ExternalTransition calls the same method twice

[dsGCloud]

This is my first FSM in Java, and Squirrel has been an amazing tool for that. But I'm having a problem.

public class OrangutanWriter {

public static void main(String[] args) {
    StateMachineBuilder<OrangutanWriterFSM, FSMState, FSMEvent, Void> builder = StateMachineBuilderFactory
            .create(OrangutanWriterFSM.class, FSMState.class,
                    FSMEvent.class, Void.class);

    builder.onExit(FSMState.StandBy).callMethod("exitStandBy");

    builder.externalTransition().from(FSMState.StandBy).to(FSMState.Stream)
            .on(FSMEvent.Connected).callMethod("entryStream");

These are some of the transitions defined, but when "FSMEvent.Connected" happens, the FSM enters two times to the method "entryStream".

I have this sysout at the beginning of the method.

System.out .println("\n--------------------------------------Entering to Streamming--------------------------------------" + "\nFrom:" + from + " - To: " + to + " - Event triggered: " + event);

and I get this at the console.

--------------------------------------Entering to Streamming-------------------------------------- From:StandBy - To: Stream - Event triggered: Connected Stream Service has Started @ 3600

--------------------------------------Entering to Streamming-------------------------------------- From:null - To: Stream - Event triggered: Connected Stream Service has Started @ 3600

Is this normal, am I defining something wrong?

Thanks for the assistance.

Spartan

[hekailiang]

Thanks for reporting this issue. Normally transition should only be triggered once when single event fired. I don't know what is the problem now. It would be helpful if you could provide complete runnable test case to reproduce the issue.

[dsGCloud]

It's weird because I'm just checking the FSM with keyboard events.

public class OrangutanWriter {

private static OrangutanWriterFSM StateMachine;

public static void setup() {
    StateMachineBuilder<OrangutanWriterFSM, FSMState, FSMEvent, Void> builder = StateMachineBuilderFactory
            .create(OrangutanWriterFSM.class, FSMState.class,
                    FSMEvent.class, Void.class);

    builder.onExit(FSMState.StandBy).callMethod("exitStandBy");

    builder.externalTransition().from(FSMState.StandBy).to(FSMState.Stream)
            .on(FSMEvent.Connected).callMethod("entryStream");

    builder.onExit(FSMState.Stream).callMethod("exitStream");

    builder.externalTransition().from(FSMState.Stream).to(FSMState.Encode)
            .on(FSMEvent.EncodeList).callMethod("Encode");

    // 4. Use State Machine
    StateMachine = builder.newStateMachine(FSMState.StandBy);

}

public static void main(String[] args) {
    setup();
    StateMachine.start();

    while (true) {
        int myint = 0;
        Scanner keyboard = new Scanner(System.in);
        System.out.println("You are at: " + StateMachine.getCurrentState()
                + "\nEnter an integer:");
        myint = keyboard.nextInt();
        switch (myint) {
        case 1:
            System.out.println("My Int = " + myint);
            StateMachine.fire(FSMEvent.Connected);
            myint = 0;
            break;

        case 4:
            StateMachine.fire(FSMEvent.EncodeList);
            break;

        case 5:
            StateMachine.fire(FSMEvent.StopEncode);
            break;
        default:
            break;
        }
    }

}

}

[rookie0peng]

FSM will call method "exitStandBy" when you initial FSM. like this. StateMachine = builder.newStateMachine(FSMState.StandBy); Because of this code. builder.onExit(FSMState.StandBy).callMethod("exitStandBy"); You can avoid initial call by check FSMEvent is not null. protected void exitStandBy(FSMState from, FSMState to, FSMEvent event, Void context) { if (event != null) { //your code } }