Tag Archives: javascript

FX Playground




Update: The FX Playground project can be found at: https://bitbucket.org/cdea/fxplayground



FX Playground is a JavaFX-based prototyping tool or live editor that eliminates the step of compiling Java code. This concept isn’t new, for instance the Web world there are many HTML5 playgrounds that offer online editors that enable developers to quickly prototype or experiment with various JavaScript libraries. This allows the developer to focus on visualizations or UI details without needing to set-up an IDE project or mess with files. Even older (pre-dating) than playgrounds are REPLs (Read Eval Print Loop) where dynamic languages such as Groovy, Python, Ruby, etc. provide an interactive interpreter command line tool to allow developers to quickly script code to be executed. Scala is a compiled language, but also provides a REPL tool.

After finishing the book JavaFX 8 Introduction by Example I noticed each example was created as separate NetBeans projects which seemed a little overkill for small examples. Because the book is based on Java the language each program needed to be compiled (via javac) prior to execution. Larger projects will typically need to be set-up with a proper classpath and resources in the appropriate directory locations. Even larger projects will also need dependencies which typically reside on Maven repositories.

JavaOne 2014

Based on timing I was able to submit a talk regarding JavaFX based playgrounds just in time. After awhile I was pleasantly surprised that my proposal (talk) was accepted. You can check out the session here. Also, I will be presenting with my good friend Gerrit Grunwald (@hansolo_). So, be prepared to see awe-inspiring demos. Since the talk is a BoF (birds of a feather) the atmosphere will be low-key and very casual. I hope to see you there!

The JavaOne talk is titled “JavaFX Coding Playground (JavaFX-Based Live Editor Tool) [BOF2730]”.  Based on the description you’ll find that the tool will be using the NEW! Nashorn (JavaScript) engine to interact with JavaFX primitives. The figure below depicts the FX Playground tool’s editor windows and a JavaFX Display area. Starting clockwise at the lower left is the code editor window allowing the user to use JavaScript (Nashorn) to interact with nodes. Next, is the JavaFX FXML editor window allowing the user to use FXML (upper left). The FXML window is an optional.  In the upper right, you will notice the JavaFX CSS editor window allowing you to style nodes on the display surface. Lastly, to the bottom right is the output area or better known as the DISPLAY_SURFACE.

FXPlayground's editor windows

FXPlayground’s editor windows

FX Playground in Action

Because FX Playground is still in development I will give you a glimpse of some demos that I’ve created on Youtube. The following are examples with links to videos.



There are plans to opensource the code, but for now there is much needed functionality before public consumption.

The following features are a work in progress:

  • Make use of FXML editor window.
  • Pop out the display panel into its own window
  • Save, SaveAs, and Load Playgrounds
  • Build software to be an executable for tool users. (90% done)
  • Make the tool capable of using other languages (JSR 223)

I want to thank Oracle corp. especially the following engineers who helped me (some of the engineers below are not Oracle employees):


The FX Playground project can be found at: https://bitbucket.org/cdea/fxplayground

CarlFX’s Channel – https://www.youtube.com/channel/UCNBYRHaYk9mlTmn9oAPp1VA

7 of the Best Code Playgrounds – http://www.sitepoint.com/7-code-playgrounds

NetBeans – https://www.netbeans.org

JavaFX 8 Introduction by Example – http://www.apress.com/9781430264606

Nashorn – https://wiki.openjdk.java.net/display/Nashorn/Main

Enzo – https://bitbucket.org/hansolo/enzo/wiki/Home

Harmonic Code – http://harmoniccode.blogspot.com/

A Case Study: A JavaFX Widget Framework API

A prototype of a widget container

A prototype of a widget container

Building a better mousetrap

In short I want to revisit the idea of a cross platform widget framework using JavaFX. In this article I’d like to share some ideas, concepts and prototypes that might invigorate this old but ingenious idea for the desktop and embedded world. An old idea you say? Does anyone remember WidgetFX?

In the early days of JavaFX there were a few Java Champions and community members who decided to create a cross platform JavaFX 1.x widget framework for the desktop (year 2008). I was fortunate enough to know many of those contributors involved.  I grew to love the capabilities the framework and widgets were able to provide.  However, as we all know JavaFX is now redone as Java APIs as opposed to the JavaFX script language. This eventually became apparent regarding to the future of most frameworks back then. Before I begin I would like to give credit to the folks who contributed to the WidgetFX framework project.  I want to thank them for their enthusiasm and their tireless efforts on building the community to what it is today. To see some of their cool widgets please visit the site http://widgetfx.org (catch them before they’re gone). Two of the original founders of the project are Stephen Chin and Keith Combs. Even though I did not partake in the fun during the height of the project I was quite inspired.

Inception phase

To fast forward just last year at the JavaOne 2012 conference I was able to catch up with Keith Combs (Silicon Valley JavaFX User Group organizer) and Stephen Chin (Java Technology Evangelist at Oracle) after his keynote speaking to inquire about the WidgetFX project now that JavaFX 1.x is no more. Steve kindly asked if anyone would be interested in giving it a reboot on the JavaFX 2.x platform (As he peered over towards Keith and me). I believe I said, “I don’t think, so… “. I thought it might be too much to bite off than I could possibly chew. So I politely declined the offer. During the conference I was later enamored by all things Java embedded which later fueled to some of my home automation project ideas using JavaFX with (Arduino, Raspberry Pi, and Beagle Board).

After returning home I was not only excited about the things I’ve learned at the conference but, I also was in the middle of transitioning to a new job and company. Working as a UI and Visualization developer for cloud based monitoring software I often encountered stakeholders/SMEs mentioning the term “SPOG” or single pane of glass.

What does the term “SPOG” mean?

According to Floyd Strimling a cloud technical evangelist at Zenoss explains how so many organizations will create desperate (silos) systems and he goes on to say, “The Holy Grail is a single pane of glass that provides IT managers with a single access point to make sense of their entire underlying infrastructure in real time”. (Searching for the Mythical Single Pane of Glass)

Isn’t “SPOG” an interesting concept for large operation centers? So, I continued to rethink of the old idea of a flexible widget framework that would provide richer interfaces that would allow better desktop integration, decoupled services, higher performance, and capable of empowering users with many of the modern UI metaphors that they’d expect on their favorite OS platform. I believe such a framework should also work on embedded devices for home automation.  Actually I got the idea of a widget framework for embedded devices from my good friend Gerrit Grunwald (Java Champion and author of the popular Steel Series API) while exchanging ideas about graphics performance and launching JavaFX applications on embedded devices.

Wow, with so many different problem domains and so many perspectives could such a widget framework truly exist? Could such a widget framework be able to make everyone happy? Is it possible to create a simple widget framework to rule them all? I believe it is possible.

eWidgetFX is born

In the back of my mind I noticed similar use cases with many customers wanting widget frameworks having this concept of a “SPOG”, but also provide a framework that I could use myself on my own desktop or touch device. So, I kept going back and forth on the possibility of rebooting the old project WidgetFX. Instead I wanted to throw a monkey wrench into the whole business of widget frameworks. Since there are so many kinds of ways to launch, display, and manage widgets it would also be a good idea to build a single widget framework SPI (service provider interface API) which would enable developers to build their own widget containers thus allowing widget developers to run their widgets in any widget container. There would basically be two developer perspectives: Container Developers and Widget Developers. So, I’d like to propose a new API called eWidgetFX (core) that would allow the developers to create widget containers and widgets.

For now I will defer the work of designing the core APIs and make it a future post. So, in this article I’ve decided to generate some prototypes of widget containers that would basically depend on the future eWidgetFX framework API.

Prototyping Widget Containers

Prototyping is probably the most fun part during any software development activity. Shown below are videos I recently uploaded to Youtube.com to kick some ideas around for different kinds of widget containers (Icon App tray) on a desktop environment.


One of the main issue I found in UI development is that customers will often know what they want, but aren’t able to communicate what they ultimately want. It’s almost like playing a game of Charades or a game of Pictionary where guessing is a sought after skill in software design.  We are often faced with providing prototypes and end up settling on one particular view (one view, one way, one silo). The problem became pretty apparent where everyone had an opinion or philosophical stance on a particular GUI interface, usability aspect or UI metaphor. Sometimes it’s based on subjective personal preferences that can go into long discussions. No one person in the room was completely happy, but at the end of the day we compromised and we settled.

I believe that by creating a widget API it would allow organizations to build different single pane of glass instances (widget containers) and capable of sharing all widgets across other panes.

So, imagine seeing different types of widget containers in the wild. Some future widget containers could look like interfaces similar to the following movies: Avengers, Tron, or Minority Report

A final note: Many of of the ideas expressed and proposed are a collective effort from some of my friends (team members) of the JFXtras.org project (Mark Heckler, Hendrik Ebbers, and Gerrit Grunwald).

Would you like to see a talk regarding widget frameworks at JavaOne?

As always comments are welcome.

Carl 😉


JavaFX: http://www.oracle.com/technetwork/java/javafx/overview/index.html
Java Champions: https://java.net/website/java-champions/bios.html
WidgetFX: http://widgetfx.org
Keith Combs from the Silicon Valley JavaFX user group: http://www.svjugfx.org/member/10394895/?op=&memberId=10394895
Steve on Java by Stephen Chin: http://steveonjava.com
Arduino : http://www.arduino.cc
Raspberry Pi: http://www.raspberrypi.org
Beagle Board: http://beagleboard.org
Guest Post: Searching for the Mythical Single Pane of Glass: http://siliconangle.com/blog/2012/02/29/guest-post-searching-for-the-mythical-single-pane-of-glass
Anti-patterns: http://en.wikibooks.org/wiki/Introduction_to_Software_Engineering/Architecture/Anti-Patterns
Google Images of Operation centers: http://bit.ly/106p3h0
Avengers UI design: http://cargocollective.com/jayse/Avengers
Tron UI design: http://dlew.me/Tron-Legacy-Boardroom
Minority Report UI designer demos his tech at TED (video): http://www.engadget.com/2010/06/03/minority-report-ui-designer-demos-his-tech-at-ted
The Java Jungle by Mark Heckler: https://blogs.oracle.com/javajungle/entry/welcome_to_the_jungle
Gui Garage by Hendrik Ebbers: http://www.guigarage.com
Harmonic Code by Gerrit Grunwald: http://harmoniccode.blogspot.de
JFXtras.org : http://jfxtras.orgLeap Motion: https://www.leapmotion.comLeap Motion: https://www.leapmotion.com

JavaFX to JavaScript and Back Part 2

Tons of Bouncy Balls

Tons of Bouncy Balls


In the second installment of the series “JavaFX to JavaScript and Back” we will look at code! If you remember what we discussed in my previous post of Part 1 showing a demo of many bouncy balls. If you want to skip to the source code go to demo and click on download project.


If you are new and just getting started with JavaFX I strongly suggest JavaFX.com or Java.sun.com. If you are like me, one who knows enough to be dangerous please skip to Getting Started. Newcomers should take a look at books in the References section at the end of this article. Another awesome resource is the “Free” 15-Week JavaFX Programming (with Passion!) Online Course w/ Sang Shin & James Weaver.


  • NetBeans 6.5.1 is installed with JavaFX 1.2 pluggin.
  • Java SDK 1.6 update 14
  • Know basic JavaScript
  • Know basic HTML

Getting started

To give you a quick recap of the scenarios:

  1. Create Bouncy Balls (JavaScript to JavaFX)
  2. Remove Bouncy Balls (JavaFX to JavaScript)

Create a JavaFX Applet

Step 1: Create a Ball (Custom Node)
First create a class called Ball that extends a CustomNode. The key is overriding the create() method of the CustomNode class. We first create a Circle with a RadialGradient fill. Next we create a Group containing the circle in its content attribute. Then add the onMousePressed function to the group to detect a mouse pressed event which will remove this ball’s instance from the Scene (Game Area) and decrements the numBalls variable which updates the Web Page’s form element Number of Balls. Finally we return the group (ball variable).

class Ball extends CustomNode {
    public var velocity:Velocity;
    public var centerX:Integer=100;
    public var centerY:Integer=100;
    public var radius:Integer;
    public var fill:Color;
    protected override function create(): Node {
        var circle:Circle = Circle {
                centerX: centerX, centerY: centerY
                radius: radius
                fill: RadialGradient {
                        centerX: centerX - radius / 3
                        centerY: centerY - radius / 3

                        radius: radius
                        proportional: false
                        stops: [
                            Stop {
                                offset: 0.0
                                color: getRndColor()
                            Stop {
                                offset: 1.0
                                color: Color.BLACK
                        ] // stops
                } // RadialGradient
        } // circle
        var ball = Group{
            // remove ball
            onMousePressed: function( e: MouseEvent ):Void {
                delete this from gameArea;
        } // Group

        return ball;
    } // create()
} // Ball

Step 2: Create initial ball to be put in Scene

You should notice I’ve created a few script level functions which conveniently return random values to create a Ball node. I won’t list those function for brevity. The random generated attributes are: velocity, centerX, centerY, radius, circle.fill = (RadialGradient 1st stop Color [Step 1 – Line 19])

// create an initial ball to float around.
var initialBallRadius = getRndRadius();
var rndCenter:Point = getRndCenter(500, 400, initialBallRadius);
var firstBall = Ball{
    centerX: rndCenter.x
    centerY: rndCenter.y
    radius: initialBallRadius

Step 3: Create the Scene to display Balls
The variable gameArea is a sequence of Nodes. You will notice the ball instance from Step 2 is the first node in the sequence. The scene’s content attribute is bound to the gameArea variable. During run time as nodes are added and removed from the game area the scene will dynamically update the visible nodes.

var gameArea:Node[] = [firstBall, toggleAnimationButton, mainRectRegion];
var scene:Scene = Scene {
        content: bind gameArea

Step 4: Create the Stage
This is the top level container which holds the scene.

Stage {
    title: "Application title"
    width: 500
    height: 400
    opacity: bind mainScreenOpacity;
    scene: scene

Step 5: Create a game or animation loop using the Timeline class
Here we create a Timeline instance that will run indefinitely (Timeline.INDEFINITE) with a single key frame (KeyFrame) which periodically updates each bouncy ball’s attributes which eventually renders each ball node with a new x and y position based on the velocity. Also the Timeline (gameLoop) is started immediately using the play() function.

var gameLoop:Timeline = Timeline {
    repeatCount: Timeline.INDEFINITE
    keyFrames : [
        KeyFrame {
            time: 1s / 50
            canSkip : true
            action: function() {
                for (node:Node in gameArea) {
                    if (not (node instanceof Ball)){
                        continue; // don't update non balls
                    var ball = node as Ball;
                    var xMin = ball.boundsInParent.minX;
                    var yMin = ball.boundsInParent.minY;
                    var xMax = ball.boundsInParent.maxX;
                    var yMax = ball.boundsInParent.maxY;

                    // Collision - boundaries
                    if (xMin  scene.width){
                       ball.velocity.xVelocity = ball.velocity.xVelocity * -1;
                    if (yMin  scene.height){
                       ball.velocity.yVelocity = ball.velocity.yVelocity * -1;

                    ball.translateX = ball.translateX + ball.velocity.xVelocity;
                    ball.translateY = ball.translateY + ball.velocity.yVelocity;
            } // action
        } //

Step 6: Create the AppletStageExtension
This is the reference to the JavaFX applet which would assist with browser functionality such as the evaluation of JavaScript code.

var applet: AppletStageExtension;

Step 7: Create the numBalls variable keeping track of adds and removes.
The numBalls variable has a trigger (on replace) that updates the HTML page’s input text field “numBalls“. You should notice the id attribute of the tag is name “numBalls“. An id is a way to uniquely locate the form element in the HTML DOM (in this case a reference to the input field. When numBalls variable changes the trigger will evaluate the JavaScript code “document.getElementById(‘numBalls’).value = {numBalls}”. What this does is populate the form element field’s ‘id’ called “numBalls” whenever the JavaFX variable numBalls is updated.

var numBalls:Integer = 1 on replace {
    applet.eval("document.getElementById('numBalls').value = {numBalls}");

Step 8: Create a JavaFX function to add lots of balls

The HTML Web page will have a JavaScript function that would call the JavaFX function below when the user presses the Add Ball(s) button.  javafxtojavascriptandback8You will notice the FX.deferAction() call, which ensures updates to JavaFX classes are happening on the JavaFX main processing thread. This function will instantiate num balls inserts into the game area (Scene content) and increments the numBalls (trigger will update Web page’s form element).

// This function is called from the JavaScript button and numBallsToAdd field
function addBalls(num:Integer) : Void {
    FX.deferAction(function() : Void {
        for( i in [1..num]){
            var curBallRadius = getRndRadius();
            var rndCenter:Point = getRndCenter(500, 400, curBallRadius);
            var b = Ball{
                centerX: rndCenter.x
                centerY: rndCenter.y
                radius: curBallRadius
                fill: getRndColor()
            insert b into gameArea;

Create a HTML Web page containing the JavaFX applet

Step 9: Create HTML Web page to display JavaFX applet

Run in Browser

Run in Browser

After creating the project in NetBeans select project / properties / Run (categories) / Application Execution Model – Run in Browser.

Step 10: Build Project

Building the project which will create files in the {PROJECT_HOME}/dist directory.

Step 11: Copy originally NetBeans created HTML file of the dist directory to another name

Use the copied and renamed HTML file and not the original because when the build process occurs it will overwrite the original HTML generated file.

Step 12: Modify HTML code to contain JavaScript to call JavaFX applet.

              archive: "JavaFXtoJavaScript.jar",
              draggable: true,
              width: 500,
              height: 400,
              code: "javafxtojavascript.Main",
              name: "JavaFXtoJavaScript",
			  id: "ballApp"
		{ isApplet: "true" }

function addBalls() {

Step 13: Modify HTML to contain Form Elements.

<tr><th>Add balls to Scene :</th>
<td><input id=”numBallsToAdd” name=”numBallsToAdd” value=”1″/></td>
<td><input onClick=”addBalls();” type=”button” name=”addButton” value=”Add Ball(s)”/></td>
<th>Number of balls: </th>
<td><input id=”numBalls” name=”numBalls” READONLY/></td>

Running Applet in Browser through NetBeans

Step 14: Run application or hit F6 key

This will launch the JavaFX applet into the browser from the original HTML page created from the build. Go to the address and modify the URL (Just the file name) to use the modified copy which would run the JavaFX applet along with the form elements added from step 12 – 13.


Although the example only used simple attributes of the AppletStageExtension there are other properties and events to explore such as onAppletRestored, showDocument(), etc.  Hopefully we can get away from HTML and just have rich client applications, however I don’t think the browser is going away anytime soon. So we can happily go from JavaFX to JavaScript and Back!

Enjoy. Let me know what you think.


Pro JavaFX Platform by Jim Weaver, Weiqi Gao, Stephen Chin, and Dean Iverson
JavaFX: Developing Rich Internet Applications by Jim Clarke, Jim Connors and Eric J. Bruno
Essential JavaFX by Gail Anderson and Paul Anderson


JavaFX to JavaScript and Back Part 1


One of the most impressive features that I’ve seen relating to JavaFX, is the ability of an Applet to interact with the browser via JavaScript and HTML. The browser can also interact back with JavaFX code. There are plenty of examples out there but I’d like to add one more to the pile of cool examples. It may be cool using AJAX concepts with JavaScript & HTML, but using the concept with JavaFX is just amazing. The possibilities are endless. “JavaFX to JavaScript and Back Part 1” will demonstrate what the application will do and “JavaFX to JavaScript and Back Part 2” will be on steps on how-to do it.

While I was a kid growing up, I would go to the bowling alley to get a 25 cent(US) bouncy ball from the vending machine. I’ve lost many a bouncy ball in the parking lot from bouncing them as hard as I could. In this example I will create a 500 by 400 pixel sized bouncy ball containment field in JavaFX. This is to prevent them from ever leaving me like they did when I was a kid. 😦

Note: Thanks to Stephen Chin an author of the book Pro JavaFX Platform and WidgetFX for allowing me to host The Bouncy Ball Containment Field Click Here to run!

(Tip: If in Firefox just middle mouse click link to launch in another tab)

Initial Ball added to ball world

Here is an example of an HTML page with an embedded JavaFX applet with HTML form elements below for data input to create bouncy balls. The demo allows a user to specify the number of balls to add to the scene called the “Add balls to Scene” field.  When the “Add Ball(s)” button is pressed the JavaScript code will pass the number of balls to the JavaFX public script level function called addBalls() which will create bouncy balls. When balls are added the JavaFX Script code will talk back to the HTML read-only field called “Number of balls” to show the current number of balls in the containment field (Scene). On the JavaFX side of things the location, velocity, size and color of the balls will be generated randomly and rendered on the scene.  You should notice the new JavaFX 1.2 Toggle Button component on the upper left. It is used to stop and  start the animation of the bouncing of the balls (Timeline pause & play to be exact). The first use case scenario is add balls which depicts the JavaScript to JavaFX data flow. The second use case scenario is display the current number of bouncy balls in the containment field which depicts the JavaFX to JavaScript data flow.

Balls addBalls(lots of balls)

This shows when the user specifies a whole bunch of balls to add.

Button to use JavaScript function addBalls()
Button to use JavaScript function addBalls()

A ball can be removed from the scene by just clicking an individual ball.  The field “Number of balls” input field is really a read-only field that is updated from the JavaFX side whenever balls are added and removed from the bouncy ball containment field.

More Bouncy Balls

By adding many balls I wanted to see how well it would perform.

Tons of Bouncy Balls

Here I add balls, lots of balls! The bouncy ball containment field now holds 400 bouncy balls. Although I might not be doing things efficiently I noticed my CPU was performing adequately. The utilization was between 41% to 46% (older Dell hyper-threading Inspiron XPS laptop Pentium(R) 4 CPU 3.40 GHz) using Windows XP SP 3. It was a smooth animation with no flicker. The Ball class is a Custom Node which contains a Circle with an effect called Radial Gradient to give it a 3D sphere look.

Dragging JavaFX Applet out of Web Page

By using the Alt key along with mouse drag the JavaFX applet will appear to be pulled out of the browser’s Web page and out onto the desktop.

JavaFX Applet living outside of browser

By default, when you drag the applet out of the browser onto your desktop a small “close button” appears on the upper right corner of your application. When the user clicks the “close button” box the JavaFX applet will snap right back into the browser. Another thing to note is that when the JavaFX applet is running outside the browser and the user subsequently closes the browser the applet will remain running independent of the browser.   This introduces an interesting ability that adds a new dimension to usability on the desktop.  As the user becomes drawn into the application experience the need to be attached to the Web page will be obsolete. Another cool effect that I have added to the Application is transparency or opacity level when the mouse cursor is exiting or entering the scene area. When the user moves the mouse away from the application the screen will fade to a subtle transparency. When the user moves the mouse cursor into the application screen area the background becomes fully opaque (white in this case).

Fully Opaque when mouse moves into application

Fully Opaque when mouse moves into application

This fading effect helps the user transition from one application to another.

The last, item of the desktop experience to mention is the Java JNLP mechanism that asks the user if he or she wants to create a short-cut icon for the application to launch at a later time.

Create short-cut dialog

Create short-cut dialog

To reproduce the dialog asking for a shortcut, you would drag the applet out of browser, then close tab or browser application and then a dialog will appear asking to create the short-cut.


Building the bouncy ball containment field was extremely fun. I learned a lot about boundsInParent which taught me that it is the rectangular region after all transformations to the node has been applied when adding balls to the Scene. As the future of the Web 2.0 apps grow users will demand richer interfaces and better content. I believe JavaFX has made great strides in desktop development and also increasing the usability factor of desktop applications by leaps and bounds. In Part 2 of “JavaFX to JavaScript and Back” I will detail a step-by-step tutorial on how to build the JavaFX applet you see here. Let me know what you think. Feedback is always welcome!