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 to the freedomotic-core.

Get familiar with Freedomotic

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

Write a message to the GUI using a Freedomotic event

In the 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, and start Freedomotic followed by the 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 the 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 a 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 read from a web service, such as a weather forecast:

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

Interact with users using a dialog box with multiple answers

You can take full advantage 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 don’t need to worry about how the external plugins works, you simply send to it a generic command. The example below uses the 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.