JavaFX and JDBC

This guide describes how to use the JavaFX technology in application development. Common questions such as how to create CRUD-oriented systems and using SQL are considered.

Task Setting

To examine the capacities of JavaFX let us consider the toursDB database from the Sun JDK v1.6 delivery and create a GUI for it.

The toursDB database contains a tourist agency's information on flights to various world destinations and the number of booked seats.

Suppose that the user registers a flight for a specific date indicating the number of economy, business and first class seats. A typical scenario of user actions would be as follows:

• look through a list of flights and find a required flight by its number or arrival/destination location

• look through the registered dates and either open the required record or register a new one

• look through information for the registered date and edit the number of seats or delete the date record altogether

We have three forms. They appear as folows:

Development Environment

In order to develop the application, you will need the free NetBeans IDE with the installed JavaFx plugin.

As a database engine this example uses Apache Derby.

To run the application JRE v1.6 should be installed on your computer. JDK is not required for running applications.

Project Creation

Create a NetBeans project using the standard procedure and specify its type as a JavaFX Application:

Add JavaFXUserLib and Derby to the project libraries:

The Derby libraries are delivered along with JDK v1.6 and are typically located in the

C:\Program Files\Java\jdk1.6.0\db\lib\ folder.

For simplicity this example uses the Derby library in embedded-mode, therefore it is enough to specify the derby.jar file in the project. For convenience, you may copy derby.jar to the project directory.

A file with a test database is located in the archive

C:\Program Files\Java\jdk1.6.0\db\demo\databases\toursdb.jar

To allow debugging within the NetBeans IDE, extract toursdb.jar to the project's root directory.

In Project Properties specify crudfx.MainFrame as the main class. This class will contain the main form of the application:

Using this configuration, you will be able to run the application directly from NetBeans.

Create a Java class called Starter and specify the following string in the main method

net.java.javafx.FXShell.main(new String[]{"crudfx/MainFrame"});

This string allows you to run the application as a Java module.

Create a new configuration for the main class:

When building the project with the second configuration, the dist folder with the application's jar file and all used libraries will be created .

Main Form of the Application

Using standard JavaFX facilities, create a form in the crudfx.MainFrame.fx file as follows:

The form contains search fields in the left-hand area and a table for results in the middle. For better visual perception, switch off the standard decoration of window borders.

Working with the Database

Remove the code that operates with the database into a separate Java-class crudfx.DataSource, bind the form's table with a model, and fill in the model by calling the static crudfx.DataSource.getFlightData(... method.

No additional resources are required in order to call Java code from JavaFX.

Operation with the database will be executed via JDBC by means of standard Java facilities.

Expanding Capacities

Some GUI components in JavaFX do not have sufficient means for adjustment. For example, in the main form the table headings and scroll bar are not adjustable.

To improve their appearance, use the crudfx.DataGrid class as a table. This class extends the Table JavaFX class. Override the createView operation:

operation DataGrid.createView():<<javax.swing.JComponent>>  {  var jComponent=super.createView();  Tools.adjustTableHeader(jComponent);  return jComponent; } 

In the static adjustTableHeader(... method of the crudfx.Tools Java class, modify the scroll bar using standard Swing facilities:

The table headings will be adjusted in almost the same way.

Code Separation

Although components initialization in JavaFX generally requires just a few lines of code, it is often convenient to place the initialization code in a separate file. For example, let all buttons from the application example differ only by their icons and called actions:

For code reuse, create the crudfx.ImageButton JavaFX class and add an operation of button creation to this class.

operation ImageButton.createButton(click:operation(),normalImage:Image,hoverImage:Image) 

Adding a button looks as follows:

...top: BorderPanel {  right: (new ImageButton).createButton   (    operation()     {      exitFromApp();     }    ,Image { url: "images/closeButton.png" }    ,Image { url: "images/closeButtonHover.png" }   )...

Date Chooser Form

When clicking on a line with a flight in the main form, open a window with flight dates:

The window will contain a list of dates and a button for registering a new date. The scroll bars of the list can be adjusted similar to those of the table in the main form.

Flight Booking Form

In the form for editing information on a booked flight, data will be entered in text fields:

Buttons will be displayed depending on whether this is a new record or an editable one:

...left: (new ImageButton).createButton (  operation()   {    if(dateModel.row==null)     {      if(DataSource.registerDate(dateModel.key,dateModel.flight_date        ,dateModel.economy,dateModel.business,dateModel.firstclass))       { me.close(); }     }    else     {      if(DataSource.updateDate(dateModel.key,dateModel.row.flight_date        ,dateModel.flight_date,dateModel.economy,dateModel.business,dateModel.firstclass))       { me.close(); }     }   }   ,Image { url: if dateModel.row == null then "images/insertButton.png"      else "images/updateButton.png" }   ,Image { url: if dateModel.row == null then "images/insertButtonHover.png"      else "images/updateButtonHover.png" } )...

Error Messages

When working with data, place the code for displaying error messages directly in the methods of the DataSource class. For example, if you are entering a date in an invalid format, a standard Swing dialog will display the message "Can't register date" along with an exception text:

This message will be sufficient for the application.

Creating Executable File

The JavaFX code has to be compiled before running, hence it is necessary to display a splash while the application is being loaded. Starting from version 6 of the Java platform you can display a splash by specifying an image in the application's manifest file using the SplashScreen-Image parameter.

Choose some animal creature as a logo:

But since forms use an image of a dandelion, it is better to use something similar in a splash. For example see the following drawing:

In the NetBeans IDE select the earlier created configuration named «test», and build the project. The CRUDFx.jar file and a folder with the used libraries will be created in the distr folder. Copy the toursDB folder with the test database to the distr folder.

To run the application, click the CRUDFx.jar.

Source Code

crudfx.zip - 5Мb

This file contains the source code, the database and the compiled application.

Conclusion

Despite JavaFX technology's beta state, the capabilities used in this technology allow you to create runnable desktop applications.

The Silverlight and Flex projects, often referred to as JavaFX competitors, can only be used for recreational or multimedia content.

Comparison of JavaFX, Flex and Silverlight Architectures

What is JavaFX?

Java FX is a set of Java libraries which compiles JavaFX Script (formerly known as F3) code into Java code (and eventually bytecode).

The script language is optimized for describing GUI layouts. Since JavaFX is build on the JRE and allows you to easily call Java classes, any tasks that cannot be solved in JavaFX directly can be handled by Java code. JavaFX is convenient and powerful.

What is Flex?

Flex is a compiler which takes an MXML description of a GUI and compiles it into a .swf file that can be displayed in a browser or run separately using the Flash plugin. The resulting .swf file is similar to Flash objects that are often presented as advertisements on web pages. There is almost no access to the file system when using Flex.

What is Silverlight?

Silverlight is a Microsoft plugin available for most major browsers on Windows and Mac (no Unix support yet). You can access Silverlight's functions from JavaScript and build a form or drawing by writing an XAML description (an XML file). In Windows you can access system components from JavaScript via OLE. Support for direct acccess to the CLR (Microsoft's runtime for C#) is under development in Silverlight v2.

Conclusion: JavaFX has an advantage by having access to the mature Java platform. All three platforms are new and under active development.