Let us create the first application project with the tools installed in the previous section. First launch Eclipse and follow the following steps:

Figure 1.10. A New Dynamic Web Service Project

Feel free to explore the contents of the newborn project. Your source code will usually go under the src folder. IT Mill Toolkit libraries and any resource files will be placed under the WebContent folder, which contains all material that is to be published to the web server.

You need to include the IT Mill Toolkit library package in the project. Copy the following JAR package from the directory where you unpacked IT Mill Toolkit distribution to WebContent/WEB-INF/lib folder:

Perhaps the easiest way to include the library is to import it.

Notice that Eclipse does not show the imported library under WebContent/WEB-INF folder where you imported it, but under Java Resources → Libraries → Web App Libraries.

You can observe that the library has appeared in the project classpath by selecting Project → Properties and in the Properties window selecting Java Build Path → Libraries → Web App Libraries.

We will next look into how to create the application class.

The skeleton of the file will be opened in the editor and will look as follows.

import com.itmill.toolkit.Application;

public class MyApplication extends Application {

	@Override
	public void init() {
		// TODO Auto-generated method stub
	}
}

You can now write the source code. The Hello World application above provides a simple example for creating a minimal application.

We will use the Calculator demo application in the rest of this section as an example. You can import the source file into the project by right-clicking the project folder and selecting Import → Import.... From the Import dialog, select General → File System, click Next. Click Browse to select the demo directory from the installation package, browse to WebContent/src/itmill/toolkit/demo, and click Ok. Check the Calc.java in the list on the right. In the Into folder field, enter myproject/src/com/itmill/toolkit/demo to import the source file under the com.itmill.toolkit.demo package. Finally, click Finish.

You need to set up the application environment as described in the section called “Application Environment” and provide a deployment descriptor WebContent/WEB-INF/web.xml for the application.

The new web project in Eclipse contains a template for the deployment descriptor. By default, Eclipse opens the file with XML editor. To use text editor, right-click on the web.xml file and select Open With → Text Editor. The template contains a <welcome-file-list> block, which you can remove if you like.

The contents of the descriptor for the Calc application are given in the example below.

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
                        http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <servlet>
        <servlet-name>myservlet</servlet-name>
        <servlet-class>com.itmill.toolkit.terminal.gwt.server.ApplicationServlet
        </servlet-class>
        <init-param>
            <param-name>application</param-name>
            <param-value>com.itmill.toolkit.demo.Calc</param-value>
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>myservlet</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
</web-app>

The descriptor defines a servlet with name myservlet. The servlet class, com.itmill.toolkit.terminal.gwt.server.ApplicationServlet, is provided by IT Mill Toolkit framework and it should be the same for all IT Mill Toolkit projects. The servlet takes the class name Calc of the user application class as a parameter, including the full package path to the class. If the class is in the default package the package path is obviously not used.

For a more detailed treatment of the web.xml file, see the section called “Deployment Descriptor web.xml”.

Now everything should be in place and your Eclipse should look like this:

Figure 1.11. A Ready Project

In a production-ready project, you should also have widget sets and themes in the WebContent/ITMILL directory. The default widget sets and themes are included in the JAR library, but accessing them from a JAR is inefficient. We recommend installing the ITMILL directory so that it can be accessed directly from the web server. You can copy the directory from under the IT Mill Toolkit installation directory to the WebContent directory in your project, or extract it from the JAR package.

Eclipse IDE for Java EE Developers has the Web Standard Tools package installed, which supports control of various web servers and automatic deployment of web content to the server when changes are made to a project.

Make sure that Tomcat was installed with user permissions. Configuration of the web server in Eclipse will fail if the user does not have write permissions to the configuration and deployment directories under the Tomcat installation directory.

Follow the following steps.

If you have everything set up as described above, all the rest is easy. Just head your web browser to http://localhost:8080/myproject/.

Figure 1.12. Running an IT Mill Toolkit Application

To examine how the application works, you can insert break points in the Java code by double clicking on left marginal bar of the source code window. A small magnifying glass will indicate the breakpoint. If you insert a breakpoint in the buttonClick() event handling method and click any button in the calculator, eclipse will ask to switch to the Debug perspective. Answer Yes and the Debug perspective will open where the execution stopped at the breakpoint. You can examine the state of the application and even make some changes and then select Resume from Run menu to continue the execution.

Figure 1.13. Debugging an IT Mill Toolkit Application

The procedure described above allows debugging the server-side application. If you develop client-side widgets with Google Web Toolkit (GWT), the GWT Hosted Mode Browser allows you to debug the widgets. For more information on debugging client-side widgets, see the section called “Hosted Mode Browser”.