The ‘Hello World’ Plugin

Here you’ll learn how to add features starting from the hello-world plugin. This plugin is made of some boilerplate java code that you can use as base to create your own plugin.

Open the freedomotic maven project with your favourite IDE and compile it if not already done. This will build a set of modules; remember the freedomotic-core module is the Freedomotic runtime, start it from your IDE to have it running.

Now open the hello-world module in your IDE and compile it. It will be automatically installed into the freedomotic-core.

Get familiar with Freedomotic

Here are some simple changes you can do with the plugin “hello-world”.

Write a message to the GUI using a Freedomotic event

in onRun() method of your plugin write:

protected void onRun() {
  //get and format the current date and time
  DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
  Date date = new Date();
  //create a freedomotic message event
  MessageEvent message = new MessageEvent(null, "Hello world plugins says current time is " + dateFormat.format(date));

then build your plugin, start Freedomotic and then your plugin. You will see a blue bubble with the current date and time at the upper left side of the environment map.

Make your plugin send emails

in onRun() method of your plugin write:

protected void onRun() {
    MessageEvent message # new MessageEvent(this, "The mail text");
    message.setType("mail"); //send this message as an email
    message.setTo(""); //the destination mail address


this requires the Mailer plugin to be installed and properly configured.

Change a thing location on the map

This piece of code iterates over all loaded things and moves objects of type Person to a random location. The randomLocation() function should be implemented and must return an com.freedomotic.model.geometry.FreedomPoint type (remember to add freedomotic-model.jar to your classpath)

protected void onRun() {
    for (EnvObjectLogic anObject : EnvObjectPersistence.getObjectList()) {
        if (anObject instanceof it.freedomotic.objects.impl.Person){
            Person person = (Person)anObject;
            FreedomPoint location = randomLocation();

Change things state programmatically

If you want to change the object state according to a value readed from a web service like a weather forecast service:

If you want to change the object state according to a value readed from an hardware device like an Arduino relay board:

Interact with users using a dialog box with multiple answers

You can take full advantages of other installed modules from your plugin. For example you can use a third party text to speech plugin to make it say something programmatically from your plugin.

You haven’t to worry about how the external plugins works, you simply send to it a generic command. The example below uses Jfrontend plugin to prompt a dialog with three choices.

public void askSomething() {
 final Command c = new Command();
 c.setName("Ask something silly to user");
 c.setProperty("question", "<html><h1>Do you like Freedomotic?</h1></html>");
 c.setProperty("options", "Yes, it's good; No, it sucks; I don't know");
 c.setReplyTimeout(10000); //10 seconds

 new Thread(new Runnable() {
   public void run() {
     Command reply = Freedomotic.sendCommand(c);
       if (reply != null) {
           String userInput = reply.getProperty("result");
             if (userInput != null) {
               System.out.println("The reply to the test question is " + userInput);
                } else {
                    System.out.println("The user has not responded to the question within the given time");
                } else {
                   System.out.println("Unreceived reply within given time (10 seconds)");

Add a GUI to the plugin

To add a graphical interface you must create a Jframe and link it to the plugin in onStart() with the following code

gui = new PluginJFrame();

To open the GUI right click on the plugin icon.