Source: statemachine.js

/******************************************************************************
 * Statemachine implementation
 * ***************************************************************************/
/**
 * Describes a statemachine
 * @param obj {object} an object describing a state machine. If obj is empty then the statemachine is empty
 * @class
 */
ARCS.Statemachine = function (obj) {
    // dynamic construction: properties are initial state that have properties 
    // that are tokens and value that are the final state
    var initial = "", final = "", transitions = {}, currentState = "";

    if (obj !== undefined) {
        initial = obj.initial;
        final = obj.final;
        transitions = obj.transitions;
        currentState = "";
    }
    /**
     * Sets the initial state of the statemachine
     * @param string {string} name of the initial state
     */
    this.setInitialState = function (string) {
        initial = string;
        currentState = initial;
    };
    /**
     * Sets the final state of the statemachine
     * @param string {string} name of the final state
     */
    this.setFinalState = function (string) { final = string; };
    /**
     * Adds a transition to the state machine
     * @param start {string} name of the state at the beginning of the transition
     * @param token {string} name of the token triggering the transition
     * @param end {string} name of the state reached at the end of the transition
     */
    this.addTransition = function (start, token, end) {
        transitions[start][token] = end;
    };
    /**
     * Gives a token to the statemachine. According to its list of transitions
     * and the current state, it may trigger a transition
     * @param token {string} name of the token
     */
    this.setToken = function (token) {
        if (transitions[currentState] !== undefined) {
            if (transitions[currentState][token] !== undefined) {
                currentState = transitions[currentState][token];
                this.emit('requestSheet', currentState);
                if (currentState === final) {
                    this.emit('requestTermination');
                }
            }
        }
    };
    /**
     * Sets transitions from a list of transitions
     * @param obj {object[]} list of transitions
     */
    this.setTransitions = function (obj) { transitions = obj; };
    /**
     * Initialize and starts the statemachine, setting its current state to 
     * the initial state (by default, it is the departure of the first transition
     */
    this.start = function () {
        currentState = initial;
        this.emit('requestSheet', currentState);
    };
};


ARCS.Component.create(ARCS.Statemachine);
ARCS.Statemachine.slot("setToken");
ARCS.Statemachine.signal("requestSheet");
ARCS.Statemachine.signal("requestTermination");