Albertx blog

Yesterday, one of my students asked me about recovering the original data of an ArrayCollection if this ArrayCollection has a filter applied.In Adobe Flex, the ArrayCollection class has a property called filterFunction. We can assign a function reference directly to this property and then apply a refresh() to the ArrayCollection instance.This is an example.

// Defining the ArrayCollection instanceprivate var ac:ArrayCollection = new ArrayCollection([{label:"Adobe Flex", data:"Fx"},{label:"Adobe Flash", data:"Fl"},{label:"Adobe After Effects", data:"Ae"},{label:"Adobe Flash Player", data:"fp"}]);//Defining the filter functionprivate function flashFilter(obj:Object):Boolean{return obj.label.toLowerCase().indexOf("flash") != -1;}//Applying the filterac.filterFunction = flashFilter;ac.refresh();

Once the filter is applied, the ArrayCollection hides all the objects that don’t pass the validation in the function and shows the objects that do.
An ArrayCollection stores internally an instance of the Array class. You can see that in the previous example where I place an array inside the constructor of the ArrayCollection.
An ArrayCollection acts as a “wrapper” for the array instance enabling functionality that belongs to collections and lists. This functionality can be, filtering, sorting, add/remove/modify data and more.
After you filter an ArrayCollection instance the “wrapper” only shows the unhidden objects and it seems like it only has 2 elements (in my example), I mean if you test the “length” property after the filter you will see that it shows the value 2. But we know the truth, the ArrayCollection actually has 4 elements. If you want to get back this 4 elements without clearing the filter you have to deep into the ArrayCollection and find the source. This source, as I said previously, is an Array.
You will find the source using, in fact, the “source” property of the ArrayCollection. The array that will give you this property is the complete set of data that the ArrayCollection is storing without any filter. Just don’t forget that “source” is giving you an instance of an Array and not an instance of an ArrayCollection.

//continuing the previous example...//Applying the filterac.filterFunction = flashFilter;ac.refresh();//Test the length property of the ArrayCollectiontrace(ac.length); // 2//Test the source property of the ArrayCollectiontrace(ac.source) // [object Object],[object Object],[object Object],[object Object]//Test the length property of the source propertytrace(ac.source.length) // 4