
class MyController implements Initializable {
#FXML private TableView<MyModel> tableView;
#Override
public void initialize(URL location, ResourceBundle resources) {
tableView.getItems().addAll(getDataFromSource());
}
}
Parameters:
location - The location used to resolve relative paths for the root object, or null if the location is not known.
resources - The resources used to localize the root object, or null if the root object was not localized.
And the note of the docs why the simple way of using #FXML public void initialize() works:
NOTE This interface has been superseded by automatic injection of location and resources properties into the controller. FXMLLoader will now automatically call any suitably annotated no-arg initialize() method defined by the controller. It is recommended that the injection approach be used whenever possible.
My Application class looks like this:
public class Test extends Application {
private static Logger logger = LogManager.getRootLogger();
#Override
public void start(Stage primaryStage) throws Exception {
String resourcePath = "/resources/fxml/MainView.fxml";
URL location = getClass().getResource(resourcePath);
FXMLLoader fxmlLoader = new FXMLLoader(location);
Scene scene = new Scene(fxmlLoader.load(), 500, 500);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
The FXMLLoader creates an instance of the corresponding controller (given in the FXML file via fx:controller) by invoking first the default constructor and then the initialize method:
public class MainViewController {
public MainViewController() {
System.out.println("first");
}
#FXML
public void initialize() {
System.out.println("second");
}
}
The output is:
first
second
So, why does the initialize method exist? What is the difference between using a constructor or the initialize method to initialize the controller required things?
Thanks for your suggestions!
In a few words: The constructor is called first, then any #FXML annotated fields are populated, then initialize() is called.
This means the constructor does not have access to #FXML fields referring to components defined in the .fxml file, while initialize() does have access to them.
Quoting from the Introduction to FXML:
[...] the controller can define an initialize() method, which will be called once on an implementing controller when the contents of its associated document have been completely loaded [...] This allows the implementing class to perform any necessary post-processing on the content.
The initialize method is called after all #FXML annotated members have been injected. Suppose you have a table view you want to populate with data:
class MyController {
#FXML
TableView<MyModel> tableView;
public MyController() {
tableView.getItems().addAll(getDataFromSource()); // results in NullPointerException, as tableView is null at this point.
}
#FXML
public void initialize() {
tableView.getItems().addAll(getDataFromSource()); // Perfectly Ok here, as FXMLLoader already populated all #FXML annotated members.
}
}
In Addition to the above answers, there probably should be noted that there is a legacy way to implement the initialization. There is an interface called Initializable from the fxml library.
import javafx.fxml.Initializable;
class MyController implements Initializable {
#FXML private TableView<MyModel> tableView;
#Override
public void initialize(URL location, ResourceBundle resources) {
tableView.getItems().addAll(getDataFromSource());
}
}
Parameters:
location - The location used to resolve relative paths for the root object, or null if the location is not known.
resources - The resources used to localize the root object, or null if the root object was not localized.
And the note of the docs why the simple way of using #FXML public void initialize() works:
NOTE This interface has been superseded by automatic injection of location and resources properties into the controller. FXMLLoader will now automatically call any suitably annotated no-arg initialize() method defined by the controller. It is recommended that the injection approach be used whenever possible.
Today I added Guice to my Java FX Application. The main goal was to replace the singletons I had with Injection and break up dependencies.
So far everything worked fine, this is the code I have to start a new Scene:
public class App extends Application{
public static void main(String[] args){
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
final String LANGUAGE_BUNDLE = "myBundlePath";
final String FXML = "myFXMLPath";
try {
ResourceBundle resourceBundle = ResourceBundle.getBundle(LANGUAGE_BUNDLE, Locale.GERMAN, this.getClass().getClassLoader());
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource(FXML), resourceBundle, new JavaFXBuilderFactory(), getGuiceControllerFactory());
primaryStage.setScene(new Scene(fxmlLoader.load()));
primaryStage.show();
}catch (IOException ex) {
ex.printStackTrace();
}
}
private Callback<Class<?>, Object> getGuiceControllerFactory(){
Injector injector = Guice.createInjector(new GuiceModule());
return new Callback<Class<?>, Object>() {
#Override
public Object call(Class<?> clazz) {
return injector.getInstance(clazz);
}
};
}
}
My Guice Module looks like this:
public class GuiceModule extends AbstractModule {
#Override
protected void configure() {
bind(ITester.class).to(Tester.class);
bind(ISecondTest.class).to(SecondTest.class);
}
}
Please note that i substituted the paths for the ressource bundle and the fxml file as they would have revealed my identity. But loading and everything works, so this shouldn't be a problem ;)
Now the problem is, that I want to instantiate a new view with a button click in a different view. The second view should display a more detailed version of the data in view 1.
Everything that I need to pass to the second view is an Integer (or int), but I have absolutely no clue on how to do this.
I have the standard FX setup with:
View.fxml (with a reference to the ViewController)
ViewController.java
Model.java
ViewModel.java
The ViewController then binds to properties offered by the ViewModel.
I need the int to choose the correct model.
Everything I could find was about the Annotation #Named but as far as I can see, this wouldn't be usable to inject dynamic data.
Could you please give me a hint what this what I want to do is called?
Or long story short: How can I inject a variable, chosen by a different view, in a second ViewController, and leaving the rest in the standard FX-way?
Any help appreciated and thanks in advance!
Regards, Christian
After trying around a bit more, it seems like I found a solution by myself!
However, it "feels" ugly what I'm doing, so I'd like to have some confirmation ;)
First the theory: Guice supports "AssistedInject". This is, when a class can not be constructed by a default constructor. In order to be able to use AssistedInject, you have to download the extension (I downloaded the jar from maven repository).
What AssistedInject does for you is that it allows you to specify a factory which builds the variable for you. So here is what I have done:
First, create an interface for the class which you want to use later, in my case:
public interface IViewController {
}
Second, create an interface for the factory. Important: you do not have to implement the factory
public interface IControllerFactory {
ViewController create(#Assisted int myInt);
}
Third, add the constructor with the corresponding parameters to your class which you want to instantiate later, and let it implement the interface you created like so:
public class ViewController implements IViewController{
#AssistedInject
public ViewController(#Assisted int i){
final String LANGUAGE_BUNDLE = "languageBundle";
final String FXML = "View.fxml";
try{
ResourceBundle resourceBundle = ResourceBundle.getBundle(LANGUAGE_BUNDLE, Locale.GERMAN, this.getClass().getClassLoader());
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource(FXML), resourceBundle, new JavaFXBuilderFactory());
fxmlLoader.setController(this);
Stage second = new Stage();
second.setScene(new Scene(fxmlLoader.load()));
second.show();
}catch (IOException e){
e.printStackTrace();
}
System.out.println("ViewController constructor called with: " + i);
}
Here are a few things to note:
The annotation "#AssistedInject" for the method
The annotation "#Assisted" for the parameter which we want to supply externally
we set the controller for the loader manually (with fxmlLoader.setController(this);)
I had to remove the controller configuration in the fxml file, so no "fx:controller" in the fxml!
Next we need to add a variable into the class from where we want to instantiate the other class:
#Inject
IControllerFactory controllerFactory;
We can use it in the class like so:
controllerFactory.create(3)
Note: we call the method "create" which we never implemented in the ViewController class! Guice knows it has to call the constructor - magic
As last step, we need to add the connection to our context in our GuiceModule, like so:
#Override
protected void configure(){
install(new FactoryModuleBuilder()
.implement(IPagingDirectoryViewController.class, PagingDirectoryViewController.class)
.build(IPagingDirectoryControllerFactory.class));
}
Note I got the error: Cannot resolve method 'implement java.lang.Class<"The interface class">, java.lang.Class<"The implementing class">'. This was because I forgot to let my Controller class implement the interface.
Okay, so that's how I got it working.
As I said however, I'd be really happy about some opinions!
Regards, Christian
In your Module Configuration you could simply add a Provider Method for FXMLLoader, in which you assign Guices 'injector.getInstance()' as ControllerFactory for the loader.
#Provides
public FXMLLoader getFXMLLoader(com.google.inject.Injector injector) {
FXMLLoader loader = new FXMLLoader();
loader.setControllerFactory(injector::getInstance);
return loader;
}
All you have to do now, is to bind your ViewControllers in the configure() method of your module configuration.
// for example:
bind(ViewController.class);
And make sure the controller class is properly bound in your fxml file.
fx:controller="your.package.ViewController"
Now you simply use your injector to get an instance of FXMLLoader.
In JavaFX8 there is a UI Controls Architecture that is used for make custom controls. Basically is based in:
Control.
Skin.
CSS.
Also, there is a basic structure of an FXML project that is used to make GUI too. Basically:
Control.
FXML file.
CSS.
I would like to use FXML with the UI Controls Architecture, so my question is:
Who is the controller for the FXML file? The Skin?
I have to do something like this code below?:
public class MySkin extends SkinBase<MyControl> {
public GaugeSkin(MyControl control) {
super(control);
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("MyView.fxml"));
fxmlLoader.setRoot(control);
fxmlLoader.setController(control);
try {
fxmlLoader.load();
} catch (IOException exception) {
throw new RuntimeException(exception);
}
}
I think you're on the right track with the Skin class being the controller for the loaded FXML file because it is the Skin that is responsible for defining the nodes that comprise the 'look' of a particular control.
The Control class itself should really only define properties that hold the state of the control and should not care how the Skin actually creates the view hierarchy (that is, it should only care about it's state, not how it looks).
One difference I would make is to change fxmlloader.setController(control); to fxmlloader.setController(this); so that the Skin class becomes the controller rather than the control itself.
Another thing you could do is to move the FXMLLoader logic into a base class so that you don't have to duplicate it every time you want to create a Skin, something like this:
public abstract class FXMLSkin<C extends Control> extends SkinBase<C>{
public FXMLSkin(C control) {
super(control);
this.load();
}
private void load() {
FXMLLoader loader = new FXMLLoader(getFXML());
loader.setController(this);
try {
Node root = loader.load();
this.getChildren().add(root);
} catch (IOException ex) {
Logger.getLogger(FXMLSkin.class.getName()).log(Level.SEVERE, null, ex);
}
}
protected abstract URL getFXML();
}
I have a JavaFX UserControl on my Github page which does something very similar to the FXMLSkinBase class above. It uses a convention to load an FXML file with the same name as the derived class so that the FXML file name does not need to be specified each time. I.E. if your derived skin is called FooControlSkin, the control will automatically load an FXML file called FooControlSkin.fxml.
The class is very simple and the code could very easily be refactored into a fully featured FXMLSkinBase class that would meet your requirements.
My better way:
removing need for <fx:root> as root element of .fxml file.
removing need to call fxmlLoader.setRoot(control);.
removing need to call fxmlLoader.setController(control);.
allowing a Skin to be a controller automatically via fx:controller="{controller class name}" in FXML root element.
allowing an IDE to highlight bogus #FXML references to FXML in ControlNameSkin class.
A proper Control class.
public static class ControlName extends Control {
#Override
protected Skin<?> createDefaultSkin() {
ControlNameSkin.Factory factory = new ControlNameSkin.Factory(this);
FXMLLoader fxmlLoader = new FXMLLoader(getClass()
.getResource("ControlName.fxml"));
fxmlLoader.setControllerFactory(factory);
try {
Node root = fxmlLoader.load();
ControlNameSkin skin = fxmlLoader.getController();
skin.construct(root);
return skin;
} catch (IOException ex) {
throw new RuntimeException(ex);
}
}
}
A combined Skin and Controller class.
public static class ControlNameSkin extends SkinBase<ControlName> {
public ControlNameSkin(Factory factory) {
super(factory.control);
// any setup NOT using FXML references
}
public void construct(Node root) {
ControlName control = getSkinnable();
// any setup using FXML references
getChildren().add(root);
}
public static class Factory implements Callback<Class<?>, Object> {
public final ControlName control;
public Factory(ControlName control) {
this.control = control;
}
#Override
public Object call(Class<?> cls) {
try {
return cls.getConstructor(Factory.class).newInstance(this);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
}
}