Language switching - l10n I18n - java

How does language switching work in Java/Vaadin? I have a web application and would like to integrate a combo box, that changes the language of every text in this application. Do i need to mark each text that should get translated manually and define its translation? How complex is it to implement this function into an exting project?

Do i need to mark each text that should get translated manually and define its translation?
You should use ResourceBundles to store/read translations of strings.
How does language switching work in Java/Vaadin?
You need to provide a class that implements I18NProvider. Documentation about that can be found here
Once implemented correctly, you will be able to call getTranslation("HelloWorld") on any Component (and therefore on any view since they must extend a component), to receive the translation of the key "HelloWorld" defined in the ResourceBundle-file of the current UI-Locale.
Views that extend LocaleChangeObserver are notified when the Locale is changed, and then you can call getTranslation("HelloWorld") again to find the translation of the freshly set language.
I would like to integrate a combo box, that changes the language of every text in this application.
See this SO answer of mine where I posted example code of a Select component that acts as a language switcher. It is using both ResourceBundle and I18NProvider. (You can use a ComboBox too, but with the downside that you can only display a String for the selected value)
The important part in that code there is that the Select has a ValueChangeListener that sets the Locale of the VaadinSession, which in turn will trigger the localeChange method of the LocaleChangeObserver that your view now should implement. In the localeChange method, you can re-translate the translatable Strings of every component in the view; set new texts in Labels, set new labels and placeholders for TextFields, etc etc.
How complex is it to implement this function into an exting project?
That depends very much on your definition of complex, and how familiar you already are with ResourceBundles. There certainly are less complex topics than this, but I18N is never easy. In my opinion, Vaadin has done a very great job of providing us devs with a way to use I18N in our applications.

Most people use a sort of translation file system for their localization. Basically you make a text file for each language with a key and value system where you name every translated message with a key and a translated value. You can then use these keys (that should be predefined) to get the correct message for the language you want. These files can be anything really, but if you're looking for a simple java implementation then there are pretty simple ways to do it. For an example look here.

Did you look at this section of the documentation? https://vaadin.com/docs/v14/flow/advanced/tutorial-i18n-localization.html

Related

assign data from dto to group of text fields in javafx

I'm new to JavaFX and what I'm trying to do is I have a DTO object with 15 fields that I fetch from backend which I need to show all the fields in screen
for now what I did for each filed will create textfield in fxml file and inject it in the controller using textfield id then set the text for that from the dto for example
#FXML
TextField firstName;
........
firstName.setText(dto.getFirstName)
so is there is any other way than going through each textfield and using setText to set their value
As you state that you are new to JavaFX, I do not recommend that you try to implement the potential approaches in this answer.
Investigate the controlsfx BeanPropertyUtils, PropertySheet and PropertyEditor.
Different potential implementation strategies:
You could use a collection of TextFields, e.g. a list and assign values sequentially based on, for example, position in an sql row set.
Or perform a lookup on a map of strings to TextFields based on a column name key.
Or use reflection on Java Beans (this is how controlsfx works).
But none of them would be worth implementing unless you have a great many fields and need some generic system to handle values. Otherwise I wouldn’t recommend implementing such abstract functionality.
An example of a generic use case would be if you were introspecting on an unknown large database schema.
If you do need to do this, probably your best place to start would be the controlsfx library.
SceneBuilderKit, which was used to build SceneBuilder, has similar functionality but it is not as easily accesible as ControlsFX.
I advise you review the above comments then decide if you really want to do this.
If you do, then choose one potential strategy and implement it (this won’t be done in a StackOverflow answer).
If stuck, provide a complete minimal reproducible example for a concrete example and implementation attempt in code, only for the art of the problem you are stuck on. This allows you to create a more concrete question that is greatly reduced in scope.

Xpages "Views" with beans: Categorize, Sort, Search

I'm trying to do the OOP approach in all my xPages. As expected I'm facing several issues, but also have tons of advantages doing so.
My question is related to Views (Repeat controls). I am loading a List<myCustomBean> for my repeat controls that contains all available objects of type myCustomBean and display each myCustomBean the way I want in a Bootstrap table row. That works all fine.
I'm able to sort my List with URL parameter sortedBy=MySortColumn with my own method. - Problem 1 solved.
How would I approach a Categorization in my Repeat Control? So I could easily sort the beans by the Cotegory, but how would I display it, incl. expandable and collapsible twisties? Maybe there is a Custom control that I can use? Or a Control of the Extension Library?
Or do I have to build everything from scratch myself?
Any advice is much appreciated.
The Data View control is probably the best. Like the View Panel or Data View, it's a extension of the Repeat Control. But it has much more flexibility that the View Panel and allows much more configurable layout than the Data View. It has a categoryColumn property, but that's designed for binding to a dominoView datasource. But there is also the categoryRow facet which can be used.
Essentially, using a dominoView component is already using OOP programming. Your repeat is using List<myCustomBean>, dominoView returns List<DominoViewEntry>. Properties on the dominoView are used to interrogate the underlying View object within the database and return only those ViewEntry objects from the ViewNavigator or ViewEntryCollection that are required. It wraps the ViewEntry as a DominoViewEntry object for just a selection of those, based on the rows property of whatever uses the DominoView.
As someone who built a subset of that functionality for use from Vaadin (see my XPages to Web App blog series http://www.intec.co.uk/tag/xpages-to-web-app-tutorial/), within XPages I typipcally use the dominoView object unless I'm extracting a small subset of ViewEntries / Documents. When I use ViewEntryCollection / DocumentCollection, I rarely wrap, preferring to let XPages optimise retrieval rather than re-develop that optimisation myself.

How can I generate and compile Java files in Android at Runtime

I know with javax.tools.* it is possible, but since this is not included in the Android API, I'm desperately wondering, is this possible?
Right now, my goal is to create a drag-and-drop tool to allow users to create their own layouts (as not everyone wants to learn Mobile Development, as it requires a lot of time, dedication and practice) similar to how Android Studio does it's own. However, of course the most important thing is to implement functionality via onClickListener and onTouchListeners. I've begun remedying this by creating my own DSL (Domain-Specific-Language) with a GUI front-end allowing users to choose what they want via PopupMenu and SubMenus. For example...
Statements
{ if, for, while }
Statements must be followed immediately by a reference and then a conditional (obtained from that reference), like a "if(Object.conditional())" statement.
References
{ Object1, Object2, Object3 }
The objects are references to other Views (I.E, Buttons, Layouts, WebView, etc.).
Conditionals|Actions|Getters|Setters
{ isSomething(), doSomething(), getSomething(), setSomething() }
Each Reference's methods, wrapped so that each wrapper keeps track of it's method's attributes and description (hence documentation).
It would go something like such...
IF ImageView1.isVisible()
ImageView1.setVisible(false)
ELSE
ImageView1.setVisible(true)
Of course, the method setVisible(boolean) is a wrapped version of setVisiblity(int).None of this is typed, it is obtained from a simple PopupMenu which shows them the applicable selections based on current context.
How I plan on transcribing this to compiling code was to convert the statement into Java code, inserting references on the fly as they are needed (I.E, ImageView1 would be defined in java as private ImageView ImageView1;), generate methods somewhat similar to how ButterKnife generates it's extra classes for it's onClick and onTouch annotations, etc.
Then, after planning all of this (been working on it for 2 weeks now), I find out that Android does not have support for compiling code like this. Please tell me something like this is possible. It's something I 100% wanted to do. Is this possible with any third party libraries?
If not, is there some possible way to mimic doing so? I could do it the long and slow way, of preparing every such possible way, keeping track of the references myself through a map, and when it is about to be called, directly call the implemented method for the View associated with that key, which theoretically COULD work. In fact, that'd be my second go-to if I can't. It'd be messy though.
Sorry if this is too long, I just want to get this to work.
TL;DR: Is there a way to compile a generated Java file created at Runtime in Android (since javax.tools.* does not exist), and if not what would be the best way to do so?

Something similar to GenericDialog/ADM

I'm looking for something similar to GenericDialog used in ImageJ or Adobe Dialog Manager. The goal is to create a template of a dialog (number of fields, types etc - info that is needed, not how it is presented) and send it to view-class. This view may be Swing based GUI or simple console UI. User fills the fields and values are visible for the source of the dialog template.
Is there some library for Java that implements this?
I know there is GenericDialog, but I'm not sure if I can use it in my project (as it is a part of ImageJ). What is more, I feel it's to 'heavy' for me.
The ImageJ2 project provides almost exactly what you describe: a flexible mechanism for executing runnable operations (called commands) with typed input and output parameters.
You define the command's inputs and outputs by labeling them with the #Parameter annotation. ImageJ automatically takes care of filling in the inputs (typically by prompting the user for input using a dialog box), as well as displaying the outputs after the command has run.
How the inputs are harvested from the user depends on which (if any) user interface is associated with the ImageJ context. We have implemented full widget support for Swing, as well as proof-of-concept implementations in "pure" AWT (i.e., java.awt widgets), Apache Pivot and Eclipse SWT.
Some examples:
GradientImage.java: A simple example command
ParameterTester.java: A command exercising many types of parameters
All of the code is BSD-2 licensed. The ij-core JAR containing the framework is ~334KB as of this writing. The ij-ui-swing JAR containing the Swing widgets is ~150KB, but it contains other things as well which could be stripped out (for comparison, the ij-ui-pivot JAR is only ~30KB).
All of that said, if you think ImageJ 1.x's GenericDialog is "too heavy" then you will very likely feel the same about ImageJ2's command framework (or really any other solution to this problem; I don't think it can get much "lighter" than GenericDialog). But in that case, perhaps the ImageJ2 implementation will give you some ideas on how to roll your own.
Generic dialog in ImageJ extends java.awt.Component so doesn't this contradict your requirement that the template for the dialog be decoupled from the view?
Java's collections would allow you to encapsulate the info, types etc.
java.util.LinkedHashMap<String,Type> dialog = new java.util.LinkedHashMap<String,Type>;
where the key is the name of the field and the value is the type of the field.
To create a swing based dialog see
http://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

Correct way to use Actions to create menus, toolbars, and other components in Java

The naive way of writing building a menu in a Java Swing app is to do something like:
JMenu fileMenu = new JMenu("File");
JMenuItem openItem = new JMenuItem("Open...");
openItem.addActionListener(new ActionListener() { /* action listener stuff */ } )
fileMenu.addMenuItem(openItem);
A more experienced developer will recognize that actions can be accessed through a variety of mechanisms - menus, toolbar buttons, maybe even other workflows in the system. That person is more likely to write:
Action openAction = new AbstractAction();
openAction.setName("Open...");
openAction.addActionListener(new ActionListener() { /* action listener stuff */ } )
...
JMenuItem openItem = new JMenuItem(openAction);
My question is, what is the best way to manage these Action objects so they can be used across menus, toolbars, etc?
Create a factory class that returns specific actions?
Declare all of the actions as private static final Action in some utility class?
Take advantage of a Java application framework?
Something else?
Applications that I have developed that need to use that same actions across menus, toolbars, and other buttons have been done using Swing Application Framework.
Swing Application Framework
This framework will allow you to have a resource file where you can define all menu text, tooltips, and ICONS. I think the icons are the key, you do not have to load them yourself. Also, if you have any actions that you need to enable/disable you can override the method to control its state.
The website is worth the read.
You can group all your abstractAction using the dedicated Map javax.swing.actionmap .
See http://java.sun.com/javase/6/docs/api/javax/swing/ActionMap.html
Moreover each JComponent has an internal actionMap (getActionMap()).
class MyComponent
extends JPanel
{
public static final String ACTION_NAME1="my.action.1";
public MyComponent()
{
AbstractAction action= new AbstractAction() { ... }
getActionMap().put(ACTION_NAME1,action);
...
menu.add(getActionMap().get(ACTION_NAME1));
}
}
Hope it helps
Action is a bad abstraction - an ActionListener welded to a poor man's Map.
Certainly do not assign them to a static as they are mutable and also need some context to operate usefully.
My general advice for GUI programming is to note that it is actually much the same as any other area of programming. Follow the usual good practices. Notably, layering, separation of concerns, use (implementation) inheritance rarely and don't write a big ball of mud.
Also see this question, which is pretty much the same as what you're asking.
Create a base action for your application; this will help you IMMENSELY later on
Do create actions as you have in your code, instead favor subclasses of your base action
To organize them, it will depend on what you are doing with them, and you may have some actions organized one way and others created a different way. It will all depend.
What you want is to have a consistent way to locate/create an action in your code.
Depending on your UI, you may need to differentiate between "static" actions (i.e. stuff that's always available in your app, such as the menu system) and dynamic actions that are created only on certain screens or in certain locations.
In any case, using concrete subclasses of your specialized base action will help you keep these things organized. What you don't want is to be specifying things like labels, mnemonics, and icons all over the place in your code.
Edit: I got the feeling people didn't believe this was possible or easy, so I did it--took about an hour from scratch--would have taken 40 mins if I'd just used a single method as a target instead of reflecting it out to separate methods for each menu item.
Here's the Tested source code. It works, but is one big method and ugly--refactor it if you use it. I may fix it up a little over the next few days, I've always wanted to have a copy of this to keep around to reuse.
--- original post
First of all, remember to separate your code from data. That means you should NEVER type:
new Menu("File...");
The string "File..." is data. If you start thinking this way, you will find that your question answers itself.
First you need to build up some data. You need to get "File..." and "Save" into menus. I generally start off with a string array (which you can easily move to a file)
new String[]{"File...","+Save","Load"...}
This is one of the simpler patterns I've started out with. Then you can parse out the + sign and use it to mean "Drop down a level in the menu when you add this one"
This is just a silly convention, invent your own if you don't like it.
The next step is binding that to code to run. You could have them all call the same method, but what a pain in the ass (Giant switch statement). One possibility is to use reflection to bind a method name while you are reading in the data. Here's one solution (again it might not fit your tastes)
new String[]{"File...[fileMenu]","+Save[saveMenu]","Load[loadMenu]"...}
Then you parse out the thing in square braces, reflectively hook it up to a method in your current class and you are set.
There is a temptation I ALWAYS have at this point, and I've learned to fight it because it NEVER works out. The temptation is to use the first set of data ("File...") and manipulate it to fit some pattern and auomatically bind to your code (in this case, remove all non-alpha chars, make the first letter lower case and append "Menu" to get the correct method name). Feel free to try this, it's very attractive and seems slick, but be ready to abandon it when it doesn't meet some need (such as two menu items with the exact same name in different sub-menus).
Another way would be if your language supports closures, then you could actually create the file name and closure in the same place..
Anyway, once you start coding like this, you'll find that ALL your menu construction is in a single 10 line method and you can alter it to suit your needs. I had a case where I had to change a set of menus to a button hierarchy and I did it in 2 minutes.
In the end, you can use this pattern to set up the action objects easily and change how they are used easily (in a single location, single line of code), so you experiment with them. There are many ways to use them, but if you don't do what I'm recommending here, you will end up having to re-implement across every menu item for every change, which is really annoying--after a single change you will have wasted more time than if you had just implemented a data-driven solution in the first place.
This really isn't hard code, should take like an hour or two then you never have to write new Menu("... again. Trust me, this kind of tooling is just about always worth it.
edit:
I just about always code data-driven these days. Usually I'll prototype a few things the normal way, recognize the pattern and refactor--and if you are refactoring correctly, the data just about always factors out and what you're left with is beautiful, tight and maintainable.
I could do what I suggested above in less than 1/2 an hour (maybe an hour to do the reflective version). This is almost always just as long as it would do to use the unfactored version, and from then on, your savings multiply for every change.
This is very similar to what people like about ruby, except with ruby they seem to insert even more data into their code (which makes it awfully hard to extract your data from the code completely, which is always a nice goal for internationalization).
Hmm, did I mention that if you're good at extracting your data like this, i18n is virtually free?
I suggest you just give it a try sometime and see what you think. Embedding the control in the strings is unnecessary if it makes you uncomfortable. I tend to use string/object arrays just because they are really easy to enter, are still in the file while you are coding and are trivial to externalize later, but if you like YML or XML or properties files, use whatever you're comfortable with--just abstract your data from your code!

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