Simplify AS3 binding/event-dispatching code - apache-flex

Question

There are 3 properties (example 1):
[Bindable] public var name:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
I needed to have 3 helper methods that will be bindable too (example 2):
[Bindable] public var name:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
public function get nameIsOk():Boolean { return !Strings.isEmpty(name) }
public function get emailIsOk():Boolean { return email == 3 }
public function get addressIsOk():Boolean { return address }
Sure, the code above doesn't work. I made it work by doing this (example 3):
private var _name:String
[Bindable("nameChanged")]
public function get name():String { return _name }
public function set name(v:String):void { _name = v; dispatchEvent(new Event("nameChanged")) }
[Bindable("nameChanged")]
public function get nameIsOk():Boolean { return !Strings.isEmpty(name) }
private var _email:Number
[Bindable("emailChanged")]
public function get email():Number { return _email }
public function set email(v:Number):void { _email = v; dispatchEvent(new Event("emailChanged")) }
[Bindable("emailChanged")]
public function get emailIsOk():Boolean { return email == 3 }
private var _address:Boolean
[Bindable("addressChanged")]
public function get address():Boolean { return _address }
public function set address(v:Boolean):void { _address = v; dispatchEvent(new Event("addressChanged")) }
[Bindable("addressChanged")]
public function get addressIsOk():Boolean { return address }
It does work, but now it is bloated.
Is there a way to reduce this code (example 3) to something smaller (like example 2)?
UPDATE:
Kudos to just_a_dude for nice answer. Here is the final version:
[Bindable] public var name:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
public function Remixer() {
for each (var f:String in Strings.split("name email address")) {
ChangeWatcher.watch(this, f, onChange)
}
}
private function onChange(e:PropertyChangeEvent):void {
dispatchEvent(new Event(e.property + "Changed"))
}
[Bindable("nameChanged")]
public function get nameIsOk():Boolean { return !Strings.isEmpty(name) }
[Bindable("emailChanged")]
public function get emailIsOk():Boolean { return email == 3 }
[Bindable("addressChanged")]
public function get addressIsOk():Boolean { return address }

Answer 1

Not sure if this is what you're looking for but you can use mx.binding.utils.ChangeWatcher to "watch" for property changes
<?xml version="1.0" encoding="utf-8"?>
<mx:Script>
<![CDATA[
import mx.events.PropertyChangeEvent;
import mx.binding.utils.ChangeWatcher;
[Bindable] public var firstName:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
private var _watcher:ChangeWatcher;
private function init():void {
ChangeWatcher.watch(this, "firstName", propertyChangeHandler);
ChangeWatcher.watch(this, "email", propertyChangeHandler);
ChangeWatcher.watch(this, "address", propertyChangeHandler);
firstName = "foo";
email = 0;
address = true;
firstName = "bar";
email = 1;
address = false;
}
protected function propertyChangeHandler(event:PropertyChangeEvent):void {
var prop:Object = event.property;
var name:String = prop.toString() + "Changed";
// trace(name); // displays firstNameChanged or emailChanged or addressChanged
dispatchEvent(new Event(name));
}
]]>
</mx:Script>
Let me know if this helps
Cheers

Answer 2

I'm not sure if you need getters, but if not, a nice way to do it, is to just use a single function, and put your bindable strings as arguments.
if you put this in your object:
public function isOk(s:String):Boolean
{
return !Strings.isEmpty(s)
}
You would use it like this:
<mx:CheckBox selected="{yourObject.isOk(yourObject.name)}" />
Generally, if you put a function inside the "{}" with parameters which are bindable, it will be called each time that parameter changes.

Answer 3

I would encapsulate your functionality in a class. Do not repeat yourself :)