Java FX Script

The JavaFX Script programming language (known as JavaFX) is a declarative, statically typed scripting language from Sun Microsystems, Inc. As mentioned on the Open JavaFX (OpenJFX) web site, JavaFX technology has a wealth of features, including the ability to make direct calls to Java technology APIs. Because JavaFX Script is statically typed, it also has the same code structuring, reuse, and encapsulation features; such as packages, classes, inheritance, and separate compilation and deployment units, which make it possible for you to create and maintain very large programs using Java technology.

This article will help you get started with the JavaFX programming language is an introduction to the JavaFX programming language, targeted to those who are already familiar with Java technology and the basics of scripting languages.

The JavaFX Pad Application
If you have a Java Runtime Environment (JRE) on your system, the easiest way to get started with JavaFX technology is to fire up the Java Web Start-enabled demonstration program, JavaFX Pad. Once you start the application, you should see a screen similar to what appears in Figure 1

Figure 1. The JavaFX Pad Application Running on Microsoft Windows OS, JDK 6

JavaFX Pad starts with a default application already loaded, which it immediately executes. The JavaFX Pad application is a great way to see exactly what you're doing at runtime, modifying changes as you go, and instantaneously seeing the results

JavaFX Technology: A Statically Typed Language

The JavaFX programming language is a scripting language with static typing. What exactly does this mean? Consider the following:

var myVariable = "Hello";

This declaration, similar to what you may find in JavaScript technology, creates a variable called myVariable and assigns it the string value Hello. However, after declaring the variable, let's try to assign it something other than a string:

myVariable = 12345;

Because the code does not use quotation marks around 12345, this variable is now being assigned an integer instead of a string. In JavaScript technology, dynamically retyping the variable will work fine. However, a statically typed language such as JavaFX will not allow this. This is because myVariable was initially declared as a String type, and the code later tries to reassign it as an integer. With JavaFX, a variable that is declared as a String must remain a String.

In fact, if you enter those two lines of code into the JavaFX Pad demo, you'll immediately see an error at the bottom of the window, as shown in Figure 2.

Using EJB with AJAX

AJAX

AJAX is an acronym for Asynchronous JavaScript And XML. AJAX is not a new programming language, but simply a new technique for creating better, faster, and more interactive web applications. AJAX uses JavaScript to send and receive data between a web browser and a web server.

It makes web pages more responsive by exchanging data with the web server behind the scenes, instead of reloading an entire web page each time a user makes a change. AJAX is a technology that runs in your browser. It uses asynchronous data transfer (HTTP requests) between the browser and the web server, allowing web pages to request small bits of information from the server instead of whole pages. It makes Internet applications smaller, faster and more users friendly.

What is it?
A traditional web application will submit input (using an HTML form) to a web server. After the web server has processed the data, it will return a completely new web page to the user.
Because the server returns a new web page each time the user submits input, traditional web applications often run slowly and tend to be fewer users friendly.

With AJAX, web applications can send and retrieve data without reloading the whole web page. This is done by sending HTTP requests to the server (behind the scenes), and by modifying only parts of the web page using JavaScript when the server returns data.
XML is commonly used as the format for receiving server data, although any format, including plain text, can be used.

The standard and well-known method for user interaction with web-based applications involves the user entering information (e.g. filling out a form), submitting that information to the server, and awaiting a page refresh or redirect to return the response from the server.
This is at times frustrating for the user, besides being rather different to the 'desktop' style of user interface with which (s)he may be more familiar.
Ajax (Asynchronous Javascript And XML) is a technique (or, more correctly, a combination of techniques) for submitting server requests 'in the background' and returning information from the server to the user without the necessity of waiting for a page load.
Ajax is actually a combination of several technologies working together to provide this capability.

How does it work?
Instead of a user request being made of the server via, for example, a normal HTTP POST or GET request, such as would be made by submitting a form or clicking a hyperlink, an Ajax script makes a request of a server by using the Javascript XMLHTTPRequest object.
Although this object may be unfamiliar to many, in fact it behaves like a fairly ordinary javascript object. As you may well know, when using a javascript image object we may dynamically change the URL of the image source without using a page refresh. XMLHTTPRequest retrieves information from the server in a similarly invisible manner.
AJAX in EJB:

Enterprise applications can use Ajax to provide better Web interfaces that increase the user productivity. In many cases, it is possible to submit a partially completed form to obtain useful information from the server application. For example, the server could perform some early validation or it could use the partial user input to suggest values for the empty form fields, speeding up the data entry process. Ajax can also be used to connect to data feeds whose information is displayed without refreshing the whole page.

The following diagram depicts the EJB-AJAX application's architecture: