// Untested. Requires Prototype >= 1.6
//
// Copyright (c) 2009 Tobie Langel
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//  
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
 
var Observable = (function() {
  function namespace(eventName, obj) {
    return object.namespace + ':'  + eventName;
  }
  
  
  function fire(eventName, data) {
    eventName = namespace(eventName, this);
    document.fire(eventName, data);
  }
  
  function observe(eventName, callback) {
    eventName = namespace(eventName, this);
    document.observe(eventName, callback);
  }
  
  function stopObserving(eventName, callback) {
    eventName = namespace(eventName, this);  
    if (arguments.length > 1) {
      document.stopObserving(eventName, callback);
    } else {
      document.stopObserving(eventName);
    }
  }
  
  return {
    fire: fire,
    observe: observe,
    stopObserving: stopObserving
  }
})();
 
// usage (class-level namespacing):
 
var Foo = Class.create(Observable, {
  namespace: 'foo',
  doStuff: function() {
    //...
    this.fire('stuff:done', this);
    // fires a foo:stuff:done event
  }
});
 
// usage (instance-level namespacing )
 
var Foo = Class.create(Observable, (function() {
  var identifier = 1;
  return {
    initialize: function() {
      this.namespace = 'foo:' + identifier++;
    },
 
    doStuff: function() {
      //...
      this.fire('stuff:done', this);
      // fires a foo:1:stuff:done event
    }
  }
})());