James Weaver on Quantum Computing and Java

BindListBoxToSequence (JavaFX Puzzler 3) Results and Sample Solution

Congratulations to Lucas Benedicic for submitting the first solution to the BindListBoxToSequence Puzzler, and the fact that it met the requirements of the problem!

For reference, here is my sample solution, followed by the screenshot:

/*
 * BindListBoxToSequence.fx
 */
 
import javafx.ui.*;

class ListBoxModel {
  attribute entries:String*;
}
attribute ListBoxModel.entries = [];

Frame {
  var model = 
    ListBoxModel {
    }
  var elementTextField =
    TextField {
      columns: 12
    }
  title: "Bind ListBox to Sequence Puzzler"
  content:
    BorderPanel {
      top:
        FlowPanel {
          content: [
            elementTextField,
            Button {
              text: "Add Element"
              defaultButton: true
              action:
                operation() {
                  insert elementTextField.value into model.entries;
                  elementTextField.value = "";
                }
            }
          ]
        }
      center:
        FlowPanel {
          content:
            ListBox {
              fixedCellWidth: 200
              cells: bind foreach (entry in model.entries)
                ListCell {
                  text: entry
                }
            }
        }
    }
  width: 400
  height: 250
  visible: true
}

Congratulations again, Lucas!  I'll contact you right away with instructions on downloading the JavaFX Script eBook.

Regards,
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications
eBook (PDF) download available at the book's Apress site

JavaFX Puzzler 3 - First Correct Solution Gets Free JavaFX Script eBook

This post contains JavaFX Puzzler 3, which will make use of some of the JavaFX concepts that you've learned from this blog, including ones that you've explored in the resources to which I've been pointing you (hint: especially the Learning JavaFX Script, Part 1 tutorial, and the ListBox section of the Learning More About the JavaFX Script Language Tutorial).  The first person to post a comment with a correct solution will be given a free JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications eBook (PDF download).  When submitting your answer, be sure to put your correct email address in the  "Email Address: (Not displayed with comment.)" text field on the comment form so that I can contact you with the information to obtain your free eBook.

Requirements for Puzzler 3: The BindListBoxToSequence Program

Here is a screenshot of the sample solution:

The requirements for this program are as follows:

1. The UI must have a similar, but not necessarily identical, appearance as the screenshot shown above.
2. The program must contain a class named ListBoxModel that contains an attribute named entries.  The entries attribute contains a sequence (array) of type String.  Note: ListBoxModel and entries are arbitrary names, not required by JavaFX Script.
3. When the user types a word into the text field and clicks the Add Element button, the word is added to the entries sequence.  The Add Element button must be the default button, so when the user types into the text field and presses the Enter key, the same result occurs.
4. The cells attribute of the ListBox must be bound to the entries attribute of the ListBoxModel, so as elements are added to the sequence, they appear in the ListBox.

By the way, if you're looking for some starter code like I supplied in the last Puzzler, you won't find any. :-D

Enjoy!
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications
eBook (PDF) download available at the book's Apress site

I Hear Voices - RIAs are the Future (Remix)

I remember how excited I was in 1995 when stumbling upon an alpha release of Java.  I was a Systems Architect for a large technology firm at the time, and had recently finished an evaluation of several cross-platform (Windows, Motif, Mac) application development tools.  The result of the evaluation was disappointing in that there seemed to be no good choice.  Then came Java... 

Applets, for me, represented a way that our company could deliver applications that were as rich in UI features as the C++/GUI toolkit applications that we had been developing for each of these platforms individually.  I began creating proof of concept applets on the Netscape Navigator browser, and looked forward to a happy future where Java applets would run on all browsers.  After all, it made sense (to me anyway) that the Java Runtime Environment should be included on all browsers.  Then came the browser wars...

To say that I (and much of the development community) was disappointed with results of the browser wars would be an understatement:

• Java applets, even with the Java Plug-in, never became a serious option for rich, cross-platform, internet applications.
• Technologies (e.g. HTTP and HTML) that were originally meant to share information, were suddenly being employed to support N-tier applications.  The fact that there are different flavors of HTML didn't help accomplish this feat.
• JavaScript, with its different flavors, became an enabler (in the co-dependent sense perhaps) of this trend.
• Many web-based applications today consist of various technologies, that when combined, are very difficult to maintain (again, an understatement).

I remember how excited I was in 2007 when stumbling upon an alpha release of JavaFX Script...

Can We Get this RIA Thing Right This Time?

I personally am not hung up on the Flex vs. JavaFX vs. whatever debate.  They all have their strengths, and there is room for more than one RIA technology.  I've been a Java developer and author since 1995, so I have a preference for being able to leverage the power of the Java and Java Swing libraries from the simple declarative scripting of JavaFX Script.  In fact, as you may have read between the lines of my book and blog, I'm quite enamored with JavaFX Script for developing rich internet applications, not to mention how cool it will be on mobile devices.

As I said in the Putting My CTO Hat On post, "What I'm really hoping for in the 2008-early 2009 timeframe is that the deployment for JavaFX applications (including the JRE) will be so fast and easy that we'll be writing rich-client JavaFX applications in most cases (rather than defaulting to browser-based applications)."  I'm betting that Compiled JavaFX Script and the technology formerly known as Consumer JRE will help get us there.

Some of the Voices I've Been Hearing

"Basically, I want what Java Applets promised 10 years ago, but in a form that actually works.  How does JavaFX and Java Web Start fit in with this?" -Paul Browne.  Visit Paul's blog.

"Java applets, or something like it, is having a comeback. And this time, it just might work. I'm not predicting that Sun will win. As a matter of fact, I wish every product in this space wins. However, what I can predict is that classical web app development will fade away as a viable IT option within 3 years. Surely Google and Yahoo and Amazon.com will still be putting out web apps, but for the most part, ordinary people won't be writing HTML or even thinking HTML anymore. -Weiqi Gao.  See "Java's Game Changing Move: The First Step" in Weiqi's blog.

"There's so much more that can be done, and I think this represents a potential flowering of the capabilities of the Internet. Notice I didn't say "the capabilities of the Web" but of the Internet, because it seems to me that the Internet has been held back by the web browser." -David Herring.  See "Freeing the Internet from the Web jail" in David's blog.

"Folks, the browser platform is passé. The race for the next round of cross-platform (note: not cross-browser) internet applications (note: not web applications) has already started. And my prediction is that JavaFX Script will win." -Weiqi Gao.  See "JavaScript To Fragment, The End Of The Reign Of The Browsers" in Weiqi's blog.

In the interest of full disclosure, Weiqi Gao is the technical reviewer of my JavaFX Script book (and he did an awesome job in reviewing it and providing technical input by the way).

Fair Warning on the Next JavaFX Puzzler

The next JavaFX Script Puzzler is planned to be posted at 18:00 GMT (1:00 pm EST) on Wednesday, November 14.  Study up! :-D

Regards,
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications
eBook (PDF) download available at the book's Apress site   

Learning the Fundamentals of the JavaFX Script Language

So far in this blog I've been showing you:

• How to write your first JavaFX Script program, and understand many of the concepts contained in it.
• How to use resources such as JavaFXPad and the Project OpenJFX download to develop and execute JavaFX programs.
• How to use simple declarative scripting to, among other things, leverage the power of Java Swing components.
• How to bind the UI (view) to the data (model).
• Examples of non-trivial JavaFX Script applications such as the Freebase Browser and the Word Search Puzzle Builder.
• My plans as a CTO for utilizing JavaFX Script within our company (LAT, Inc.)
• How to use the powerful layout widgets to help create user interfaces for a cross-platform environment
• Some of the 2D graphical features of JavaFX Script
• A few of the fundamentals of the JavaFX Script language, such as defining classes, attributes and triggers.

However, there are several JavaFX Script language fundamentals that I haven't covered in much detail, such as sequences (arrays).  At this point, I'd like to introduce you to a great tutorial created by Robert Eckstein and others at Sun that covers the fundamentals of the JavaFX Script language.  Parts of the tutorial will be an excellent review for you as well.  I highly recommend taking this tutorial, and besides, future JavaFX Puzzlers in this blog will assume that you did :-D

Enjoy!
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications

One More Canvas Example - JavaFX Clock by Chris Oliver

I've got one more Canvas/2D graphics related example to share with you (for now) before we switch gears (no pun intended) to another topic.  This example from PlanetJFX is an analog clock created by Chris Oliver, the founder of JavaFX Script, with some additions by Dean Iverson. 

This clock example utilizes several of the concepts that are demonstrated in the JavaFX Canvas tutorial (see the Release Your Inner Artist post for instructions on running this very cool tutorial).

Just cut and paste the code from the analog clock link above into JavaFXPad.  As a refresher, to run JavaFXPad directly from the Internet, see the instructions in the first post in this blog (it's really quick and easy).  To install and run JavaFXPad on your machine, see this post.

As you run and examine the code in this example, the following sections of the JavaFX Canvas tutorial will help you understand the main concepts used:

• User-Defined Graphics Objects: In JavaFX Script, you can create your own graphical custom components by sub-classing CompositeNode.  The clock example uses this technique so that it can be used as a component within a larger JavaFX Script application.
• Groups
• Transformations
• Animation
• Shapes

Have fun with this example!
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications

JavaFX Animation - Some of Sven's Canvas Tricks

Note: This post has been superseded by the Radar Love: JavaFX Animation Examples by Sven post, so please visit that page.

Sven Drieling, whose code examples have been featured previous posts, has some examples on PlanetJFX of animating and interacting with a rectangle.  There are four examples:

• The first example (RectMove.fx) is very much like the Red Rubber Ball solution in an earlier post, so you'll be in familiar territory at this point.
• The second example (RectResize.fx) is an example in which you can resize a rectangle by dragging the lower left corner.
• The third example (RectBounce.fx) animates a rectangle by making it bounce off the sides of a Canvas.  It uses the JavaFX dur operator to control the rate of movement.
• The fourth example (RectCatch.fx) uses the onMousePressed event to enable the user to "catch" the rectangle as it is bouncing around.

These examples begin to demonstrate, among other things, how you can create animated games in JavaFX Script.  Take a look at the code, and paste them into JavaFXPad.  You might want to run the JavaFX Canvas Tutorial program discussed in this post to refresh yourself on the Canvas/2D related techniques used in Sven's examples.

By the way, I just found out that I'll be presenting in two JavaFX sessions (a university session, and a conference presentation) at JavaPolis 2007 on December 10 - 14, in Antwerp, Belgium.  If you are in attendance, please introduce yourself as I'd like to meet you!

Regards,
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications

Would Like Your Feedback on Offering an Intensive On-Site JavaFX Script Class

I'm considering the idea of offering an intensive on-site course on JavaFX Script, and am trying to gauge the interest of the community in this.  Just brainstorming a bit, I've been thinking about offering a 2 - 3 day course that uses presentations and labs to give the students a working understanding of developing JavaFX Script applications.  I live in Indiana (US), so one possibility would be to teach the course at a location near the Indianapolis airport.  Another possibility would be for me to travel to a location in which several students have signed up to take the course.

Assuming the cost of the course is reasonable, do you see any merit in this idea?  Would you, or your colleagues/employees/managers attend a course like this?  Is the fact that JavaFX Script is new and changing a deterrent to attending a course like this, or are there folks (early adopters and CTO types) that would attend because it is new and changing?  Please offer feedback either by submitting a comment to this post, or emailing me at jim.weaver at lat-inc dot com.

Regards,
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications

Red Rubber Ball (Puzzler 2) Results and Sample Solution

Congratulations to Pavel for submitting the first solution to the Red Rubber Ball Puzzler, and the fact that it met the requirements of the problem.  Thanks also to Erik for submitting a solution.  I've actually decided to award both Pavel and Erik a JavaFX Script eBook because Erik used the localDragTranslation attribute of the CanvasMouseEvent (a technique shown in the JavaFX Canvas Tutorial).  Because of this, when clicking and dragging the circle, it doesn't center the circle on the point at which the mouse was clicked (as Pavel's solution does).  Again, both solutions met the requirements, and congratulations to both!

For reference, here's my sample solution:

/*
 * RedRubberBallSolution.fx
 */
 
import javafx.ui.*;
import javafx.ui.canvas.*;

class RedBallModel {
  attribute x:Integer;
  attribute y:Integer;
}

Frame {
  var model = 
    RedBallModel {
      x: 200
      y: 200
    }
  var canvas = 
    Canvas {
      content:
        Circle {
          cx: bind model.x
          cy: bind model.y
          radius: 100
          fill: red
          onMouseDragged: operation(cme: CanvasMouseEvent) {
            model.x += cme.localDragTranslation.x;
            model.y += cme.localDragTranslation.y;
          }
        }
    }
  title: "Red Rubber Ball Solution"
  content:
    BorderPanel {
      center:
        canvas
      top:
        FlowPanel {
          content: [
            Button {
              text: "Reset"
              action:
                operation() {
                  model.x = 200;
                  model.y = 200;
                }
            },
            Button {
              text: "Print"
              action:
                operation() {
                  canvas.print();
                }
            }
          ]
        }
    }
  width: 500
  height: 500
  visible: true
}

By the way, I am trying to submit these puzzlers at different times of the day so that everyone gets a fair chance at some point of actually being awake when one is submitted.  Insomniacs, of course, have a big advantage ;-)

Regards,
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications

JavaFX Puzzler 2 - First Correct Solution Gets Free JavaFX Script eBook

In this post, I'm going to give you a slightly more difficult JavaFX Script related "puzzler".  If you've been following along with this blog, and exploring the resources to which I've been pointing you (hint: especially the JavaFXPad tutorial), you may find this puzzler easy to do.  The first person to post a comment with a correct solution will be given a free JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications eBook (PDF download).  When submitting your answer, be sure to put your correct email address in the  "Email Address: (Not displayed with comment.)" text field on the comment form so that I can contact you with the information to obtain your free eBook.

Printing the Contents of a Canvas Instance

Before I give you the puzzler, I'd like to mention that Andre Torensma pointed out my comment in this blog post about not having built printing capability into the Word Search Puzzle Builder.  Andre asked how that could best be accomplished, so I wrote a quick example that shows how to print the contents of a Canvas instance.  See the screenshot below, and the code listing that follows it:

/*
 * RedRubberBall.fx
 */
 
import javafx.ui.*;
import javafx.ui.canvas.*;

Frame {
  var canvas = 
    Canvas {
      content:
        Circle {
          cx: 200
          cy: 200
          radius: 100
          fill: red
        }
    }
  title: "Red Rubber Ball"
  content:
    BorderPanel {
      center:
        canvas
      top:
        FlowPanel {
          content: [
            Button {
              text: "Print"
              action:
                operation() {
                  canvas.print();
                }
            }
          ]
        }
    }
  width: 500
  height: 500
  visible: true
}

As shown in the listing, the Canvas has an operation named print() that causes what is drawn on it to be printed.  When you click the Print button shown in the screenshot, a standard printer dialog box should appear.  Of course, a JavaFX application invoked with Java Web Start would have to be granted the appropriate permissions to print.

Another thing to point out in this listing is that an instance of the Canvas class is created and assigned to a variable so that it may be referred to later when printing the canvas.  Variable assignments in this manner are considered part of the declarative expression, and don't require a semi-colon at the end.  The scope of the variable named canvas is the block in which it is defined (between the curly braces associated with the Frame object).

As a result of Andre's prompting, I added print functionality to the Word Search Puzzle Builder using the same technique as shown in the excerpt above.  For now I just added a Print option to the Grid menu (no shortcut or toolbar icon yet).  Give it a try if you'd like!

Back to the Puzzler

The objective of the puzzler is to modify the code listing above so that the program provides the following functionality:

• Dragging the circle with a pointing device (e.g. a mouse) causes the circle to move with the pointing device.
• Clicking a button named Reset that is located directly to the left of the Print button (see the screenshot below) causes the red circle to move to its original position (with the center of the circle at 200 pixels on the x axis and 200 pixels on the y axis).

You must use a model class (I named mine RedBallModel) with x and y attributes that hold the current location of the circle.  You must use binding to cause the circle to appear at the coordinates in the model.  Clicking the Reset button, and dragging the pointing device, directly change the values in the model.

Please submit your solution in the form of a comment to this post.  I will examine the code to make sure that it meets the requirements above, and then cut and paste the code into JavaFXPad to verify that it works per the requirements.  Even if you're not the first to respond, go ahead and submit a solution anyway, as it may be the case that the entries submitted prior to yours don't meet the requirements stated above.

Good luck!
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications

Scribbling on PlanetJFX

In a previous post, I gave you an introduction to the 2D graphics capabilities of JavaFX Script.  I also directed you to the JavaFX Canvas Tutorial, which is an excellent resource for understanding and experimenting with JavaFX Script 2D graphics and the Canvas widget.  In this post, I'd like you to play with a simple example program on PlanetJFX called Scribble, and then examine its short code listing.  You can do this easily by pasting the code from the PlanetJFX page referenced above into JavaFXPad (see previous posts for installing/invoking JavaFXPad).  Here's my salute to The Hitchhiker's Guide to the Galaxy using Scribble:

As you look at the source code, it will be helpful to have the JavaFX Canvas tutorial available.  This is because you'll find, for example, the Polyline class in the Shapes section, the Group class in the Groups section, the CompositeNode class in the User Defined Graphics Objects section, and the CanvasMouseEvents class in the Input Events section.  By the way, this line of code from the example requires some additional explanation:

var: self

This creates a reference named self to the object being literally defined (in this case a Group object).  You'll noticed that it is used later in the program to reference the content attribute of the Group instance:

insert polyline as last into self.content;

By the way, ScribbleRect.fx was originated by Sven Drieling, and developed with some help from others in the PlanetJFX community.

Regards,
Jim Weaver
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications