StatusMachine.java

/**
 * Created by Gabriele Porcelli on 25/06/15.
 */
public class StatusMachine {

    //Replace with your statuses
    public enum MachineStatus {
        CLEAN, IS_DOING, DONE
    }

    private OnChangeStatusListener onChangeStatusListener;
    private MachineStatus machineStatus = MachineStatus.CLEAN;

    public MachineStatus getMachineStatus() {
        return machineStatus;
    }

    public void setMachineStatus(MachineStatus machineStatus) {
        if (this.machineStatus != machineStatus) {
            onChangeStatusListener.onChangeStatus(machineStatus);
            this.machineStatus = machineStatus;
        }
    }

    StatusMachine(OnChangeStatusListener onChangeStatusListener) {
        this.onChangeStatusListener = onChangeStatusListener;
    }

    public interface OnChangeStatusListener {
        void onChangeStatus(MachineStatus machineStatus);
    }
}