Introduction to Groovy
This document gets you started
with Groovy in NetBeans IDE. You will
create a Java application, add a JFrame, and retrieve a simple message from
a Groovy file.
Contents
To follow this tutorial, you need the following software and resources.
Creating the Application
In this section, we create a Java application.
- Choose File > New Project (Ctrl-Shift-N) and then select "Java Application" from
the "Java" category.
Click Next.
- In Project Name, type "GroovyJavaDemo"; in Project Location, select the folder
where the application will be created.
Make sure to unselect the Create Main Class checkbox. Click Finish.
- Right-click the application and choose Properties. In the Project Properties
dialog box, select the Groovy panel and select the Enable Groovy checkbox:
Click OK.
Creating the Java Class and the Groovy File
In this section, we create a JFrame and a Groovy class.
- Right-click the project and choose New | Other. In the New File dialog,
choose Swing GUI Forms | JFrame Form. In Class Name, type "DisplayJFrame";
in Package, type "org.demo":
Click Finish. The JFrame is created.
- Open the New File dialog again and choose Groovy | Groovy Class:
Click Next.
- In Class Name, type GreetingProvider; in Package, select the package
you created previously:
Click Finish. The Groovy file is created. Your project structure should now be as follows:
Calling Groovy from Java
In this section, we code the interaction between the Groovy file and the Java class.
- In the Groovy class, define a greeting variable within the class definition,
as shown below:
class GreetingProvider {
def greeting = "Hello from Groovy"
}
- Add a JTextField to the JFrame. In the Source view
of the JFrame, initialize the Groovy class and call its
getGreeting() method, as shown below:
GreetingProvider provider = new GreetingProvider();
public DisplayJFrame() {
initComponents();
String greeting = provider.getGreeting().toString();
jTextField1.setText(greeting);
}
Notice that you can use code completion in the Java class
to find the methods you need in the Groovy class:
- Run the application and the text from the Groovy class is shown in the JFrame:
You now know how to create a basic Java application
that interacts with Groovy.
