MATE: Using the PropertySetter tag

I’ve never understood why many MATE developers don’t use proper getter/setter properties within Managers. I’ve just assumed it is because MethodInvoker is the preferred means to communicate with Managers. Setting an individual property on a Manager hasn’t been an easy thing to do, until now, so I wonder if that will change?

Having read through similar discussions on the forums however, I’m not convinced MATE purists will like/agree with this post, but I feel most confortable with property getter/setter properties and it has always been a common method in ActionScript.

Mate 0.8.6 included a new tag called PropertySetter and my eyes lit-up as soon as I read it on the change log. The PropertySetter tag (there’s no documentation for this tag yet) allows you to communicate with Managers by directly assigning values to a property, and using getter/setter property functions to check, manipulate and fire off other events as necessary.

Before the PropertySetter tag my EventMap used to communicate with Managers like this:

<EventHandlers type="{PreferencesEvent.BREAK_LENGTH}" debug="false">
<MethodInvoker generator="{ApplicationManager}" method="setBreakLength" arguments="{event.value}" /></pre>
</EventHandlers> 

and the related methods within my Managers used to look like this:

private var _breakLength : int = 0;

[Bindable(event="breakLengthChanged")]
public function get breakLength () : int
{
	return _breakLength;
}

public function setBreakLength (value : int) : void
{
	breakLength = value;
}

notice the use of a proper property getter function, but no proper property setter function – that has always felt so awkward to me. With the PropertySetter tag, I can now set a property in my Manager from my EventMap like this:

<EventHandlers type="{PreferencesEvent.BREAK_LENGTH}" debug="false">
<PropertySetter generator="{ApplicationManager}" targetKey="breakLength" source="{event.value}" /></pre>
</EventHandlers> 

and use proper property getter/setter functions in my Manger like this:

private var _breakLength : int = 0;

[Bindable(event="breakLengthChanged")]
public function get breakLength () : int
{
	return _breakLength;
}

public function set breakLength (value : int) : void
{
	_breakLength = value;
	dispatchEvent(new Event('breakLengthChanged'));
}

I’m not sure what the general community at large thinks? I’ve started a thread over on the mate forums to discuss it, but it would be great to hear other peoples opinions on what should be best practice.

Filed under: ActionScript, flex, frameworks, mate