Control number of objects created in MooTools - class

Question

Is there a way to count the number of objects created and destroyed in mootools?
Suppose this case:
var Animal = new Class({
initialize: function(){},
create: function() {
alert('created!');
},
destroy: function() {
alert('destroyed');
}
});
var AnimalFactory = new Class({
initialize: function() {
for(i=0;i<10;i++) {
this.add(new Animal());
}
},
add: function(animal) {
this.animalsContainer.push(animal);
},
delete: function(animal) {
this.animalsContainer.remove(animal);
}
});
var animalFactory = new AnimalFactory();
I know how many animals I have created at the beginning but, imagine that somewhere in the code the animal destroy function from a concrete animal instance is called (code not shown here). how can i make the animalContainer array update correctly with one less?
Any help will be much appreciated.
Thanks!!

Answer 1

You can use the Events Class as a mix-in so that it notifies the factory of the animal's demise...
var Animal = new Class({
Implements: [Events,Options], // mixin
initialize: function(options){
this.setOptions(options);
},
create: function() {
alert('created!');
this.fireEvent("create");
},
destroy: function() {
alert('destroyed');
this.fireEvent("destroy", this); // notify the instance
}
});
var AnimalFactory = new Class({
animalsContainer: [],
initialize: function() {
var self = this;
for(i=0;i<10;i++) {
this.add(new Animal({
onDestroy: this.deleteA.bind(this)
}));
}
},
add: function(animal) {
this.animalsContainer.push(animal);
},
deleteA: function(animal) {
this.animalsContainer[this.animalsContainer.indexOf(animal)] = null;
animal = null; // gc
}
});
var foo = new AnimalFactory();
console.log(foo.animalsContainer[0]);
foo.animalsContainer[0].destroy();
console.log(foo.animalsContainer[0]);
watch it run: http://jsfiddle.net/dimitar/57SRR/
this is trying to keep the indexes/length of the array intact in case you save them