Control number of objects created in MooTools

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