A lock implementation using a Backbone Model and jQuery Deferred. Only one caller can "own" the lock at a time. The lock maintains an internal queue of Deferreds that it resolves, in order, as it is released.

backbone-jquery-lock.js

  var Lock = Backbone.Model.extend({
    initialize: function () {
      this._queue = [];
      this.set('_locked', false);
      this.on('change:_locked', this._on_change_lock, this);
    },

    _on_change_lock: function (m, locked) {
      if (!locked && this._queue.length) {
        var d = this._queue.shift();
        this._lock();
        d.resolve(this);
      }
    },

    _lock: function () {
      if (!this.get('_locked')) {
        this.set('_locked', true);
        console.log("Locked.");
      }
    },

    _unlock: function () {
      if (this.get('_locked')) {
        this.set('_locked', false);
        console.log("Unlocked.");
      }
    },

    acquire: function () {
      var d = new $.Deferred();
      if (this.get('_locked')) {
        this._queue.push(d);
      } else {
        d.resolve();
        this._lock();
      }
      return d.promise();
    },

    release: function () {
      this._unlock();
    }


  });