Partial HTML generation from textile using eclipse Mylyn standalone

The title is pretty much explicit. For SlideshowFX, I needed to generate HTML content from textile, in order to define slide’s content. Looking for a lib, I found eclipse Mylyn that can be used in a standalone way. The library is pretty powerful but I have to look a lot at the sources in order to get the things done how I wanted to (#LukeAtTheSource power). Generally to convert a markup string into a HTML one, you create a MarkupLanguage as well as a MarkupParser and do the following:

final MarkupLanguage language = new TextileLanguage();
final MarkupParser parser = new MarkupParser(language);
parser.parseToHTML("h1. My little String");

The thing is that this code will create a whole HTML document (with html, head, body and so on tags). Me needs were to just get the HTML code corresponding to my string, e.g.

<h1>My little String</h1>

So the code should be changed to use a DocumentBuilder, like the following one:

final StringWriter writer = new StringWriter();
final DocumentBuilder builder = new HtmlDocumentBuilder(writer);
final MarkupLanguage language = new TextileLanguage();
final MarkupParser parser = new MarkupParser(language, builder);

// false indicates to not produce a whole HTML document
parser.parse("h1. My little String", false);

writer.flush();
writer.close();

String htmlContent = writer.toString();

This is almost done except that Mylyn generates IDs (which is kind of normal right?) by using the content of the markup. In short, I wanted to avoid IDs’ generation but I could’t find a right and efficient way to do it. So I decided to ensure uniqueness of IDs by always getting the current timestamp. Maybe it’s not a wonderful solution, but for the purpose of this little tutorial it will be perfect. The main idea is to change the ID generation and for doing this, you have to override some classes, because the default ID generation strategy is stored as a static and final variable, and no setters are available. The following example demonstrates how to do it:

final StringWriter writer = new StringWriter();

// The generation strategy generates IDs using the current timestamp
final IdGenerationStrategy idGenerationStrategy = new IdGenerationStrategy() {
  @Override
  public String generateId(String s) {
    return System.currentTimeMillis() + "";
  }
};

final IdGenerator idGenerator = new IdGenerator();
idGenerator.setGenerationStrategy(idGenerationStrategy);

final TextileContentState contentState = new TextileContentState() {
  @Override
  public IdGenerator getIdGenerator() {
    return idGenerator;
  }
};

// Override the language to return the created contentState used for the ID generation
final MarkupLanguage language = new TextileLanguage() {
  @Override
  protected ContentState createState() {
    return contentState;
  }
};

final DocumentBuilder builder = new HtmlDocumentBuilder(writer);

final MarkupParser parser = new MarkupParser(language, builder);

parser.parse(markupString, false);

writer.flush();
writer.close();

final String htmlContent = writer.toString();

This is it. Enjoy.

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Update your Scene in JavaFX

Usually it is very simple to update your scene in JavaFX. For example if you want to update the X and Y position of your nodes, you can often simply do some stuff like:

node.setLayoutX(100d);
node.setLayoutY(150d);

But this isn’t a good way of doing it. In JavaFX you have to be sure you are in the JavaFX application thread. But how can you know this?

Platform.isApplicationFxThread();

But what if you’re not in that thread?

Platform.runLater(Runnable r);

So each time you would like to update your scene manually, you should check if you’re or not in the FX application thread. So let’s make a really simple helper class:

/**
 * @author Thierry Wasylczenko
 */
public class PlatformHelper {

    public static void run(Runnable treatment) {
        if(treatment == null) throw new IllegalArgumentException("The treatment to perform can not be null");

        if(Platform.isFxApplicationThread()) treatment.run();
        else Platform.runLater(treatment);
    }
}

The method run does the check for you. Finally you can use a lambda expression to execute that code:

final Node node = ... ;
PlatformHelper.run(() -> {
  node.setLayoutX(100d);
  node.setLayoutY(150d);
});

That’s it.

PathTextField: quick example of property usage in JavaFX

Context

Properties and binding in JavaFX is a really interesting feature that sometimes is hard to illustrate. Recently I just faced a problem in CompilerFX: file paths entered by the user could be problematic. Indeed on some platforms path separator is \ and on others it is /. In Java you can often use / as path separator.

Practice

So in our example, you can choose many solutions like for example:

  • When the user submit the path in a text field, replace all \ by /;
  • When the user enter a \, use a key event to replace it;
  • Choose a more JavaFX way.

Let’s deal with the third solution. Have this ones in mind:

  • In JavaFX you have the properties, allowing you to listen for a change using a ChangeListener;
  • The text of a TextField is store in the text property.

You could implement the second solution listen previously but let’s work with a custom text field that will replace replace all \ by /.

public class PathTextField extends TextField {

  {
    textProperty().addListener(new ChangeListener<String>() {
      @Override
      public void changed(ObservableValue<? extends String> observableValue, String s, String s2) {
        if(!textProperty().isBound() && s2 != null) {
          textProperty().set(s2.replaceAll("\\\\", "/"));
        }
      }
    });
  }
}

In this component, we place a ChangeListener on the text property in order to replace all \ by /. Then you can use it in your FXML files for example.

TableView and ListValueFactory in JavaFX

The TableView control is pretty complete to use and very convenient. But the classical use of it specify that a line is represented by an instance of an Object, usually a property bean. But in some cases it would be very useful to have a line composed by multiple instances of a specific class, i.e. having an instance per column, and each column should display a particular property of your instance. A concrete example would be the management interface of translations in NetBeans. Indeed, this screen display all properties files of a particular resource bundle, having a column for the translations keys and as many columns as needed to display the translations for each keys.

netbeans_i18n_editor

As said above, we could need an instance of object per column, meaning multiple instances per line. So a line of the TableView should be a List<? extends Object>. The problem is to know which data to display in a particular column.

ListValueFactory

As you may know, you can set CellValueFactory on a TableColumn, which will display the value in the cell. For example, you can set a PropertyValueFactory that will look for a property of a bean, and will display it. But that works if you have a single Object per line, not a collection. So we will create our own implementation that will check a property of a bean inside a list.

public class ListValueFactory<T, V> implements Callback<TableColumn.CellDataFeatures<List<T>, V>, ObservableValue<V>> {
  
  private String propertyName;

  public ListValueFactory(String propertyName) {
    this.propertyName = propertyName;
  }
    
  @Override
  public ObservableValue<V> call(TableColumn.CellDataFeatures<List<T> , V> p) {
        
    int index = 0;
        
    ListIterator<TableColumn<List<T>, ?>> iterator = 
       p.getTableView().getColumns().listIterator();
        
    TableColumn tmpColumn;
    while(iterator.hasNext()) {
      tmpColumn = iterator.next();

      if(tmpColumn == p.getTableColumn())
        break;
      else
        index++;
    }

    T object = p.getValue().get(index);

    try {
      Method method = object.getClass().getMethod(propertyName.concat("Property"));
      return (Property<V>) method.invoke(object);
    } catch (Exception ex) {
      Logger.getLogger(ListValueFactory.class.getName()).log(Level.SEVERE, null, ex);
      return null;
    }
  }
}

As you can see, the implementation is totally generic. First, we try to know the index of the column and we suppose that this index is the same index of the data in the list of data. WARNING: this is totally wrong if, in your UI, you move columns ; so take this into consideration because the implementation is not shown here. Once we have the index, we look for the data in the list, and finally, using so introspection, we look for the getter of the property in order to get the value. And that’s it.

Usage

To use this implementation in your code, you juste have to do the following:

TableView<List<Person>> tableView = new TableView<>();
TableColumn<String> columnOne = new TableColumn<>("First name one");
columnOne.setCellValueFactory(new ListValueFactory<List<Person>, String>("firstName"));
TableColumn<String> columnTwo = new TableColumn<>("First name two");
columnTwo.setCellValueFactory(new ListValueFactory<List<Person>, String>("firstName"));
tableView.getColumns().addAll(columnOne, columnTwo);

“Bind” components’ size to a MediaView’s size in JavaFX

The MediaView is a control allowing you to add videos and sounds to your JavaFX application. If you are playing a video, maybe you would like another control to have the same size. For example, you can have a video played next to an image that you would like to have the same height. The easy thing would like to do some property binding like this:

final MediaView mediaView = new MediaView(aPlayerInstance);
mediaView.setFitWidth(200);

final ImageView imageView = new ImageView(anImageInstance);
imageView.fitHeightProperty().bind(mediaView.heightProperty());

But this code is wrong because the MediaView doesn’t have a height property. So in order to succeed in our goal, the MediaView has a boundsInLocalProperty which can be used to change the size of the ImageView in our case. Look at this code example:

final MediaView mediaView = new MediaView(aPlayerInstance);
mediaView.setFitWidth(200);

final ImageView imageView = new ImageView(anImageInstance);

mediaView.boundsInLocalProperty().addListener(new ChangeListener<Bounds>() {
  @Override
  public void changed(ObservableValue<? extends Bounds> observableValue, Bounds bounds, Bounds bounds2) {
    imageView.setFitHeight(bounds2.getHeight());
  }
});

Of course you have to do some nullity checks to make your code more robust.

Set custom font in JavaFX 2

Maybe you would like to set custom fonts to your application for various reasons: make it touchy, be compliant with your corporation with corporate font, and so on. In JavaFX it’s pretty easy to change the font of a component. You can use the Labeled#setFont(Font f) method in your code, or define the -fx-font-family in your CSS. But what about custom fonts?

Load the font

The first thing you have to do is load the font. This is done like this:

Font.loadFont(SomeApp.class.getResource("/com/twasyl/someapp/font/MyFONT.TTF").toExternalForm(), 12);

This loads your font, which has a family, let’s say Thierry Font. This method makes the font available in your graphics environment and you just have to use it whenever you want. I like to place this code in my Application class, especially in the init method, so the I’m sure the font is loaded before any other treatment (especially before any labeled element is rendered). Let’s write this code:

public class SomeApp extends Application {

  @Override
  public void start(Stage stage) throws Exception {
    // Do some stuff
  }

  @Override
  public void init() throws Exception {
    super.init();

    Font.loadFont(SomeApp.class.getResource("/com/twasyl/someapp/font/MyFONT.TTF").toExternalForm(), 12);
  }

  public static void main(String[] args) {
      SomeApp.launch(args);
  }
}

Use your custom font

Punctual use

Either in your FXML or CSS code, you can now define the -fx-font-family with the value Thierry Font.

<Label style="-fx-font-family: 'Thierry Font'" />

This label will use the font, but what about the others elements? Do I really have to do this on ALL elements? Of course not …

General use

The interesting part is you can define your font for the whole application by default. Indeed in your CSS you just have to do this:

.root {
  -fx-font-family: 'Thierry Font';
  -fx-font-size: 15pt;
}

By default every labeled element will use your custom font. And of course you can change the font for a particular label again, using the style attribute for example.

Build JavaFX runnable JAR with IntelliJ IDEA (and Ant)

For years now I’ve been using NetBeans and I’m satisfied about it. But I wanted to give IntelliJ IDEA a try so I decided to test it by creating some JavaFX apps. And if you’re following the news, JetBeains has released IntelliJ IDEA 12. The thing is IntelliJ doesn’t have specific JavaFX features so I really wanted to see how to deal with it. Since JavaFX 2 is a part of the JDK 7 now, you won’t face any problem according like the JavaFX classes. The “problem” is I really have my habits on NetBeans and it is kind of difficult to throw them away. And one of my first problem was: how do I create a runnable JAR for my JavaFX app? Well I know the stuff about Ant tasks, the JavaFX packager in theory. But I didn’t had to really know them in details because NetBeans really does everything for you.
To be very clear: I won’t judge neither NetBeans, neither IntelliJ. Both have their pros and cons and both are great products. The subject here is really to focus on how to create a runnable JavaFX JAR in IntelliJ using Ant. And because I am really a newbie to IntelliJ, I hope this post could help others.

Configuration and tools

The configuration and tools that is used:

  • OS X Lion or Mountain Lion
  • Java 7u9 (with JavaFX 2.2.3)
  • IntelliJ IDEA 12 CE
  • Ant (shipped with the IDE)

The project I’m using is a simple project that you can grab here.

The Ant build script

First thing we have to do is to create the Ant build script. Go to Build > Generate Ant Build …
IntelliJ_Generate_Ant_build_script_01
Then create the script by giving it a name. I personally decided to make it as simple as possible.
IntelliJ_Generate_Ant_build_script_02
After that, I replaced the whole generated content of the build script by the following one:

<?xml version="1.0" encoding="UTF-8"?>
<project name="testerfx" default="default" basedir="." xmlns:fx="javafx:com.sun.javafx.tools.ant">

  <property name="java.home" value="/Library/Java/JavaVirtualMachines/jdk1.7.0_09.jdk/Contents/Home"/>
  <property name="source.dir" value="src"/>
  <property name="out.dir" value="build"/>
  <property name="out.dir.classes" value="${out.dir}/classes" />
  <property name="out.dir.dist" value="${out.dir}/dist"/>
  <property name="app.jar.name" value="TesterFX.jar"/>

  <path id="classpath">
    <fileset dir="${java.home}/lib" includes="**/*.jar"/>
  </path>

  <target name="default">
    <taskdef resource="com/sun/javafx/tools/ant/antlib.xml"
                 uri="javafx:com.sun.javafx.tools.ant"
                 classpath=".:${java.home}/lib/ant-javafx.jar"/>
  </target>

  <target name="clean">
    <delete dir="${out.dir}"/>
  </target>

  <target name="init" depends="clean">
    <mkdir dir="${out.dir}"/>
    <mkdir dir="${out.dir.classes}"/>
    <mkdir dir="${out.dir.dist}"/>
  </target>

  <target name="compile" depends="default, init">
    <javac srcdir="${source.dir}" destdir="${out.dir}/classes" classpathref="classpath"
               source="1.7"
               target="1.7" />
    <copy todir="${out.dir}/classes">
      <fileset dir="${source.dir}">
        <include name="**/*.png" />
        <include name="**/*.fxml" />
        <include name="**/*.css" />
      </fileset>
    </copy>
  </target>

  <target name="build" depends="compile">
    <fx:application id="TesterFX" mainClass="com.twasyl.testerfx.app.TesterFX"/>
    <fx:jar destfile="${out.dir.dist}/${app.jar.name}">
      <fx:application refid="TesterFX"/>

      <manifest>
        <attribute name="Implementation-Vendor"
                           value="Thierry"/>
        <attribute name="Implementation-Title"
                           value="TesterFX"/>
        <attribute name="Implementation-Version" value="1.0"/>
      </manifest>

      <fileset dir="${out.dir.classes}"/>
    </fx:jar>
  </target>
</project>

If you’re familiar with Ant, this is pretty easy: I define some basic targets for cleaning and compiling. The most interesting part is the target build. It is there that the final jar for our application is done using some new tags like:

  • fx:application that represents our JavaFX app, where you define the application class, the fallback one and so on ;
  • fx:jar that will create the final JAR by assembling the classes, convert CSS files into binary format if wanted and so son.

Of course there are other tags like fx:deploy, fx:signJar, etc. But here we only wanted to build a simple JAR without any particular configuration.

Try it

Once your build script is ready you just have to execute the build target to get your runnable JAR. To do so, at the right of IntelliJ click on Ant Build and then on the + in order to add your build script.IntelliJ_Generate_Ant_build_script_03
Choose your file:
IntelliJ_Generate_Ant_build_script_04
And then you will be able to execute targets you want.
IntelliJ_Generate_Ant_build_script_05

That’s it. I hope this could help you.

Useful resources