We have moved!

Rather than using Blogger.com for our Blogs, we have decided to setup an external website that will be a central resource for everything we do.

The advantage to this approach is that this increases the amount of traffic, for technical blogs, but more importantly to advertise our products when released.

Please visit us at http://SpikyOrange.co.uk, we hope to increase our content for software developers, including videos on YouTube and gems of information through Twitter.

Thanks for visiting!

Rob.

Appcelerator Titanium - Installation issues on Ubuntu 10.04 (Lucid Lynx)

The Titanium product promises desktop and mobile development, using HTML, CSS and Javascript, to Windows, Mac, Linux, Android, iPhone and soon Blackberry.


This is an impressive goal, but can it really work?

My first step was to install the product, which unfortunately wasn't as straight forward as I would have liked.  This blog entry is hopefully my first of many, on Titanium, purely to document the steps I took to get it running on Ubuntu.  This blog does not detail the full setup procedure, instead, I show what I had to do to get it working after I had completed their installation instructions (follow link, then select downloads).

When trying to run Titanium I received the error "symbol lookup error: /usr/lib/libgdk-x11-2.0.so.0: undefined symbol: g_malloc_n".  To fix that, I had to type...

cd /home/rob/.titanium/runtime

rm libgobject-2.0*
rm libglib-2.0*
rm libgio-2.0*
rm libgthread-2.0*

It would seem that it didn't like trying to use the Java open JDK, so I typed

sudo aptitude remove openjdk-6-jre icedtea6-plugin

To change from Open JDK to Sun JDK...

sudo aptitude install sun-java6-jre sun-java6-jdk sun-java6-plugin sun-java6-fonts

After all of this, Titanium then reported that it couldn't create a new project, so I changed the use of Android 8 to Android 4 (within the 'android' tool that enables you to specify the API's to install) and then...

gedit ~/.profile

Note that the 'android-4' mentioned in the path was 'android-8' but failed to work...

PATH=”/home/rob/android-sdk-linux_x86/tools:$PATH”
PATH=”/home/rob/android-sdk-linux_x86/platforms/android-4/tools:$PATH"
export PATH

I did have a timeout error launching the Android emulator, when this happened I launched the simulator again and then it worked.

I still receive an error '[ERROR] /home/rob/android-sdk-linux_x86/tools/apkbuilder' which I have yet to resolve, however, it doesn't seem to stop the tool from running!

 


My attempt of installing on the Mac also failed - I currently can't launch the iPhone simulator, but that's for another blog entry (once I've fixed it!).

Learning Game Programming - XNA #1

My first attempt of using Microsoft XNA - I plan to create a game eventually, but the first stage is to experiment with the Framework. I coded it using C#, one sprite (increasing to 100 gradually), it uses scaling, rotation and movement.

I'm reading Learning XNA 3.0 from O'Reilly at the moment, I have two other XNA books too. This is simply for a hobby, nothing professional at this stage is required. I would like to finally get the 'game' I write on to the XBOX 360 as a multiplayer game (Split Screen) and eventually over XBOX live.

100 x sprites (512 x 512 resolution) being dynamically resized and rotated maintains 60 FPS! Once FRAPS starts recording for capturing on to Youtube it goes down to 30 FPS.

How to copy music and photos from your iPhone to the Mac without iTunes

I needed to sync my iPhone to my Mac, but previously it was synced to my Windows machine through iTunes. No matter what I tried, I couldn't find a way to transfer the files from the iPhone to the Mac through iTunes... Complete madness!!

If you search on-line, you will find plenty of software that promises to solve this for you, but I was lucky enough to stumble across a couple of utilities that done what I wanted....

One good entry is on Yahoo but I found two independent free sources of software before I stumbled across that site, they are:

Senuti - at least it's a 30 day trial if you just need to copy all of your music quickly

'Image Capture' (visit your Macs application folder to load it), it will copy the photos from your iphone to a directory of your choice!

Now I can sync everything from my Mac back to the iPhone without loosing anything... I'm not sure about the applications (I've used iTunes to right-click on the iPhone and chose 'transfer purchases')

I hope that helps!

Professional Webinar Training at a nominal fee?!

Hi all, I've been looking around for on-line training webinars of professional quality, the closest that I've found are sites such as Parleys.com - but they aren't really training sessions per say. That has made me start to wonder whether there is a market for me to do my own professional webinars at a nominal fee - say £10 per session! My goal would be to set a price that permits individuals to purchase training sessions, simply by reducing the cost to the minimum but increasing the number of people in the webcast. I've had the luxury of being to Learning-Tree courses, costing my employer £3,000+. As an individual, I would love to go again, but alas my employer is not likely to send me any time soon, I also personally don't have that sort of money to spend! I would love to hear your thoughts, in particular it would be great if you could spend some time completing this quick survey? I do appreciate that you might want to just reply here instead, either way, your feedback would be very much appreciated. Regards, Rob - SpikyOrange.

JAX-RS and the Netbeans code-generation

I've posted to the Netbeans forum about my experiences with the JAX-RS code-generation, a copy is enclosed below:

Hi,

As per my last post, I'm playing with the JAX-RS code-generation from within Netbeans and I have some questions / concerns about the code it generates.

Server

One entity results in 3 classes - 1) a POJO to match the database entity with JPA annotations, I'll call this the domain object. 2) a Resource class that is basically the JAX-RS service definition using JAX-RS annotations (I'll refer to this as the controller) and 3) A converter class that uses JAXB annotations to define how to marshall/un-marshall the data.

Part of me likes what's generated, but, another part of me doesn't understand why so much code has to be generated _if_ we are going to program by convention instead, i.e. if the entity is called User and one field is userName, then it makes sense that the domain object is called User, has one field called getUsername and this same class could be annotated with the JAXB annotations? It makes sense that the services are in a separate class - but if it's a straight pass-through of data for CRUD operations, then an annotation could be added to the POJO and then one class has all the annotations (admittedly this is for prototyping or simple solutions)?

On the opposite side of the coin, I like the separation, however, I'd almost like it separated even more! I'm thinking about the fact that the UserResource (I see this as a controller) should delegate through to some sort of re-usable manager, the manager returns back the data for the controller to do what it sees fit. Lets say I add an RMI server, I want the controllers in that to call my re-usable / common manager code, but thats not possible with the code that has been generated by Netbeans.

The other reason why I want the resources to delegate to a manager is that I might add 5 new fields to an entity and as a result re-generate the entity classes, restful classes and client-side stubs. Currently the controllers will be overwritten with the new version and any custom code is replaced. One solution would be to enable the programmer to mark blocks as protected, so that generated code preserves what's entered? Does anyone have a workaround for this?

Service parameters - I don't know whether I like the fact that each resource is given the start, max, expand level and query parameters. For example, I might want to return data specific to the user that's logged in, but if the client can influence the query run, that sounds dangerous? I certainly want the default to be customisable, i.e. 100 results for some entities.

Auto serialisation - Are the Converters really necessary? I previously experimented with Spring and used the XStream API to take an object graph and marshall/un-marshall it to XML. Can't the framework do this generically rather than a converter class per entity. The marshaller could explode or collapse the references, i.e. if I return an XML object graph of a JAVA object graph, it returns an element / attribute for each field, but if the field points to another entity, it can either collapse it include the URL reference, or serialise the child object inline in the XML for convenience (or a hybrid of both).

Client

An entity with two references to the same entity - generates bad code - I noticed that my Profile has two Address, named homeAddress and businessAddress, but in the Profile.js file it does not have two variables as homeAddress and businessAddress, instead it has two attributes of the same name 'address'. This causes hiding of values and means one of the values will not be stored correctly.

As JSON or as XML - Although the domain objects in the client have methods to get attributes, it appears that it always defaults to JSON, but sometimes it's actually nice to say I want the verbose XML version instead, especially when some of the GUI frameworks might only have XML support.

Why an object - It would be nice if there was an alternative option to generating object versions of the domain objects, i.e. EXT-JS doesn't know about the domain objects and will just use the JSON or XML results, so using the generated domain objects is very nice for auto-loading child objects, but if I could ask for the raw XML/JSON instead and the server exploding references out to the actual objects, it would be simpler (but not pure REST I agree!).

A DAO interface - The client generated code appears to really help rapidly get some data from the server without writing any code (always a good thing), but I think it needs the ability to have the equivallent of a Java Interface, with CRUD style operations exposed and a JAX-RS implementation as default. Then I can easily add a switch before that to go to Google Gears for example if installed, whereas at the moment I would have to insert the code inside each entity.

So my suggestions, in the wizard

- Ask whether a simple CRUD solution is required, if yes, annotate the POJO instead of creating a Resource class for each entity
- Ask whether to introduce a manager / interface to delegate to
- Enable what parameters are used per entity (and these settings to be remembered across code-generations), plus default values (i.e. max results to return).
- An option to serialise using convention rather than code
- provide an option whereby the javascript variable names reflect the field names (homeAddress) instead of the type (address).
- Explode references to resources to inline resource (i.e. becomes xxx etc.
- Generate client DAO pattern to help with Google Gears / other client integrations.

I'd love to hear feedback on my initial thoughts, particularly any architectural suggestions to assist with making these things even more reusable.

JavaFX on hold...

For anyone that has been following my posts related to Java FX, I am currently putting my efforts into learning Ext-JS as I am finding Java FX a little immature at the moment.

My reasons are:

• I see differences in rendering between my Mac and PC
• Creating forms manually is much more painful than I would like
• It still feels to early to be using Java FX until proper tooling is available
• Concerns about whether Java FX will be supported once Oracle complete the purchase of Sun
• Java FX seems better at multimedia style websites rather than functional applications (in my opinion), i.e. Ext-JS provides what appears to be simpler form handling and validation.

I hope to return to the Java FX training in the future, when exactly - I'm not sure.

In the meantime, look out for blogs on JAX-RS, JPA and EXT-JS. I played briefly with Restful services in Spring v3, then thought it was a little painful and used the Netbeans wizards for generating my domain objects and services. It appears to look good so-far, but I'm sure I'm making things more difficult than they need to be.

Linux - Disk usage

The amount of times I have to Google for the Linux command to calculate the amount of disk-free space from the present working directory, I decided to blog it so others can share in it too!

Simply type

du -ks directory

Where du = Directory Usage

-k = Use units of kb (1024 bytes) for size

s = Display summary only

directory = Is the directory to start reporting sizes, or if not provided it defaults to the current directory.

JavaFX Week 7 (Animation)

The signer certificate has expired

When trying to run the sample application CustomNode_animation_colliding_balls_3steps I noticed that it would not run due to the following error

init: 
deps-jar:
keytool error: java.lang.Exception: Key pair not generated, alias  already exists
Warning: The signer certificate has expired.
compile:
jar:
standard-run:
java.lang.NoSuchMethodException: collidingballs.MotionBall_3.javafx$run$(com.sun.javafx.runtime.sequence.Sequence)
        at java.lang.Class.getMethod(Class.java:1581)
        at com.sun.javafx.runtime.Entry.start(Entry.java:63)
        at com.sun.javafx.runtime.Main.main(Main.java:80)
browser-run:
jws-run:
midp-run:
run:
BUILD SUCCESSFUL (total time: 3 seconds)

To fix this, I simply went to the project properties, selected the 'application' tab, then disabled the 'self signed jar' option. I guess another project already has stored a certificate that conflicts with this demo.

Adding a little debug on-screen

I was asked whether we could output some debug quickly to see the values of the x position offset (xoff), scale and xflip, after a little consideration I added a VBox to provide a simple layout manager and then added three labels that were bound to those values. Hey presto, simple on-screen debug.

import javafx.ext.swing.SwingLabel;

import javafx.scene.layout.VBox;

.
.
VBox {
 content:[
  SwingLabel {
   text: bind "Xoff = {xoff}"
   width:400
  },
  SwingLabel {
   text: bind "Scale = {scale}"
   width:400
  },
  SwingLabel {
   text: bind "xflip = {xflip}"
   width:400
  }
 ]
}
.
.

Flipping Sharks!

It took a while to work out what timeline was required to move the sharks form the top-left of the screen to the bottom-right, to include the zoom and flipping of the Sharks.

I used three variables that I bound at different locations in the scene graph (actually I had help on this one by collegues at work).

var scale = 0.3;
var xoff = 0;
var xflip = 1.0;

My timeline was always pretty much right, but the key part is in the next section

var st = Timeline {
    keyFrames: [
        at(0s) {
        scale => .3;
        xoff => 0;
        xflip => 1.0
        },
        at(2s) {
        scale => 1.0 tween Interpolator.LINEAR;
        xoff => 300 tween Interpolator.LINEAR;
        xflip => 1.0
        },
        at(2.5s) {
        scale => 1.0 tween Interpolator.LINEAR;
        xoff => 350;
        xflip => -1.0 tween Interpolator.EASEBOTH;
        },
        at(4s) {
        scale => 0.3;
        xoff => 0;
        xflip => -1.0
        },
        at(5s) {
        scale => 0.3;
        xoff => 0;
        xflip => 1.0
        }
    ],
    autoReverse: false,
    repeatCount: Timeline.INDEFINITE
};

The Sharks ImageView was not happy having a transform applied to scale the sharks position and flipping in one go, so Chris at work came up with this option to have a sequence of transformations that are applied one after the other.

var shark = ImageView {
.
. 
    transforms: bind [
      Transform.scale(scale,scale),
      Transform.scale(xflip,1,theImage.width/2,0)
      ]
    translateX: bind xoff
.
. 
};

Learning EJB 3

Recently I have been trying to learn a mix of Spring Restful web-services and IBATIS, but in this journey I started to get a little frustrated with them both. I admit this is probably due to my lack of knowledge with both of those frameworks, but recently I discovered that I purchased an O'Reilly book over 12 months ago on EJB 3 and thought "I wonder if that's any better". Certainly if you read the hype on Spring you will be convinced that EJB is heavy weight, complicated and typically the wrong option.

I've only read about four chapters in the book, but so far I must admit it's cleaner and simpler than I expected. You could argue that Spring has many features that would be advantageous, such as dependency injection, but in my opinion the level of dependency injection provided within EJB 3 is probably sufficient for my needs. Spring seems to be growing almost daily and I started to feel like I was drowning rather than at least treading water - but I haven't given up. I successfully managed to use the new Spring annotations to expose Restful web-services, plus started to integrate with IBATIS, but I was getting increasingly concerned about parts of my code getting more and more coupled to Spring.

This past week I have been looking at restructuring my code, to enable me to support different frameworks (Spring and EJB for exposing business methods over the network from a client and various persistence technologies in the server).

Below is a diagram that sums up where I am at the moment.



I'll try to explain in words how to interpret my class diagram - but bear in mind, some of the relationships are hiding what really goes on behind the scenes, but should give you a general idea.

First, if you're new to EJB 3 like me, it's worth pointing out to you that you can pretty much develop your business logic using plain old Java objects (POJOs) and then add Java 5 annotations to 'decorate' them with EJB 3 features, for example, I have annotated my UserStatelessSessionBean with two EJB 3 annotations, EndPoint and Stateless. Those annotations will indicate that a SOAP based web-service should be used to access the service and that the bean is not expected to hold state between requests, the latter enables many requests to share the same object and increase scalability.

The MyStatefulSessionBean used three annotations Local indicates that certain methods can be invoked from within the same JVM without the overhead of remote method calls, dramatically increasing performance - but this does not help you if you want to access the methods from a client application. In this scenario I have used the Remote annotation to indicate that the methods will be accessible via JAX-RPC style web service requests. The Stateful annotation indicates that this bean is expected to hold state across invocations and therefore it can't be shared between sessions.

From my understanding, Stateful session beans are closely linked to fine-grained services, i.e. you might invoke the service with 20 messages/methods to do one job. Whereas Stateless session beans are closely linked to course-grained services, i.e. you might invoke only one method to do one job (use-case). I have yet to throw myself into this to fully appreciate one model over the other, but my suspicion is that scaleability is best achieved by being as stateless as possible. My rational for this is to consider some large application like facebook, if you have a simple course-grained service that says something like postMessage(myUserId, targetUserId, theMessage), then the message has everything it needs to service the request and could therefore be sent to any server in a cluster, enabling load balancing and all those wonderful things to work best. If I used a stateful session bean, either the state gets replicated across the cluster which must be slow, or you are restricted to talking to the originating server to complete your session.

My aim in this class diagram is to show flexibility and therefore re-use. Firstly I have a GUI that talks via an interface to 'do things', then I have an implementation of that interface that uses EJB3 and another that uses Spring. This means that if I find one to be more reliable, faster, better suited for intranet/public internet access, I can easily swap the client to server communications very quickly, without affecting any GUI code!

The same can be said on the server, The EJB session beans and Spring web-services are controllers that I have made as dumb as possible. The controllers simply delegate their work to a Manager class that does all the business logic. This means I can add say a CORBA controller, or perhaps implement the Google protocol buffers and re-use all the manager code as-is. Obviously if I add some features in the server, I might want to add the option in the GUI to use that new service too.

Okay, so far this all sounds dandy, but is it really likely that I want to swap between Spring or EJB or Google protocol buffers? Well, perhaps not, but the option would be nice wouldn't it?! There is another good reason for doing this though, perhaps you can expose these APIs to enable other developers to add value to your application, the more API's you expose, the more chance you have of increasing developers to your API.

The last part of my class diagram is to show that I've done the same thing with the Data Access Object, I can therefore implement the DAO using EJB3 JPA or IBATIS, Hibernate or pure JDBC.

The Domain objects can remain POJOs in most (if not all) cases, therefore my intention is to re-use the domain objects in the client tier and server tier.

I guess at some point I will have a sample application to prove my thoughts, but in the meantime, if anyone has any comments then I would be very happy to learn from you!

Many thanks
Rob.

JavaFX Week 6 (GUI Week 3)

I have tried some of the sample applications, I remain unimpressed with the performance on the Mac using the FireFox browser.

Three levels of skinning

• CSS Theme - Most accessible method and will accommodate 60-80% of use, although Java FX 1.2 is not fully CSS featured. A very basic example of CSS use can be found here http://javafx.com/samples/CSSFun/index.html



• FXD for Skin - Use the Java FX production suite to export artifacts from Illustrator or Photoshop.



• Custom Skin - Replacement of a skin for a button for example by using your own image for the button, but you're responsible for the tedious details, such as overriding functions to provide preferred size information.

The default 'skin' in JavaFX 1.2 is called Caspian, this site covers the decisions about the colour schemes used and why http://fxexperience.com/2009/06/caspian-skin/

Charting - Six types in Java FX 1.2

Area Chart
Bar Chart
Bubble Charts
Line Charts
Pie Charts
Scatter Charts

For more information refer to http://pleasingsoftware.blogspot.com/2009/06/this-is-test.html

Internationalisation - JavaFX is very similar to Java in the way that it handles I18N, but instead of using a .properties file it expects a .fxproperties file. All message keys and values are quoted, i.e.

"NB_Title" = "JavaFX 用 NetBeans IDE"

To reference one of the properties, it's as simple as using two hashes followed by the key of the property, i.e.

Locale.setDefault(new Locale("en", "US"));
.
.
{
    title :  ##"NB_TITLE"
}

For a full explanation see the following link

JavaFX Week 4 homework

I enjoyed week 4 of the JavaPassion JavaFX tutorial, the only problem I experienced was that the Gaussian effect didn't seem to work as expected. The flame was meant to have three colours, but as soon as I add the Gaussian blur it seems to kill the colours.



The preview function in Netbeans showed it okay (left third of the screenshot), but at runtime the colours completely dissapear (see right third of the screenshot).

I didn't want to post the full code, but hopefully enough is visible in the screenshot to show you what I entered for the effect - perhaps someone can see what's wrong?

Thank you to Dieter Sabolewski, who has pointed out that the code worked fine on a Windows machine, unlike my Mac Book.

My PC has Windows 7 RC as operating system. Java is the newest release for
Windows.
The code runs here fine. I tested with your values, also with different
values for time and glow. The glowing can be seen perfectly.

Some issues to be noticed:

Obviously the JDK for fx and the runtime do still have a lot of
malfunctions. The code shows you, that I had to outcomment the 'stroke'
command to render the 'linearGradient' of the rectangle. I played a little
around and I can confirm, that the linearGradient of the rectangle renders
very dependent from the resized stage. This seams from my point of view be a
problem of the data binding, resp. the continiously update of that.

JavaFX Week 3.4 Binding

I almost missed the task of doing the binding assignment, because I got so wrapped up in the Asyncronous resources, then got interested in the scene-graph topics, but finally I got around to completing it.

It's worth highlighting the fact, that binding to an object will mean that any changes to the attributes within the object, will cause a new object to be instantiated. This was explained in the JavaPassion course, the only addition I would make is that you can verify this easier by adding the hashcode to the details being output (for those that don't know, the hashcode by default will contain an object reference that will be unique for each Address object - you can override this to be whatever you like, but we are relying on it to compare object references to prove that the binding created a new object instance).

 // Define Address class.
class Address {
     var street: String;
     var city: String;
     var state: String;
     var zip: String;
}

var myStreet = "1 Main Street";
var myCity = "Santa Clara";
var myState = "CA";
var myZip = "95050";

// Bind address variable to Address object
def address = bind Address {
     street: myStreet;
     city: myCity;
     state: myState;
     zip: myZip;
};

println("----address.street before myStreet is changed= {address.street} 
hash:{address.hashCode()}"); // 1 Main Street

// By changing the value of myStreet, the street variable inside
// the address object is affected. Note that changing the value 
// of myStreet actually causes a new Address object to be
// created and then re-assigned to the address variable.
myStreet = "100 Maple Street";
println("----address.street after myStreet is changed 
= {address.street}  hash:{address.hashCode()}"); 

Now if you change the binding above to this...

def address = bind Address {
     street: myStreet;
     city: myCity;
     state: myState;
     zip: myZip;
};

Then you will notice that the two address hashcodes are identical - proving now that JavaFX did not have the overhead of instantiating a new object, but simply changed the street attribute (most likely what you intended).

Bind for

I was impressed with the binding ability against sequences, I add an object to the sequence seq1 and the sequence seq2 was updated to reflect the new value, but doubled as per the expression in the bind - wow!

var seq1 = [1..5];

// Bind to for expression
def seq2 = bind for (item in seq1) item*2;

printSeqs();

insert 10 into seq1;

printSeqs();

function printSeqs() {
     println("----First Sequence:");
     for (i in seq1){println(i);}
     println("----Second Sequence:");
     for (i in seq2){println(i);}
}

binding_to_if contains a bit of code that was a little odd to read at first

var primeOrNot = bind if (Sequences.indexOf(primeNumbers, curr) == -1) 
                     "not a prime number"
                      else "prime number";

I completely miss-read the line, I read it as 'from the sequence, find the index of...', but it actually reads as 'Using the indexof utility method from the Sequences static method, find the first object in the primeNumbers sequence that matches the value curr'. Here's the JavaFX doc for it:


Searches the specified sequence for an object with the same value. The objects are compared using the method equals(). If the sequence is sorted, binarySearch should be used instead. If the sequence contains multiple elements equal to the specified object, the first occurence in the sequence will be returned. The method nextIndexOf() can be used in consecutive calls to iterate through all occurences of a specified object.

import javafx.util.Sequences;

var primeNumbers = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29];
var curr = 1;

// Bind to if expression
var primeOrNot = bind if (Sequences.indexOf(primeNumbers, curr) == -1) 
                      "not a prime number"
                      else "prime number";
println("----{curr} is {primeOrNot}");

curr = 6;
println("----{curr} is {primeOrNot}");

curr = 3;
println("----{curr} is {primeOrNot}");

JavaFX Week 3.3 - Good video tutorials / overviews

I followed a link to Parleys.com and found these JavaFX videos that I would recommend you look as an overview of what's possible in JavaFX.

Introduction to JavaFX - Jim Weaver gives a high-level overview of JavaFX, including lots of code snippets. This is a little slow paced and uses the command-line compiler - I assume this is before the Netbeans plugin was available. Covers closures too, which is in my opinion 'advanced' rather than an introduction topic. Closures are 'the ability to access variables in the context that the function was created within'. This video is worth watching to understand binding, including bi-directional binding and triggers - useful for form-based user interfaces for example.

JavaFX SDK - Danny Coward (excellent presenter) shows exporting from Photoshop and some good demonstrations of JavaFX in use (includes playing media with emphasis of deploying the same app on multiple devices, i.e. mobile devices and desktop, integration between JavaFX and Javascript in the browser).

Overview about the API - Richard Bair and Martin Brehovsky cover the API, primative types, sequences, operators, flow control, binding, object literals, scene graphs, animations, transitions. I recommend this video the most.

An interview with the JavaFX team - The Java Posse interviews the JavaFX team.

• What is JavaFX?


• Why a new language?


• What happened with the JavaFX launch? (There was a problem with the launch)


• How should people evaluate JavaFX?


• What new features does JavaFX bring to UI developers?


• What does binding allows us to do?


• What is the JavaFX runtime size?


• How should you prepare your libraries for use in JavaFX


• How to develop new JavaFX components


• Any plans to use JavaFX script in non UI domains (i.e. server)


• Is there a recommended client/server communications API


• Where's the interfactive JavaFX shell


• Any plans to support scene graph for other JVM languages


• What other technologies will interact with the JavaFX language


• Any plans to create a JavaFX component market place


• Will there be a JSR for JavaFX?


• Why should Flex/Silverlight developers want to look / change to JavaFX


• What about the Applet experience


• What about JavaFX tools


• Support from Eclipse?


• Anything else you want to share with

Enjoy!

Week 3.2 Knowledge Experiment

Given my current limited knowledge of JavaFX, I thought it would be an interesting experiment to try and create a scene graph that contained a circle and rectangle, then on a timeline zoom them in and out repeatedly. Here's a screenshot of the end result, okay, it's nothing special and I will not win any awards for this 'experiment', but it shows you how quickly a newbie can pick up JavaFX and run with it!

You might even notice that I have some transparency involved!



So when I was thinking about doing this, my first thoughts were "hmm, I need a Thread that would periodically adjust some attributes and then cause the graph to redraw using the new values".

Almost immediately afterwards I remembered that in JavaFX you would use binding to keep the user interface in sync with some data / model. So all I needed to do is find out how to add things to a scene graph.

I must point out here, I did not use any javadoc, nor read an article, I simply used the JavaFX palette in NetBeans, then filled in the blanks. In some places I needed slightly more information, so I used the code-completion feature (ctrl+space) to learn what attributes were available... Yes, this was all guess-work.

Here's the code

package week2blog;

import javafx.scene.Scene;
import javafx.scene.Group;
import javafx.scene.shape.Circle;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.animation.Timeline;
import javafx.animation.KeyFrame;
import javafx.animation.Interpolator;
import javafx.stage.Stage;

var sc : Number;

var tl : Timeline = Timeline {
  repeatCount: Timeline.INDEFINITE
  keyFrames : [
    KeyFrame {
      time : 1s
      canSkip : true
      values : [sc => 0.0 tween Interpolator.EASEBOTH]},
    KeyFrame {
      time: 2s
      values : [sc => 10.0 tween Interpolator.EASEBOTH]},
    KeyFrame {
      time: 5s,
      values : [sc => 0.0 tween Interpolator.EASEBOTH]}
  ]
};

def scene : Scene = Scene {
  width: 600,
  height: 600,
  fill: Color.LIGHTGREEN,
  content: [
    Group {
      content: [
        Circle {
          centerX: 100, centerY: 100
          radius: 40
          fill: Color.BLACK
          scaleX: bind sc
          scaleY: bind sc
        },
        Rectangle {
          x: 100
          translateX: sc  * 50
          y: 300
          width: 140, height: 90
          fill: Color.PURPLE
          scaleX: bind sc
          scaleY: bind sc
          opacity: .5
//          effect:Shadow {
//              color: Color.BLACK
//              radius: 15
//            }
        }
      ]
    }
  ]
}

Stage {
  title : "Experiment"
  scene: scene
}

tl.playFromStart();

You'll see that I discovered timeline and keyframe objects that I could use to declaratively build up my animation. The timeline is literally as it sounds - a time line, it does nothing on its own, but you add timing information into it and what you want variables to be at that time! Imagine if I said that I want my rectangle to be at the co-ordinate 0,0 at the start of the animation and 10 seconds later to be at 100,100... It would be pretty dull if it jumped from 0,0 (at the start of the animation) to 100,100 (10 seconds later), so you specify an Interpolator to say how it changes over time - tweening I believe it's called.

The obvious interpolator is the linear one, it will simply adjust the attribute from 0,0 to 100,100 linearly over 10 seconds, so in 5 seconds for example, you would be half way through the animation, meaning the values would be 50,50.

Seconds - Position
0 - 0,0 (start)
1 - 10,10
2 - 20,20
3 - 30,30
4 - 40,40
5 - 50,50
6 - 60,60
7 - 70,70
8 - 80,80
9  - 90,90
10 - 100,100

There appear to be many Interpolators, I chose the EASEBOTH, which evidently starts slowly, increasing speed and then slows back down again before completing.

One thing that was obvious, I tried to add a shadow effect and this was very slow on my MacBook - so go careful on those special effects; this is an old machine so I would expect it to look pretty good on a newer model. At the very least, give your users the option to opt out of any demanding effects.

In some cases you can consider using the cache option - this will enable re-rendering of portions of the scene graph to be quicker, but it will only cache the graphic at a specific size, or effect, so I guess you would use this for things that are statically placed, but require some effects (i.e. a button with a shadow and glow effect). You will need to trade off memory v speed if you use any caching.

As you can see, the code is pretty small - so I think I am going to like JavaFX!

Rob.

JavaFX Week 3.1 New knowledge (and broken examples)

I would like to say a big thank you to all those people on the JavaPassion, JavaPosse and Sun JavaFX forums for posting their feedback on their respective sites. It was ultra-cool to get some comments from Tor Norbe from the JavaPosse who I have been listening to for years - with some valuable feedback (see my comments on the previous blog for the link).

Additionally a nod to Russell Miles, an experienced developer and author of many books, but more importantly a friend, he has blogged a response to my 'first impressions of JavaFX' post. He didn't agree with all my points, but I would like to put him straight on one thing - JavaFX is statically typed, evidence is here from the horses mouth...

Source: Learning JavaFX script PDF resource (By Robert Eckstein and the Authors of the JavaFX Programming Language Reference, July 2007) "The JavaFX Script programming language (hereinafter referred to as JavaFX) is a declarative, statically typed scripting language from Sun Microsystems, Inc."

My blog today covers some interesting points from that documentation...

JavaFX is primitive

(Primitive types)
The JavaFX programming language provides only four primitive types: String, Boolean, Number, and Integer. Note that, unlike the Java programming language, primitives are written with an initial capital letter! So I guess that's something along these lines

JavaFX Java equivalent 
String java.lang.String 
Boolean boolean
Number floats and doubles
Integer byte,short, int, long

But you can fully qualify the Java type to get a Java Boolean, if that's what you really, really want.

// var b : Boolean = null; <-- does not work
var b: java.lang.Boolean = null;

The feedback I received on the JavaPosse was that using nulls is BAD BAD BAD, it makes some sense when you are using objects that map on to database objects - but even that apparently is bad practice, a boolean that's null to me implies 'not known', so I think it's okay - the user might not have specified a value, so you don't want to assume 'false' or 'true' - because they will have specific meanings. I guess I might need to re-evaluate my thinking a bit, but I like my user-interfaces to not force the user to enter all the fields - to the extent that nulls are used where the user has not specified an intentional value.

In my last post I was struggling to understand why Boolean in JavaFX can't be null, but it now makes more sense, knowing that Boolean is mapped to a primative boolean. Why does that make more sense?... Well, lets put our Java hat back on for a second...

public class JavaCode {

    public boolean getPrimativeBoolean() {
        return null; // WILL NOT COMPILE
    }
    
    public Boolean getObjectBoolean() {
        return null; // THIS IS OKAY
    }
}

So there we go, the answer is Boolean in JavaFX is a primitive boolean in Java, and because Java primitives can't hold a null, then you can't do it in JavaFX either. So I still need a solution to hold null values, but at least I understand why I can't using Boolean in JavaFX!

Of course I can simply wrap a primitive boolean in some simple class, but I am worried that I might cause some problems when I want to introduce binding later on.. i.e. I try to bind to my wrapper object, but the wrapper object doesn't actually change.

Oh, and that explains why String could be set to null, because in Java there is no primitive String - only the object based String. See, it all makes sense now ;-)

But, then they mention cardinality operators - take a look at this...

var variableName [: typeName] [? | + | *] [= initializer]; 
Operator Meaning 
? Optional (For example, it can be null.) 
+ One or more 
* Zero or more 

So, now it sounds like I can set my Booleans to be nullable?

var myBool : Boolean? = null; 
var myBool : String ? = null;

Hmm, well neither of those work for me! Netbeans says "Sorry, I was trying to understand a qualified identifier but I got confused when I saw '?'", bless - how honest! Maybe it's because I'm reading a PDF dated back to July 2007 and perhaps the language spec has changed since. Hopefully I will catch up with this a little more later.

Multi-line Strings
Unlike Java you can create a String over multiple lines...

var s = "This 
         contains 
         new lines"; 

Sequences (again)
In one of my posts I said that it would be nice to create a new sequence based on the 'values' of another sequence - rather than rely on the index numbers. Well, you can - and very nicely too...

"If some of the expressions inside the square brackets look odd, don't worry. They are actually Xquery-Update (similar
to XPath) predicates. In this case, the period inside the brackets does not refer to an index but instead to the value
of the index. JavaFX technology will test each one in the array until the expression is true, then apply the insert."

var x = [1,2,93,55]; 
insert 10 after x[. == 93];        // yields [1,2,93,10,55] 

But that does not work for me in Netbeans "Sorry, I was trying to understand an expression but I got confused when I saw '.'." I am starting to get the feeling that either I don't have the latest version of Netbeans, or the plug-ins are out-of-date.

These examples do not work for me either:

// insert into weekdays after weekdays[. == 3];
// var a:Integer* = select n*n from n in [1..10]; 
// var a:Integer* = select n*n from n in [1..10] where (n%2 == 0); 
// var a:Integer* = select n*m from n in [1..4], m in [100,200] where (n%2 == 0); 

I did find some combinations that worked and that I was comfortable with

var days=["Mon","Tue","Wed","Thu","Fri","Sat","Sun"];
var weekdays = days[0..5];
var daysStartingWithT = days[p | p.startsWith("T")];
var mixedUp = [ days[p | p.startsWith("S")], days [p | p.startsWith("T")] ];
for (day in mixedUp) {
    println(day);
}

Results in

Sat
Sun
Tue
Thu

Async - 'do'
Since my last blog covered asynchronous subjects, I found the following code block impressive - but alas, once more, I can't get it to run, it does not recognize 'do', I can't imagine that they have taken something so useful out. Perhaps someone can tell me what I am missing? :-(

// in the AWT Event Dispatch Thread (EDT) 
var result = new StringBuffer(); 
do { 
    // now in a background thread 
     var url = new URL("http://www.foo.com/abc.xml"); 
     var is = url.openStream(); 
     var reader = new BufferedReader(new InputStreamReader(is)); 
     var line; 
     while (true) { 
          line = reader.readLine(); 
          if (line == null) { 
               break; 
          } 
          result.append(line); 
          result.append("\n"); 
     } 
} 
// now back in the EDT 
System.out.println("result = {result}"); 

Does anyone know where I can get a PDF that contains all of the JavaFX language specification - I really need something up to date for the train ;-)

JavaFX Week 3 - Async

The JavaPassion JavaFX slides this week are mostly a repeat of the binding slides previously seen, so it felt like a quick recap - which is always welcome! The resources were a very interesting read, in summary they were:

Background tasks in JavaFX - A good article on binding variables to the user interface and discusses the fact JavaFX1.2 is single-threaded and how to deal with writing to variables from a background thread.  One comment highlights a bug in JavaFX 1.2, where the percentDone from a Task is returning 0..100 instead of 0..1 - something to bear in mind.

JavaFX 1.2 Async blog by Baechul - Well worth reading, although it might be a bit heavy for a newbie to JavaFX, especially if they haven't done Java before. I've created a class diagram that acts as a summary of this blog because I found it so useful as an overview...



And a version with comments (but I'm not convinced that they will be readable)...



Basically there seems to be some rules to follow, they seem similar to Swing


(Thank you philho for correcting my post in your comments!)

• You must update the user interface components from the EDT (event dispatch thread)


• User interface stuff happens on the EDT, so you can use the javafx.lang.FX.deferAction class to post actions to the UI thread (Presumaly this is similar to SwingUtilities.invokeLater).


• Typically you implement the RunnableFuture interface in one class, then extend JavaTaskBase in another class.  The JavaTaskBase class has a create method that you override to create your RunnableFuture instance.

Jim Weavers JavaFX Blog - shows an example where you can start multiple threads and cancel them, with a user interface showing the progress of each thread.

What seems very clean is that the JavaFX API also uses the thread classes identified above, so for example,HttpRequest extends JavaTaskBase.  Some user interface controls take advantage of this, notibly the ProgressBar integrates nicely with the JavaTaskBase class.  This means that as data is transferred using the HttpRequest object, the ProgressBar can be set up to automatically update to show the progress!



Interestingly you are limited to eight threads running in parallel in JavaFX, this sounds a little limiting.



I hope some of that is interesting for you.


Regards,
Rob.

JavaFX Week 2 - Oddities

I finished week two of the JavaPassion JavaFX course, but during the process I found some oddities that I wasn't expecting, so I've captured those details here...

Static types / Inferred types
It became obvious that with JavaFX the types can be inferred, or specified by the programmer.  As an experiment I tried to infer the type of a variable and then re-assign the value to some other value that just happened to be a different type, it turns out that's not allowed...

var x;         // Type not specified
x = "Rob";     // x becomes a String type

// But now we can't set it to an int 
// because it's not compatible!
// x = 55;     

JavaScript would enable you to re-assign anything to the variable, because it's a dynamic language and although JavaFX looks kind of dynamic, it's not.  I guess that's because it uses Java under the hood and therefore it has to be statically typed. So then I thought, how could I make this 'feel' a little more like JavaScript.  My thoughts were to simply specify that it was an 'Object', after-all everything must extend object directly, or indirectly.

var x2:Object; // So will this work?
x2 = "Rob2";
x2 = 55;       // Yes

Whether this way of thinking is wrong, I don't know yet - it's too early to tell.

JavaFX data types can't be null
Okay, this one makes me feel really un-comfortable, why wouldn't you want the ability to make something null - All of these are illegal?

// null - For the JavaFX data types, you 

// can't set them to null!
// var b:Boolean = null; // Invalid
// var i:Integer = null; // Invalid
// var n:Number  = null; // Invalid

Now, the interesting bit here is that Booleans default value is false, Integer is 0 and Number is 0.0.  Are there any exceptions to this?  Well, it appears so...

var s:String  = null; // This compiles!

Oddly the above works - but why is it different between String and Boolean for example?  This made me think - 'I know, JavaFX can re-use existing Java libraries, so if I access a Boolean from a Java class that sets it to null, it must be null!'.

JavaClass.java

package week2blog;

public class JavaClass {

    public Boolean getMeANullBoolean() {
        return null;
    }
}

Main.fx

var jc:JavaClass = new JavaClass();
var b2 = jc.getMeANullBoolean();
println("b2={b2} type:{b2.getClass()}");

// b2=null type:null

So, null is okay when integrating with existing Java code, so what can't I do it in JavaFX - I don't know yet, so I'll have to do some more digging!

My only thought was that perhaps JavaFX String is not the same as a Java String object? So one last experiment here:

println(b2.getClass());  // returns NULL!?
println(b2.TYPE);        // boolean

var myb:Boolean;
println(myb.getClass()); // returns java.lang.Boolean
println(myb.TYPE);       // boolean

Now that's odd isn't it! The JavaFX ones class is NULL, whereas the Java one is java.lang.Boolean... So this would imply that they are different?

Sequences
I like the sequence stuff - that's pretty neat, but I couldn't help but think that I don't want to do things by the index of an object in the sequence, why couldn't I look it up, for example:

var days=["Mon","Tue","Wed","Thu","Fri","Sat","Sun"];
var weekdays = days[0..4];

// Would be nice to do something like this, but I haven't
// found anything yet:
// var weekdays2 = days[0..weekdays["Fri"]];
// var weekdays2 = days[0..weekdays.indexOf("Fri")];

Expressions / functions / returning null
I have to admit I am a little confused about when a null is expected to be returned from an expression or functions.  The documentation states

the JavaFX Script programming language is an expression language, which means that everything, including loops, conditionals, and even blocks are expressions. In some cases (such as while expressions) the expressions have Void type, which means they don't return a result value.

Expressions will return the value of the last line, but functions will return null / void if no return type specified.

So taking these a bit at a time...

If this is true 'If no return value is specified, a function returns Void by default', then why does the following return a number?

function test4() {
    {
        var x = 10;
    }
}

println("test4 = {test4()}"); // this displays 10 still

If this is true 'In some cases (such as while expressions) the expressions have Void type' then I concur that this is true because this code snippet results in "Void type not allowed here".

//  In some cases (such as while expressions)

// the expressions have Void type

function test5() {
        var x = 0;
    while(x==0){
        x = 10;
    }
}

// Can't do this "'void' type not allowed here"
// println("test5 = {test5()}"); 

If this is true 'but functions will return null / void if no return type specified' then why does this return a number!...

function test() {
    return '9';
}
function test2() {
    var x=10;
}

println("test = {test()}");   // returns 9  (as a String)
println("test2 = {test2()}"); // returns 10 (as a Number)

I can only get it to nag / not return a value if I say that the function doesn't return anything, by specifying a Void return (notice the capital 'V' by the way!).

function test3() : Void {
    var x=10;
} 

// Can't do this because test3() can't return anything

// println("test3 = {test3()}");  

I hope that I have given you some food for thought, if you happen to know any answers to those oddities, then please post a reply!

Thanks all,
Rob.

JavaFX - First impressions

I have just started following a free online course from the Java Passion series (by Sang Shin). If you are also interested in joining, visit JavaPassion.com.

This post is to cover my first impressions of JavaFX (1.2), using my new MacBook (Mac OS X 10.5.8 Intel Core 2 Duo with 2Gb RAM).

My previous experience has been heavy use of Java with Swing for client-side programming and the Spring framework with JSP for server-side programming. I decided to increase my knowledge by learning how to program the iPhone and in addition learn JavaFX (which currently will not run on the iPhone - damn!).

Having no ties to Sun, these posts will be independent and may contain positive and negative views of Java FX and associated technologies.

By following the link for JavaFX.com using Firefox 3.5 on my Mac crashed FireFox the first time I visited the page. I have re-visited the page today to make this post and I am now receiving the message "An applet from 'dl.javafx.com' is requesting unrestricted access to your computer". Impact - Poor user experience. Solution - This could be FireFox 3.5 that experienced the problem, so perhaps there is nothing that Sun could do here, but an explanation or warning that I need to accept the request to download the applet should have been provided, additionally why does the applet on subsequent visits to the page require unrestricted access to my computer - this makes me nervous, surely only certain applications I launch should ask for higher permissions? Impact - Concerns over security, Solution - Explain this up-front, or make it so that JavaFX.com site does not require full permissions. Should I allow the option to 'Allow all applets from dl.javafx.com access'?! - Well I've now said yes.

After my first visit to JavaFX.com I was asked for my admin username and password within the Mac OS to install the Java FX runtime, I was surprised to find that I was not shown any progress bar or indication that the installation was happening - it looked as though it had failed.

The bottom third of the JavaFX.com website was a solid blue region with no indication that Java FX was not installed and then suddenly I noticed that this area became populated and Java FX was working. Impact - Poor user experience. Solution - A simple progress bar or 'installing' splash screen.

The headings on the website are 'Explore', 'See' and 'Learn'... Okay, is it just me that doesn't know the difference between 'explore' and 'see'? Is it obvious to you which one the samples are in? Wouldn't it be better to call it 'samples'? Explore actually gives you some marketing blurb, a break-down of what it is with a 'learn more' link, that takes you to a completely different page than the main 'Learn' button. Impact - User confusion. Solution - Yes I know this really is a pedantic thing, but simply naming the main buttons makes it a cleaner first-impression.

Within the 'see' section (sorry 'samples'), you find plenty of samples. But, in my opinion lots of them look amaturish and they are embarrasing to show as examples of how powerful JavaFX can be. Impact - Makes Java FX look crap, Solution - Move all the basic ones to a developer section as learning aids and only keep the professional looking samples. One of the samples is a video, very highly compressed, this makes video support look bad - I'm sure they done this for bandwidth reasons, but it does look poor from a user perspective.

Whilst viewing some JavaFX samples, I scrolled the browser window using the scroll-button on my mouse. During the scrolling the pages were flickering and sometimes the video seemed to disappear until I scrolled slightly further. Impact - User disappointment, solution - I guess we just have to wait until JavaFX has matured a bit, or this could be a FireFox / Mac only issue.

Whilst trying to use the JavaDoc for the first time, I was reasonably impressed with the contents of the documentation, but the user-interface seems as clunky as hell, for example, clicking on any subject causes the tree-view of the topics to jump back to the top of the screen, in fact, I'm sure it's a full page-load, shouldn't this be using AJAX by now? Also, the font's seem too big and stuff just generally takes up too much of my screen real-estate. Impact - Makes using Javadoc slow, solution - offer the typical javadoc view, it is fast, clean and good-enough, you don't have to JavaFX'ify everything you know! Oh, and a little bug in Netbeans 6.7 could be that if I select a JavaFX keyword and then right-click and choose Javadoc, it does nothing. I then try to visit the Javadoc search window and it ends up searching endlessly - never completing.

NetBeans seems to have good support for the language, the auto-completion worked a treat and the code is very easy to read - I'm very impressed with this bit. My only criticism would be that there's no built in visual editor at this stage, I certainly don't want to use Photoshop to generate a simple form and export the artifacts for integration. Although there does seem to be a program called 'DataBox' that I will be trying out soon, visit DataBox.

I've written a note on a post-it note, that says "Warnings of unrestricted access x 2, one after the other", but unfortunately I can't remember what this was all about, but I know I was thinking at the time 'This is not a good user experience'.

I did find some of the branding confusing, one minute we are on a site talking about JavaFX, then the next minute there are popups about Java Web Start and then JNLP launchers and then applets... what exactly is the user supposed to call them? Even in the samples I couldn't work out whether the ones embedded in the browser were 'applets' or 'java fx' plugins and those that popped up outside the browser were... erm, applications through web-start? Problem - confusing message, Solution - call everything Java FX and make the samples launch them all the same for consistency.

When launching the samples, some would cause a dialog to be popped up with the percentage complete, then launched in a separate browser not in-line with the page, this meant I also ended up with lots of .jnlp files in my download directory... this is messy for the user and means that I need to clean up afterwards. Solution - perhaps these .jnlp files should be in the temporary internet files location unless the user chooses to 'keep' the download?

So my overall first impressions

JavaFX language - 9 out of 10

User experience - 7 out of 10

Quality of samples - 3 out of 10

Developer support - 9 out of 10 due to lots of samples, online documentation and the JavaPassion resource.

So, if I only had one sentence to wrap up my feelings "Java FX is very satisfying from a developers perspective, but needs some polish for the users experience to improve".

Thanks for reading my first post, please post comments to keep me motivated!

Rob.