Beverage vending machine

© Franck.Barbier@FranckBarbier.com

Beverage vending machine is a software case study, which is implemented in PauWare. PauWare is a Java engine for executing Harel Statecharts ☛ in general.

Application Programming Interface -API-: Javadoc.

This case study aims at illustrating the use of timer events in PauWare. The simple approach is inheriting from com.pauware.pauware_engine.Core.Timer_monitor. Timer activation and inactivation may typically be assigned to a state as follows (one-shot timer event):

_Service.set_entryAction(this, "to_be_set", new Object[]{Long.valueOf(1000L)});
_Service.set_exitAction(this, "to_be_killed");

The state machine must accordingly provide an implementation for the time_out (time_out_error as well) abstract methods inherited from com.pauware.pauware_engine.Core.Timer_monitor:

public void time_out(long delay, com.pauware.pauware_engine.Core.AbstractState context) throws com.pauware.pauware_engine.Exceptions.State_exception {
    assert (delay == 1000L); // Check for what delay the timer event is received...
    assert (context.name().equals("Service"));
    _BVM_state_machine.run_to_completion("time_out");
}

• Java SE application as a Maven project Beverage_vending_machine.PauWare2Web.zip 

• This application has been designed and tested by means of PauWare ver. 2.0 (a.k.a. PauWare2, Sept. 2021). This application also reuses PauWare2Web, a PauWare2 add-on, which allows the dynamic simulation of Harel's Statecharts in a Web browser. While PauWare2 is based on Java 9, PauWare2Web requires Java 11.
• After downloading Beverage_vending_machine.PauWare2Web.zip , PauWare2 PauWare2.zip  and PauWare2Web PauWare2Web.zip  must be made accessible as Maven dependencies. PauWare2Web itself requires third-party libraries that are downloaded by Maven:
  • Java API for Processing JSON software is linked to PauWare2Web as a runtime library.
  • PlantUML Java software is linked to PauWare2Web as a runtime library.
    • Graphviz software (required by PlantUML) is a priori installed on Windows.
    • Graphviz software on macOS may be installed using Homebrew (see also here…).
  • Tyrus Java software is linked to PauWare2Web as a runtime library.
• Note that PauWare2Web can be bypassed in the code (no Web visualization then) by commenting/removing in Beverage_vending_machine.java what follows:

_BVM_state_machine = new com.pauware.pauware_engine.Core.StateMachine(… /*, new com.pauware.pauware2web.PauWare2Web_client()*/);