Johnny Chung Lee is my nerd hero!

FlexBuilder may have its ups and downs but it still remains my pick for best AS3/MXML editor on the market (with TextMate not far behind). Part of the beauty of FlexBuilder is that it’s built on the Eclipse SDK, one of the most versatile and powerful IDEs available, which is not only free and open source, but boasts a wealth of third party plug-ins for every kind of (mostly Java) development. This article will take a look at some must-have plug-ins for doing Flex development as well as some tips for tricking out your development process.

As with all of our entries, your feedback, suggestions, corrections and additions are all more than welcome.

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There are only two ways to create a weak reference in AS3. The first is with the IEventDispatcher.dispatchEvent() method which allows you to create a weak link between the dispatcher and the listener. To quote the AS3 Bible:

ActionScript 3.0 introduces the concept of weak and strong memory references. Normally, an object will be garbage collected if there are no references to the object. That is, when no objects are using a variable, it gets thrown out. Weak references allow you to reference an object but the object will still be eligible for garbage collection unless another object holds a strong reference to the object. By setting the [eventDispatch() method’s] useWeakReference flag to true, you will create a weak link between the event broadcaster and the event listener. That way, if an event listener is deleted while still listening to the event broadcaster, the weak reference will allow it to be garbage collected. This helps to prevent memory leaks.

The other way is with the objects used as keys in a Dictionary object.

ActionScript, unlike many other languages, does not have a way to explicitly remove an object from memory. Instead it waits until all references to an object are removed and then auto-deletes it. Therefore, an object will continue to stay in memory if all strong references aren’t removed.

Below is an example of how strong-references hold an object in memory. If you’d like to try this out, copy the below text into a file called StrongReferencesExample.as

[ftf]
package {
import flash.display.Sprite;

public class StrongReferencesExample extends Sprite
{
public function StrongReferencesExample()
{
// create a new object called dog. Add it to the first leash object
// and make leash2 a copy of leash 1.
var leash1:Object = new Dog();
var leash2:Object = leash1;

// tracing both leashes will show that they hold a reference to the Dog
trace(leash1); // [object Dog]
trace(leash2); // [object Dog]

// deleting the dog from the first leash will not remove it from the second leash
// even though we originally set leash2 equal to leash1
leash1 = null;
trace(leash1); // null
trace(leash2); // [object Dog]

// The object (dog) will not be free until all of the references to it (leashes) are broken.
leash2 = null;
trace(leash1); // null
trace(leash2); // null
}
}
}
// Define a simple Dog class within the same file.
class Dog {}

[/ftf]

Richard Lord over at Big Room Games has an interesting article on hacking AS3 to allow you to create weak-references to objects. The hack is pretty decent but lacks a few things I’d like to see like strong typing at compile-time or a more refined ‘memory manager’ type functionality. However, I tried implementing both of these and came up empty handed. If you can think of a way to make this strong-typed, I’ll give you a candy bar.

Using the WeakReference hack could be useful if you want to make sure that an object will not stay in memory if you forget to delete all references to it. However, keeping track of your objects and practicing good memory management is a much better solution and hacks like this one should be saved for special cases where tracking use of an object becomes difficult or impractical.

Thanks to Alex for the link!

If you like playing with runtime arguments like memory allocation, don’t stop there. Check the list of command line arguments on the help page listed above. I use -nosplash which prevents the eclipse logo from coming up during startup. Cleaning the Eclipse application with -clean can be useful too especially after installing plugins or when things are breaking for no reason. (Mac users can skip the tedious .ini editing process and do this by typing /Applications/eclipse/eclipse -clean in the terminal.

This is slightly old news but my friend and former co-worker, Geoff Stearns, has announced the beta for version 2 of his infamous swfObject on Google code. In case you haven’t heard, swfObject is probably your best, most powerful, and easiest option when it comes to embedding Flash Player content into an HTML page. The new version was rewritten from scratch and hopefully will become the official, de-facto solution for embedding SWF files in webpages. Kudos Geoff!

So check out this egregious hack. First, you grab the stack trace by throwing and catching a dummy Error and copping its stack trace as a string. Note, that this technique only works (and is only useful) in the Debug Player.

public static function getRawStackTrace():String
{
	var stackTrace:String;
	try
	{
		throw new Error();
	} catch (error:Error) {
		stackTrace = error.getStackTrace();
	}
	return stackTrace;
}

Then you slice it up into lines, and hack those lines into their constituent parts by some crazy regular expressions. That’s pretty much it.

public static function getPartsFromStackTraceEntry(stackEntry:String):Object
{
	return stackEntry.match(/(?P<package>[\w\d\.]+)::(?P<classname>[\w\d\.\:]*?)(?P<isStatic>\$?)\/((?P<scope>[\w\d\.\:]+)::)?(?P<method>[\w\d]+\(\))(\[(?P<filename>[\w\d\\\/\.]+):(?P<line>\d+)\])?/);
}

Fun, right? The properties in the returned Object are:

• package
• classname
• isStatic
• scope
• method
• filename
• line

You can clean this up into package.classname::method with getSimplifiedStackTraceEntry().

So that’s it, it’s just some regular expressions, but with this hack you can pull out all kinds of juicy information about the context your code is running in. It can be useful for your own debugging, logging, and error reporting.

com.yourmajesty.debug.Stack View Source | Download (.as, 2k)

Okay, so you know how when you’re writing a site or app that’s of a small to medium scale, you default to storing data in XML, and you map that XML to model classes, usually pretty directly? Or, maybe you use a configuration file for your site to load in some constants or something, and XML is a pretty easy choice for this. With E4X you can really parse through that XML quickly.
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• Write headlines and use the outline view to order the big picture
• Simplify
• Base information around a task that the reader might want to do
• Write or flow without being concerned about the form then go back and edit it later
• Ask “Do I really need this?”
• Read other similar books
• Say it out loud then write down what you say
• Work on something that you know you can finish then go back to where you were stuck
• Forget about style and focus on the facts
• Take breaks and do something different like drawing a diagram or writing a code sample

Arrrgh!

Ahhhh…

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