Source: mvc/StateMachine.js

  1. const collect = require('collect.js');
  2. const moment = require('moment');
  4. /**
  5.  * The class implements a classic statemachine which allow state to change
  6.  * when the {@link Transition|transtion guard function} is true.
  7.  * Upon the change the {@link Transition|transition action function} is called
  8.  */
  9. class StateMachine {
  10. 	/**
  11. 	 * The construtcor
  12. 	 * @param {Object} handler
  13. 	 * 	The object to control.
  14. 	 */
  15. 	constructor(handler) {
  16. 		if (handler == null) {
  17. 			throw Error('Illegal arguments');
  18. 		}
  19. 		this._transitions = collect({});
  20. 		this._state = 'start';
  21. 		this._handler = handler;
  22. 	}
  24. 	/**
  25. 	 * Get current state
  26. 	 * @returns {string}
  27. 	 * 	The current state
  28. 	 */
  29. 	get state() {
  30. 		return this._state;
  31. 	}
  33. 	/**
  34. 	 * Add a single transition
  35. 	 * @param {Transition} transition
  36. 	 * 	The transition
  37. 	 */
  38. 	add(transition) {
  39. 		let transitions = this._transitions.get(transition.from);
  40. 		if (transitions == null) {
  41. 			transitions = collect([]);
  42. 			this._transitions.put(transition.from, transitions)
  43. 		}
  44. 		transitions.push(transition);
  45. 	}
  47. 	/**
  48. 	 * Run the statemachine
  49. 	 * @param {Event} event
  50. 	 * 	The event.
  51. 	 */
  52. 	run(event) {
  53. 		//console.log(`${this._handler.constructor.name} ${event.toString()}`);
  55. 		let transitions = this._transitions.get(this._state);
  56. 		if (transitions == null) {
  57. 			throw Error(`No transitions found from state: ${this._state}`);
  58. 		}
  59. 		transitions.each(transtion => {
  60. 			if (transtion.canChange === undefined || transtion.canChange.call(this._handler, event)) {
  61. 				let ts = moment().format('hh:mm:ss:SSS');
  62. 				try {
  63. 					this._state = transtion.to;
  64. 					if (transtion.action != null) {
  65. 						console.log(`${ts} ${this._handler.constructor.name} State from: ${transtion.from} to: ${this._state} ${event.toString()}`);
  66. 						transtion.action.call(this._handler, event);
  67. 						return false;
  68. 					} else {
  69. 						console.warn(`${ts} ${this._handler.constructor.name} State from: ${transtion.from} to: ${this._state} ${event.toString()} has an empty action`)
  70. 					}
  71. 				} catch (e) {
  72. 					this._state = transtion.from;
  73. 					throw e;
  74. 				}
  75. 			}
  76. 		});
  77. 	}
  78. }
  79. exports.StateMachine = StateMachine;